Stellio phyllurus.

Family 5.-CAMELEONES. See CAMELEO.
Family 6. SCINCIOIDES.

Feet short; tongue not extensible; scales imbricated.

Gen. 1. Scinci of Daud.-Body smooth and tapering.

Lacerta scincus of Linné.

Gen. 2. Sepses of Daud.-Body still more elongated; feet smaller; hairs wide apart. Anguis, quadrupes of Linné.

Gen. 3. Bipedes of Lacep.-Fore feet wanting. Lacerta apus of Gmelin."

Gen. 4. Chalcides of Daud.-Body very much elongated; feet short and distant, very like the serpentes, but the scales are ranged in transverse bands. Lacerta chalcis, chamossura; cophias of Sch. L. anguina.

Gen. 5. Chirotetes of Cuvier. Hind feet wanting. Lacerta lumbricoides of Shaw.

ORDER III.-SERPENTES.

Family 3. SERPENTES VENENOSI.

The first tooth in the upper jaw larger than the rest, and tubular for conducting the poison.

Gen. 1. Bonguru of Daud.-Back carinated. Gen. 2. Trimesurus of Lac.-Back without any peculiarity.

Gen. 3. Hydrus.-Body very much compressed. Gen. 4. Hydrophis.-A row of scales somewhat larger than the rest under the belly.

Gen. 5. Pelamides.-Occiput inflated to make room for the lengthened pedicles of the lower jaw. Anguis platurus.

Gen. 6. Chersydrus of Cuvier.-The head and the whole body equally covered with scales. Acrochordius fasciatius of Shaw.

Family 4.-SERPENTES VENENOSISSIMI. Their superior maxillary bones are very small;

means of alternate doublings of the body.

ternal pterygoid or apophysis of the spheroid, and are very moveable: there is fixed in them a sharp tooth hollowed by a canal that affords an exit to a humor secreted by a gland seated under the eye. This tooth is concealed in a fold of the gum when at rest; behind it there are many germs destined in their turn to replace it, should it be lost in the exercise. This fang was once looked upon as moveable, but it is the jaw bone that is moved; there are no other teeth in the upper jaw bone besides this, but two ranks in the palate. Group 1. Crotali.

Gen. 1. Crotalus.

Gen. 2. Scatate of Latham.-Entire plates under the body, and under the tail.

Gen. 3. Acanthophis of Daud.-Double plates at the end of the tail, which is terminated by a spine. Gen. 4. Lamgaia of Brug.-Plates behind the anus, surrounding the tail.

Langaia, rasuta of Shaw.

Group 2. Vipera.

Integuments like those of the Coluber.

Gen. 1. Trigonocephalus.—Fossal behind the nostrils; tail generally ending in a small point; occiput enlarged.

Gen. 2. Platurus.-Tail compressed; head covered with plates.

Gen. 3. Naia.-In progression the part of the body next the heart enlarged into a disk. C. maia of Linné.

Gen. 4. Elaps of Schneid.-Head, owing to the shortness of the os tympanique and the mastoid bones, even with the rest of the body. Coluber lemniscatus of Linné.

Gen. 5. Vipera.-Head covered with granulated scales.

Coluber berus of Linné.

C. vipera cerastes.

Gen. 6. Cobra.-Head imbricated, with carinated scales.

Family 5. SERPENTES NUDI.

Gen. CECILIA, which see.-The articulation of the vertebra is formed by two facettes of a hollow cone filled with gelatinous cartilage as among fishes, and their cranium is united to the first vertebra by a pair of tubercles, as in the batrachi; the maxillary bones cover the orbit, which is like a simple orifice; and the temporal bones cover the temporal foss in such a manner that the head presents nothing but shell of bony continuity. The auricle is not sufficiently divided in this genus to be regarded as double; their second lung is very small; it appears that they place their eggs in a semi-membranous tube, and unite them into long

chains.

pass onwards to discuss the nature of this part of our arrangement.

