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PLATE XXV. 



Fig. 1. The Susu or Gangetic Dolphin Flatanista gangetica, Lebeck. Drawing taken 



from photograph, the reduction being about ytth the natural dimension 



of the animal. 

 „ 2. Aperture of the blow-hole of the same specimen ; \ natural size. 

 5, 3. Right ear-slit or external auditory foramen of Flatanistay enlarged twice 



natural size. 

 „ 4. The short-snouted Orcella, 0, brevirostris, Owen. 

 5, 5. Reduced outline of the head of 0. hremrostris viewed from above, showing 



the blow-hole placed slightly to the left of the median line ; also the 



lateral prominences of the eyes. 



PLATE XXVa. 



Fig. 1. Dolphin of the Irawady, Orcella fluminalis, Anderson. Drawing taken 

 of a male specimen captured near Bhamo, June 1876. Reduced -^th 

 natural size. 



5, 2. A bird's eye or dorsal view of the same animal, also -Jth natural size. 



„ 3. A transverse section through the trunk of the male 0. flummalis^ cut in a 

 vertical line with the pelvic bones. Reduced. 



The lettering applies as follows : — m, Z., mesial line of back ; «., skin ; 

 Z>., blubber; 5.^., spinous process of vertebra; c, centrum; ^., transverse 

 process ; m., muscles of upper and lower parts of body; pp.^, right and 

 left pelvic bones ; r., rectum cut through ; c. c, c, c.^, commencement of the 

 right and left corpora cavernosa ; c.s,, corpus spongiosum near commence- 

 ment ; r,p,i the retractor penis muscle cut across ; /., fibrous connections 

 of the corpora cavernosa and attached to the pelvic bones. 



„ 4. The right pelvic bone of Orcella fluminalis viewed on its under aspect and 

 drawn of natural size : a., anterior end of bone ; p,, posterior extremity ; 

 i., inferior aspect ; a.p.^ place of attachment of penis. 



PLATE XXVI. 



Fig. 1. A front or ventral view of the opened cavities of the stomach of Flatanista ; 

 the passages between being indicated by curved bristles : oe,, oesophagus ; 

 J, ZZ, 177, IV^ cavities in sequence ; d., duodenum. Reduced Jth natural 

 size. 

 „ 2. A small portion of the mucous membrane of the first gastric chamber of 

 the foetal Flatanista, Of natural size, showing the convoluted mucous 

 folds. 



