552 BIOLOGY. 



muscles, and a lingual bone, as in Man ; Fishes are, as 

 regards the development of this sense the Glossozoa, 

 Lingual or Tongue-animals. 



3350. As Fishes are the repetition of the intestine and 

 vitellus, so they may be termed abdominal or rather 

 Pelvic animals. They are an abdomen, unto which are 

 appended branchiae, fins and head. 



They are the repetition of the Infusoria, Mussels, and 

 Worms ; in them we meet with mucus, branchial oper- 

 cula, articulated filaments, and labial cirrhi or palpal 

 organs. 



Class 11. Myozoa, Rkinozoa, 



3351. Those Sarcozoa which for the first time obtain 

 true muscles and a perforated nasal organ are the 

 Eeptilia. 



3352. True muscles are red, have a definitely circum- 

 scribed outline, and are divisible into head, fleshy portion 

 or belly, and tail or tendon. As such they are found for 

 the first time in Reptiles. 



Thorax. 



3353. With the osseous system in Fishes the sexual 

 abdomen was chiefly developed ; with the muscular 

 system therefore, as in the present class, the abdomen 

 proper or intestinal abdomen becomes perfectly developed, 

 and the thorax more spacious in calibre. 



3354. The thorax is still blended with the abdomen. 

 In Fishes the disposition was already stirring to create for 

 themselves an air-organ ; only this was imperfectly 

 attained, since the swim-bladder communicated with 

 the gullet, but not with the branchial arches or larynx, 

 nor with the nasal organ, as in the present class. 



3355. Now, if the swim-bladder be symmetri- 

 cally developed, if it communicates with the branchial 

 larynx and opens through the nose, the aerial respiration 

 is completely attained, and shares its dominion over the 

 body along with the digestive function. 



