VESPERTILIONID^E. CXC. 329 



566. PLECOTUS Geoffrey St. Hilaire. (TrXe/cco, to fold ; 

 ovs, ear.) 



a. Nostril without "rose-leaf" or disk-like appendage. (Corynorhinus 

 H. Allen.) 



1086. P. macrotis (Le Conte). BIG-EARED BAT. Blackish; 

 fur soft and long. L. 3J. E. 11. T. If. Va. to Dak. and S. 

 s, large ; ovs, ear.) 



ORDER LI. CETE. (THE CETACEANS.) 



Mammals of the sea, more or less fish-like in form, and adapted 

 for life in the open ocean. Bones of the neck short, more or less 

 fused ; posterior limbs wanting ; pelvis rudimentary ; anterior 

 limbs developed as broad, flattened paddles, without distinct fingers 

 and without nails. Nostrils developed as spiracles, and opening 

 usually on top of head, thus enabling the animals to breathe with- 

 out raising the head from the water; eyes small ; no external ear; 

 skin nearly or quite destitute of hair ; tail ending in a broad hori- 

 zontal fin or paddle ; back sometimes with a dorsal fin. Skin thick 

 and tough ; beneath it a thick layer of fat (blubber), which pro- 

 tects the animal from the cold. Species numerous ; found in all 

 seas, some of them being the largest of all animals. The nearest 

 relationships of the whales are perhaps with the seals, among living 

 forms, but the differentiation is now very wide. Of the numerous 

 species occasionally straying to our coasts, the following seem prop- 

 erly to belong to our fauna. The nomenclature and analysis of 

 genera is chiefly taken from True's paper on " Collecting specimens 

 of Cetaceans," in Rept. U. S. F. C. for 1883-1885. I have also 

 made considerable use of MSS. lists of species, kindly given me 

 by Mr. F. W. True, and by Professor Cope, (/c^ros, whale.) 



Families of Cete. 



a. Upper jaw without whalebone ; spiracles coalescent into one ; lower jaw 



much less thick than upper; skull unsymmetrical. (Denticete.) 

 b. Upper jaw with teeth (except in the adult of one genus); eye inserted 

 behind angle of mouth and not much above it; snout more or le* 

 sharp at tip; lower jaw with numerous (6 to 120) teeth. 



DELPHINHXE, 191. 

 bb. Upper jaw toothless; eye decidedly above angle of mouth. 



c. Lower jaw with 2 to 4 teeth, or apparently toothless; snout more or less 

 sharp at tip .............. ZIPHIID^E, 192. 



cc. Lower jaw with 18 to 50 teeth ; snout not sharp, sometimes truncate 

 at tip .............. PHYSETERIDJE, 193. 



aa. Upper jaw with long strips of baleen or whalebone ; no teeth ; spiracles 

 separate; eye very small, close to angle of mouth, between mouth and 

 pectorals; lower jaw very thick and deep, nearly as deep as upper, the 

 cleft of mouth curved. (Mystictte.) ..... BAL^ENID^E, 194. 



