DR. J. MURIE ON THE ORGANIZATION OF THE CAAING WHALE. 287 



nodule of cartilage tipping either end, that rearwards was very distinct. No osseous or 

 ligamentous cross bai-, representing rudimentary femur, existed, such as is met with 

 in Balu'na and Balcenoptera. The smooth or only slightly roughened bone rather 

 resembles the pelvis of the northern Orca. 



Uniting the opposite pelvic elements was a strong X -shaped glistening fascia, fixed 

 within a trifle of the whole length of the inner concave border of each bone. A 

 number of muscles were attached, partly to this and to the bones themselves, and 

 bloodvessels penetrated the two latter, which I have already referred to. 



The muscular structures attached to the pelvic bones, and surrounding the generative 

 outlet of Cetaceans, have heretofore been but imperfectly studied and figured. The 

 pains-taking Stannius, in his "Myology of the Porpoise"', admits of anal and pelvic 

 muscles the following : — a sphincter ani, an ischio-cavernosus, and a retractor ischi or 

 ischio-caudalis. I believe no other author has stated there are more, though others are 

 inferred to exist^. In my researches on this female Deductor and other Whales, I 

 have been fortunate in meeting with many more than the above ; and these I shall 

 describe in layers, from the superficial to the deep, as dissected {vide figs. 76 & 78 in 

 my last Plate). 



In a study of the parts it is well to keep in mind the sex. 



I have already {antea, p. 272) alluded to the inferior and posterior (pudendal) portion 

 of the panniculus carnosus, shearing outwards and leaving the tail free ; but there is, at 

 the same time, a certain continuity with it of a thin superficial layer of transverse fibres. 

 These of opposite sides form a long ellipse, whose apex anteriorly meets the divergent 

 angle of the panniculi, partially cover the rectus abdominis and other genital and 

 mammary gland-muscles, whilst posteriorly it reaches the perineal raphe and anal 

 sphincter. It acts as a dilator of the vulva, whilst the portion continued to the anus 

 serves as an anal protractor. This muscular sheet altogether appears to be the homo- 

 logue of levator ani and probably combined superficial transversus perinei of human 

 anatomy. I may as well mention that in the perineal region of Risso's Grampus, 

 beneath the cross fibres of the levator ani, I observed a narrow oblique band of muscle 

 which passed from the surface of the pubo-ilio-coccygeus to the perineal raphe. This 

 slip doubtless would represent a superficial transversus perinei. Moreover, in the same 

 female specimen, I noticed another short, broadish, fleshy band, which ran obliquely 

 from the surface of the rectus abdominis, at the commencement of its posterior tendon, 

 inwards towards the fore part and side of the clitoris. Its superficial position and 

 inguinal relations suggest its being a homologue of a cremaster, though such an 

 anomaly in the female sounds strange. 



' MuUer's ArcHv, 1849. 



' Professor Van Beneden has been kind enough to put in my hands a short paper of his, " De la Com- 

 position du Bassin des Cetaces," Bull. 2 ser. t. xxv. Therein he faithfully figures and describes the generative 

 organs of Deljphinus tursio, noting two muscles, viz. ischio-cavernosus and retractor of penis. 



