ART. 13 ANATOMY OF CHINESE FINLESS PORPOISE HOWELL. 19 



are features of the latter that are somewhat difficult to reconcile with 

 the anatomy of the Cetacea as reported by others, and the descrip- 

 tions are far from complete, while the anatomy of Balaenoptera^ this 

 being a whalebone whale, is very different in many respects from 

 NeoTtieris. In addition, certain muscles of Phocaena (Stannius, 

 1849) are compared, while the work on Balaenoptera by Carte and 

 McAlister (1869) is mentioned occasionally. In the following pages 

 these papers are usually referred to by the names of the genera con- 

 cerned — seldom by the authors. 



It should be mentioned that there is probably considerable indi- 

 vidual variation of certain myological features. Thus, direct com- 

 parison showed much difference in size of the superficial masseter in 

 the two specimens dissected, while the mastohumeralis was small 

 in the second, but was recollected as being considerably larger in the 

 first individual examined. 



After removing the integument it is found that the blubber may 

 be as much as 25 mm., but for the most part is usually 15 or even 

 10 mm., in thickness. It is practically absent from the lateral 

 peduncle, the flippers, and the sides of the head. Beneath the 

 frontal prominence is a deposit of soft, spongy fat from which the 

 oil runs when this region is pressed with a finger. This is about 

 50 mm. in thickness and is roughly cylindrical, with bounds illy 

 defined. Above the rostrum, too, there is much fatty tissue, but 

 of tough, spongy consistency. Conspicuous throughout the blubber, 

 especially of the sides, are many large lymph vessels. 



A noteworthy characteristic of the musculature of this, and very 

 likely all cetaceans, is the fact that in many areas the muscles are 

 not attached directly to the bones, but rather to a tough membrane 

 which invests the bone more or less loosely. Such a membrane covers 

 most of the occipital region of the skull, especially about the exoc- 

 cipitals, the entire scapula, the ribs, and portions of the vertebrae are 

 so sheathed. In modified form it occurs upon the hyoid, but not 

 the humerus. 



The ycuwnieulus cm^osus is complicated. As in most if not all 

 cetaceans, there is a tendinous raphe (although it seems sometimes 

 to have been overlooked) extending caudo-dorsad from the caudal 

 border of the flipper, it being clearly distinguishable as such for at 

 least 200 mm. Into this raphe are inserted muscle fibers with a 

 slight cranial inclination running both from the dorsal and the 

 ventral regions. Upon the anterior and central thorax the fibers 

 are not distinguishable until quite well ventrad toward the flipper, 

 but slightly farther caudad they extend from the middorsal line. 

 Here, however, there is interruption of the continuity of the fibers 



