DR. J. MUEIE ON THE ORaANIZATION OF THE CAAING WHALE. 239 



abdominal region. Some, however, attribute to this black colour a shining lustre, 

 " like oiled silk," which G. Cuvier' defines as ffris noirdtrc. In the specimen dissected 

 by me, the head, bodv fins, and tail were decidedly of a black hue. When the surface 

 of the skin was moist it possessed an appearance which might be compared to the 

 outer polish of fresh india-rubber ; but as the integument dried it assumed more of a 

 lamp-black or sooty tint. This variation in shade, there can be no doubt, was attributable 

 to the reflection or partial absorption of the rays of light, according as the superficial 

 layer of the cuticle was wet or dry. A similar alteration in depth of tint has been 

 observed by Heddle^ and myself as occurring in the genus Physalus. I have suggested, 

 as a partial explanation of the phenomenonS that the epidermis, readily separable into 

 superimposed delicate layers, allows, under certain conditions, less or more of the sub- 

 jacent pigment to predominate. 



As remarked by the various writers, Oloblocephalus melas (=G. svineval, Gray) is 

 characterized by having a long posteriorly narrowed white stripe upon the abdomen. 

 This commences at the hinder end of the throat, and widens in the pectoral region in a 

 kind of heart-shaped or partially cruciform manner ; thence it gradually narrows as it 

 goes backwards on the abdomen, and finally terminates in a point a little in advance of 

 the genital fissure. In these respects our specimen agreed. I had intended to have 

 figured this abdominal view, as Baron C'uviers illustration in the ' Annales'^ is rather 

 deficient in clearness, but my chance was frustrated by my assistants partially flensing 

 the belly during my temporary absence. 



It is noteworthy that the dark colouring of the sides of the body shades by an inter- 

 vening olive-green and grey tint into the yellowish rather than pure white of the 

 abdomen. This assimilation of the extremes of colour by neutral or median tints, is 

 the same which obtains, but with more mottling, in the Common Porpoise. 



I believe Cetaceans, like other animals, vary within certain limits according to age 

 and sex. The general outward conformation of this female might not inaptly be com- 

 pared to a club with three outstretched falcate processes (dorsal and pectoral fins) 

 abreast of its middle, and a semilunar transverse keep (the tail) at the narrow or handle 

 end. This fancied resemblance to such an instrument is no mere stretch of the imagi- 

 nation, as the bird's-eye dorsal view (fig. 2) more especially certifies. In the lateral 

 aspect of the body (fig. 1) the snout is seen to be very globose and prominent; hence 

 Cuvier's term Glohiceps. This protuberant swelling projects vertically nearly as far as 

 the upper lip, a wide shallow sulcus, however, intervening. 



The mandible and its dense labial covering are shorter than the premaxillary portion 



angustis: rostro obtuso: maxilla superiore prEeclinante : dentibus acutis conoideis panim incurvatis" (Nichol- 

 son's Journal, 1809, xxii. p. 83). 



' Ann. du Mus. d'Hist. Nat. t. xix. p. 3. ' P. Z. S. 185G, p. 193. ' P. Z. S. 1865, p. 207. 



' See also a remark thereon by Professor Turner in Balcenoptera sihbaldn {I. c. p. 203). 



' i.e. pi. l.figs. 2(d')and3(?). 



