32 ELEMENTS OF COMPARATIVE ZOOLOGY. 



form a solid box. In the sunfishes, which may weigh 

 500 Ibs., the body is almost circular in outline, and has a 

 distinctly chopped-oif appearance. As a whole, the order 

 bears most resemblance to the Acanthopteri. None are ol 

 the slightest economic importance. 



ORDER VI. LOPHOBRANCHII. 



These are the most aberrant of bony fishes. The gills, 

 as the name implies, are tufted, and composed of small 

 rounded lobes packed in the gill-chamber. The opercular 

 apparatus is reduced to a simple plate, the small, toothless 

 mouth is at the end of a long snout, the skin is covered with 

 bony plates arranged in rings around the body. The 

 species, which are all small, are known, from their fanciful 

 shapes, as pipefishes and sea-horses. Many have a remark- 

 able peculiarity in breeding habits, in that the young are 

 carried for a time in a pouch beneath the tail of the male. 



COMPARISONS. 



Prepare another sheet as before, with columns for bony 

 fish and dogfish, and give answers to the following ques- 

 tions : 



(1) Where does the animal live? (2) Is the surface 

 naked or scaly? (3) Is there a skeleton to the median 

 fins ? (4) Is there anything which could be called a hand 

 or foot? (5) Do the nostrils connect with mouth or 

 throat ? (6) How does the animal breathe ? (7) How 

 many auricles and ventricles to the heart ? 



