266 CRT ACE A 



of the secretions of the second, or true digestive compartment 

 (c). This, which is much smaller than the first, has very thick 

 walls, the mucous membrane being filled with numerous tubular 

 glands. The surface of this membrane is smooth and soft, 

 being thrown into numerous folds, which in this genus are arranged 

 in a very peculiar and characteristic manner, so as to form a 

 series of prominent longitudinal ridges, each of which sends off 

 short lateral ridges at right angles to itself, which interdigitate 

 with those proceeding from the next longitudinal ridge. The 

 remainder of the stomach (d to /) may be compared to the pyloric 

 antrum of the stomach of ordinary mammals. It is elongated, 

 cylindrical, and intestiniform, with a smooth lining membrane, 

 sharply bent upon itself, and terminating in a very small cir- 

 cular pyloric aperture (/). In the Porpoise the commence- 

 ment of this cavity is constricted off from the remainder, so as to 

 form a small globular sac. In most Dolphins (as Tursiops, GloU- 

 cepJialus, and Grampus) there are two such small sacs of very similar 

 size and form, communicating by circular pylorus -like apertures ; 

 and in Hyperoodon the whole compartment is divided by a series of 

 constrictions into as many as seven separate cavities, which have 

 been regarded as distinct stomachs. Immediately beyond the 

 pylorus the duodenum has a globular dilatation, as in the camels 

 and some other Ungulates, into the lower end of which the biliary 

 duct (h) enters. 



An allied species, differing mainly in the absence of dorsal fin, 

 and in the teeth (with the same form of crown) being fewer in 

 number and of larger size, called Delphinus pJwccenoides by Cuvier, 

 D. melas by Schlegel, forms the type of Gray's genus Neomeris. 1 

 It is rather smaller than the Common Porpoise, and almost entirely 

 black in colour. Common off the coast of Bombay, it has been 

 met with in other parts of the Indian Ocean, and near J.apan. 

 The British Museum recently received a specimen taken in the 

 Chinese river Yang-tse-kiang nearly a thousand miles from the 

 sea, which only differs from others from India in wanting a patch 

 of small horny tubercles on the back. As such tubercles are 

 present or absent in otherwise similar individuals of P. communis, it 

 is doubtful whether they can be regarded as constituting a specific 

 character. 



Cephalorhynchus* Rostrum as long and sometimes slightly 

 longer than the cranial portion of the skull. Pterygoids widely 

 separated from one another. Teeth small (less than 3 mm. in 

 diameter), f 4 to f. Vertebrae : C 7, D 13, L 15, C 30 ; total 65. 

 Dorsal fin low, obtusely triangular or rounded. Pectoral fins rather 



1 Zoology of Erebus and Terror, p. 30 (1846). The name is preoccupied by 

 Lamarck for a genus of Polyzoa (1816). 



2 Gray, Cat. Cetacea Brit. Mus. p. 106 (1850). 