Pisces ossibus ex cartalagine concretis. Skeleton cartilaginous, the calcareous matter being deposited in small grains and not in fibres nor filaments; the cranium, owing to the plastic nature of the material, destitute of sutures, but described into portions by means of certain prominent lines.

ORDER I.

Branchiæ fixed to the skin by their outward edge, to which the water has access through a certain number of apertures in the sides of the neck. Division I.-CYCLOSTOMA.

Skeleton the most imperfect of all the fishes; no pectoral nor ventral fins; body elongated, and terminating before in a circular or semicircular lip of a fleshy consistence, which is supported by a cartilaginous rising, resulting from the commutual union of the mandibles and the palatine bones. Petromyzon of Linné. Branchial apertures seven.

Gen. 1. Petromyzon of Dum.-Maxillary ring armed with strong teeth.

P. maximus.

P. fluvialis.

P. planeri of Bl.

Gen. 2. Ammocates of Dumer.-Skeleton soft and membranous; no teeth.

P. branchialis of Linné.

Division II.-PLAGIOstoma.

Their palatine bones and their postmandibles only are armed with teeth and fulfil the office of

Animals with a double circulation, but the respiration is performed through the mediation of water, which is effected by means of an apparatus called the branchia, consisting of leafy folds suspended by bony arches, which are connected with the os hyoides, and are severally composed of a great number of lamine, which may be separated like the threads of the warp when the woof is unravelled; the tissue which invests these laminæ is replenished with countless branchings of bloodvessels. We shall presume that the reader is already acquainted with the distinctions to which the fins are from their relative position subject, and

exists no vestige; a single bone suspends the apparent jaw bones to the cranium, and at once represents the os tympanique, the zygomatic arch, and the temporal bone.

characters of the mustelus a spine before each dorsal fin.

Squalus philippi.

Gen. 10. Spinar of Cuvier. Unite most of the characters belonging to the preceding genera, but chiefly distinguished by the absence of an anal fin. Gen. 11. Centrina of Cuvier. Squalus centrina of Linné. Gen. 12. Scymnus of Cuvier. Squalus Americanus.

Family 2. SQUATINE of Dum.

Gen. 1. Squatina.-Opening of the mouth at the anterior edge, and not underneath as in the preceding family; eyes seated upon the upper surface.

Squalus squatina of Linné.

Gen. 2. Pristis. Snout prolonged into a depressed beak, armed on each side with strong bony spines. Squalus pristis of Linné.

Family 3. RALE.

Gen. 1. Rhinobatus.-Tail thick and fleshy.
Raia rhinobatus.

Gen. 2. Rhina.-Snout short, broad, and round.
R. ancylostomus.

Gen. 3. Torpedo.-The seventh pair of nerves curiously ramified and spread over a large portion of the body.

Gen. 4. Raia. They present a disk of a rhomboidal form.

R. clavata of Linné.

R. ruba of Linné.

R. batis of Linné.

Gen. 5. Trygon of Adams,-Tail armed with a serrated sting.

Raia pastinaca of Linné.

Gen. 6. Myliobates of Dum.-Head prominent.
Raia aquila of Linné.

Gen. 7. Cephaloptera.-Differs from the trygon chiefly in having the teeth thin and finely denticulated.

Family 4. CHIMERE of Linné.

Gen. 1. Chimera of Cuv.-Snout simply conical.
C. monstrosa of Linné.

Gen. 2. Callorynchus of Grov.-Snout terminated by a fleshy lip.

C. callorynchus of Linné.

ORDER II.-CHONDROPTERYGII. Branchiis liberis. Gills furnished with an operculum, but the branchiostegous membrane is without rays.

Gen. 1. Acipenser of Linné.

Gen. 2. Spatularia of Shaw.-Recognised by an. enormous extension of the mouth, which by its widened edges puts on the figure of a leaf.

Squalus spatula of Manduil. Found in the Mississippi.

ORDER III. PLECTOGNATHA.

Skeleton of a fibrous texture; maxillary bone firmly attached to the intermallary side, which alone forms the jaw; the palatine arch is jointed by a suture to the cranium; opercula and the gills concealed under the skin, and visible only through a small cleft.

