1S59.] On the Great Rorqual of the Indian Ocean. 493 



The skull of a ' Susu' from tbe Indus, presented by the late Sir 

 Alexander Burnes, is of a conspicuously distinct species, which I 

 designate 



Pl. indi, nobis, n. s. Maxillary crests wanting in the specimen. 

 Larger aud much more robust than Pl. gangetica, with the same 

 number of teeth which are more than twice as stout as in the other, 

 being much ground down by attrition in the specimen. Length of 

 skull 20i in. ; greatest width at zygomata 9^ in. ; depth of the two 

 jaws, with teeth in situhus, measured in the middle of their length, 

 3i in., — in Pl. gangetica barely If in. Length of symphisis of 

 lower jaw 11 in. Depth of zygomatic arch 2f in. 



A coloured figure of probably the identical individual that fur- 

 nished the skull above described occurs among the Burnes' draw- 

 ings. The rostrum is represented as short in proportion to the 

 length of the animal, and the neck to be more contracted than in 

 the Gangetic species, which may be an error of the draughtsman. 

 Colour also much paler, the lower-parts dull albescent, abruptly de- 

 fiued in a line from the gape to the tail-flukes. The specimen is 

 evidently female ; whence the male should have a longer rostrum. 

 The dimensions assigned are " 7 ft. long by 1 ft. 3 in. deep." Eudi- 

 mentary dorsal fin as in the Gangetic species. 



cimen. In what I believe to be the adult male, the symphisis of the lower-jaw 

 measures 17 in, ; in the adult female only 12 in. ; the rostrum being thus 5 in. 

 longer in the former. 



The ' Susu' ascends very high up the rivers, if not quite to the foot of the 

 mountains. Hardwicke's drawing was " made from a living specimen 1000 miles 

 above Calcutta." Major Tytier assures me that he has seen'them about 40 miles up 

 the Jumna, and also at Raj -ghat Mundi in the Dehra Dhoon. Likewise in the 

 Indus and Sutlej near Ludiana ; but these were doubtless of the species proper 

 to the Indus and its tributaries. The Gangetic ' Susu' is common throughout 

 the valley of Asam, in the Brahmaputra and its tributaries. Whether inhabiting 

 the Irawadi and other Burmese waters I am unaware ; but have been assured that 

 no such animal exists there. From the minuteness of its eyes, this creature is 

 obviously adapted for turbid rather than for clear water ; and it has never been 

 observed out to sea. It is migratory, as it occurs towards the Gangetic outlets 

 only in the cold season, as remarked by Dr. Cantor ; but at what particular season 

 it is observed in the Upper Provinces I have been unable to ascertain, 



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