COMPARATIVE ANATOMY. 



meleon, newt, salamander, igu- 

 ana, &c. 



II. Serpentla. No external members ; 

 body ot" an elongated form, and viscera of 

 a similar shape ; they are oviparous ; but 

 the egg is sometimes hatched in the ovi- 

 duct ; both jaws moveable. 



1. OotaUis, rattlesnake. 



2. Boa. Immense serpents of India 



and Africa. 



3. Coluber, viper. 



4. Anguis, blind worm. 



5. Amphisbsena. 



6. Csecilia. 



Fishes. Breathe by means of branchiae 

 r gills, and have no trachea, nor larynx ; 

 organs of motion consisting of fins; nose 

 unconnected with the organs of respira- 

 tion ; ear entirely enclosed in the head, 

 the tympanum, &c. being absent; both 

 jaws moveable ; the place of the pancreas 

 supplied by the pyloric ceeca ; an urinary 

 bladder ; two ovaries ; heart consisting of 

 a single auricle and ventricle. They may 

 be distributed into two leading divisions : 

 the cartilaginous, whose skeleton consists 

 of cartilage ; the bony, where it is formed 

 of a more firm substance. 



(A) CARTILAGINOUS FISHES. 



Order "I. Ghondropterygii , having no 

 gill-cover ; an uterus, with two oviducts. 



1. Petromyzon, lamprey. 



2. Gastrobrarichus. 



3. Raia, skate, torpedo, stingray. 



4. Squalus, shark, saw-fish. 



5. Lophius, sea-devil, frog-fish. 



6. Balistes, file-fish. 



7. Chimaera. 



H. Brancldoslegii ,- having a gill-cover. 



1. Accipenser, sturgeon, beluga. 



2. Ostracion, trunk-fish. 



3. Tetrodon. 



4. Diodon, porcupine-fish. 



5. Cyclopterus, lumpsucker. 



6. Centriscus. 



7. Syngnathus, pipe-fish. 



8. Pegasus. 



(B) HONY FISHES, DIVIDED ACCORDING TO 

 THE SITUATION OF T1IKIU FISTS. 



Order I. Apodes ; no ventral fins. 



1. Murxna, eel-kind. 



2. Gymnotus, electrical eel. 



3. Anarrhichas, sea- wolf. 



4. Xiphias, sword-fish. 



5. Ammodites, launce. 



6. Ophidium. 



7. S'romateus. 



8. Trichiurus. 



II. Thoracici ; ventral fins directly un- 

 der the thoracic. 



1. Echeneis, sucking-fish. 



2. Coryphaena, dorado. 



3. Zeus, dory. 



4. Pleuronectes, flounder, plaice, dab, 



holibut, sole, turbot. 



5. Chaetodon. 



6. Sparus. 



7. Perca, perch. 



8 Scomber, mackarel, bonito, tunny. 

 9. Mullus, mullet, &c. &c. 



III. Jib dominates ; ventral fins behind 

 the thoracic ; chiefly inhabit fresh water. 



1. Cobitis, loach. 



2. Silurus. 



3. Salmo, salmon, trout, smelt. 



4. Esox, pike. 



5. Clupea, herring, sprat, shad'. 



6. Cyprinus, carp, tench, gold-fish, 



minow, &c. &c. 



4 



IV. Jugulures , ventral fins in front of 

 the thoracic. 



1. Gadus, haddock, cod, whiting, 



ling. 



2. Uranoscopus, star-gazer. 



3. Blennius, blenny. 



4. Callionymus, dragonet. 



5. Trachinus, weaver. 



The animals, which have no vertebral 

 column, do not possess so many common 

 characters as the vertebral classes ; their 

 hard parts, when they have any, are ge- 

 nerally placed on the surface of the body ; 

 the centre of the nervous system, instead 

 of being mclosed in a bony case, lies in 

 the same cavity with the viscera ; the oeso- 

 phagus is generally surrounded by a ner- 

 vous chord coming from the brain ; their 

 respiration is not carried on by lungs, and 

 they have no voice ; their jaws move in . 

 various directions ; they have no urinary- 

 secretion. 



The invertebral animals were distribut- 

 ed by Linnaeus into two classes; insects 

 and worms (vcrmes.) The anatomical 

 structure of these animals was very irn-" 



