358 



CETACEA. 



Genus Orcella, Gray. 

 * Orcella eluminalis, Andr. Plate XXV ^. 



Dolphin o£ the Irawady, Andr., Proc. ZooL Soc. 1870, p. 220 et p. 544. 



Orcella jluminalisy kvAx. 1871, Proc. Zool. Soc, pp. 143-4, fig. 2; Blyth, Journ. As. Soc, vol. xliv. 

 ex. no., 1875, p. 34. 



The specimens which form the subject of this Memoir belong to the male 

 sex. The first was found in a partially decayed condition by Captain Bowers on 

 a sandbank at Bhamo. Decomposition, however, had not progressed so far as 

 to render the skin unfit for preservation. He therefore had the carcass preserved 

 in a mixture of spirit, salt, and arsenic, and had it forwarded to Calcutta, 

 a distance of nearly 2,000 miles. When it reached its destination the skin was 

 intact, although the epidermis had peeled off, but the muscles and viscera 

 were much decayed; still I was enabled to take the following measurements of 

 the specimen and to draw up a brief description of its external characters. 



The general form, so far as I could make out from this then unique example, 

 was the same as that of O. brevirostris, Owen. The fresher specimens afterwards 

 obtained enabled me to determine that the species differs from 0. brevirostris in its 

 rather smaller, lower, and more falcate dorsal fin, its more pointed and less anteriorly 

 bulging head, and rather shorter and broader pectoral fins : the colour in both is 

 much alike, being pale slaty above and whitish on the under parts/ but the skin of 

 O. fluminalis is streaked somewhat as in BissVs dolphin.^ 



Measurements of the first male, Orcella fluminalis, obtained by Captain Bowers. 



From tip of snout to fork of tail along the side 

 „ „ „ to dorsal fin following back curve 



Length of the dorsal fin .... 



Tip of snout to base of pectoral flipper . 



Length of pectoral flipper along anterior margin 

 „ „ „ „ posterior „ 



Caudal flipper along its anterior margin 



Snout to the blow-hole on the forehead 



Transverse diameter of the blow-hole 



Snout to anterior margin of genital slit 



Length of the external genital orifice 



Distance between genital slit and nipples 



Nipples apart from each other 



Distance between the nipple and anus 



Length of the gape 



Snout to anterior angle of eye 



Longitudinal diameter of the eye 



From the eye to the ear-hole 



Diameter of the external aural orifice 



Girth over the blow-hole 



Inches. 



90-00 



55-75 



4-75 



18-75 



17-00 



11-75 



1300 



10-00 



1-50 



52-75 



1-75 



5-00 



0-75 



2-50 



5-75 



8-00 



075 



3-76 



0-12 



28-25 



^ In the Proc. Zool. Soc. Lond. 1871, p. 144, I stated on the authority of Captain Bowers that the colour was uni- 

 form dirty white, but repeated views of these dolphins in my late journey up the Irawady convince me that the colours 

 mentioned above are those natural to it. 



* Flower, Trans. Zool Soc, vol. viii, 1872, p. 3. 



