ORCELLA. 359 



Inches. 



Girth just in front of pectoral flippers 3925 



„ half-way hetween flippers to genital aperture 41 '50 



,, round the anal region 28'00 



„ at the base of the tail 9 00 



Measurements of the second male, obtained by Ca'ptain Cooke at Bhamo, July 1876. 



Inches. 



Tip of snout to notch of tail along the side 86'05 



„ „ to middle of dorsal fin along the side 49'00 



Tip to tip of caudal flippers 241)5 



Length of pectoral flipper in straiglit line along centre lo'OO 



Greatest breadth of pectoral flipper . . .... ..... 6'05 



Tip of snout along curve of head to centre of blow-hole lO-QO 



Transverse breadth of blow-hole 1-05 



Basal length of dorsal fin ' g-QO 



Length of dorsal fin from base anteriorly to tip posteriorly 6'05 



j> » i> )) jj to centre of notch ....... 6'00 



Depth through centre 2'07 



Angle of mouth to anterior angle of eye .......... 1'08 



Length of gape along upper jaw 5-06 



.. of eye O'O? 



Posterior angle of eye to ear . ... ......... 3'01 



Tip of left horn of blow-hole to angle of mouth along curve of head 7-00 



„ on right side 7-08 



„ of left horn to left of mesial line of back l-QO 



„ of right horn to right of „ „ 1-05 



„ of left anterior to right horn 005 



Centre of anal orifice to notch of tail along ventral surface 23'08 



)) „ „ to middle of mammary slit ......... 3'04 



„ of mammary slit to posterior margin of genital slit . . . . • . . . 3-06 



Length of mammary slit 008 



Distance (transverse) between mammary slits 0'25 



Length of pelvic bone, left side 209 



Anterior end of pelvic bone distant from chevron bone of 16th lumbar vertebra . . . I'Ol 



,) „ ,, „ „ from centrum of 16th lumbar vertebra .... 2'05 



„ extremity distant from external surface 3-00 



Posterior „ „ „ „ 105 



Anterior „ of pelvic bone nearer to the mesial line than the posterior end . . . 0'25 



Distribution. — It is a remarkable circumstance that this dolphin has never yet 

 been observed in those j)ortions of the Irawady under the influence of the tides, 

 {see Map), which would seem to indicate that it is more strictly fluviatile than even 

 Platanista. On the two different occasions I sailed up the river from Rangoon 

 to Bham.6, my upward voyages were made in the months of December and 

 '^ January, and I retiu'ned in the months of Sej)tember, October, and March, so 

 that my observations have extended over nearly five months, embracing those 

 periods when the river was at its highest and at its lowest level. On these 

 occasions I had the question of the distribution of the Irawady dolphin steadily 

 before me, and took the precaution daily to appoint certain of my Zoological 

 collectors to observe, in our upward progress, the first appearance of tliis Cetacean, 

 besides giving a considerable portion of my own time to the observation. In 

 no instance have I seen a single example of this dolphin in the delta of the 

 river ; the lowest point at which I saw it on my first visit was in the deep 