Family 1. GYMNODONTES.

An ivory substance in the room of teeth, which consists internally of plates. The apparent bill thus formed must be considered as resulting from the confluence of the mere teeth; for it is further observable that there is a certain disposition in the bones of the head to blend with each other, owing

no doubt to the soft and plastic nature of their materials.

Gen. 1. Diodon of Linné.

Gen. 2. Tetraodon of Linné.

Gen. 3. Cephalotus orthagorinus of Sch.-This genus differs from the diodon in having the body compressed and without spines.

Family 2. SCLERodermata.

Snout conical or pyramidal, prolonged from the eyes, terminating in a small mouth, which is armed with a few distinct teeth; skin covered with hard scales.

Gen. 1. Balistes.-Scales large, very hard, and of a rhomboidal form. See BALISTES. B. capriscus.

Gen. 2. Monocanthus of Cuvier. Balistes Chinensis. Scales very small, roughened by stiff and compact scabrosities.

Gen. 3. Aluterus of Cuvier.

Balistes monoceros of Linné.-Body elongated, covered with small compact grains.

Gen. 4. Triacanthus of Cuvier.-Each ventral supported by a large thorny ray.

Gen. 5. Ostracion. See OSTRACION.

ORDER IV.-LOPHOBRANCHIA.

Branchiæ divided into small round crests, disposed in hairs along the branchial arches, and enclosed under a large operculum, which is so attached by a membrane as to leave only a small chink for the exit of the water.

Destitute of adipose substance; upper jaw formed, as in the trouts, in the middle by intermaxillary bones without pedicles, and at the sides

by the maxillary.

Gen. 1. Clupea.

C. harengus.
Gen. 2. Meglops.

Clupea cypoernoides of Bl.
Gen. 3. Engraulis of Cuvier.
Clupea encrasicholus of Linné.
Gen. 4. Thrissa of Cuvier.
Clupea atherinoides of Bl.
Pristigaster of Cuvier.
Notopterus of Laap.
Gymnotus notopterus of Pall.
ELOPS of Linné.

CHIROCENTRUS of Cuvier. Tongue and branchial arches rough with carded teeth; structure of the jaws resemble the clupeæ.

ERYTHRINUS of Gronov. Esox Malabaricus of Bl.
AMIA of Linné.

Sudis.-Dorsal and anal fins nearly opposite and nearly equal.

Lepisosteus.-Scales of a stony hardness.

Esox osseus.

Esox lucius of Linné.

No cœcal appendages; natatory bladder very small.

Gen. 1. Anableps.-Eyes prominent, beneath a vault formed on each by a production of the frontal bone; cornea and iris divided into two portions by transverse bands.

Cobitis anableps of Linné.

Cen. 2. Pacilia, Schn.-Jaws flattened horizontally; furnished with very fine teeth.

Poecilia vivipara, Schn. Small fish inhabiting the fresh waters of America.

Gen. 3. Lebias of Cuvier.-Differs from the last

in having the teeth denticulated.

Gen. 4. Cyprinodous, Lacep.-Teeth carded; in other respects very like the pœciliæ.

SILUROIDES. Destitute of true scales; intermaxillary bones suspended under the ethmoid, from the edge of the jaw; maxillary bones reduced to simple vestiges. Intestine ample and folded;

Gen. 5. Chauliodus, Schn.

Esox stomias of Shaw.

permit us to notice particularly, and there is less need of description in this place, because their general notes of distinction are obvious and natural.

Gen. 1. Malapterurus, Lacep.-Destitute of true fins upon the back, and only a small adipose one upon the tail.

Silurus electricus of Linné.

Gen. 2. Aspredo of Linné.-Head flattened; body widened by the extension of the shoulder bones.

Silurus aspredo of Linné; platystacus lævis. Bl.

Group 3. Loricaria.

No cœcal appendages, nor natatory bladder; true opercula immoveable.

Gen. 1. Hypostomas, Lacep.-Labial veil simply papillose.

Gen. 2. Loricaria.—Labial veil furnished with cirrhi at the edges.