PLATAKISTA— INIA. 05 



5. Tympanic bones, pair of, also a single right bone. Length 

 2 inches, breadth IJ inch, height 1^ inch Outer sur- 

 face with narrow groove for division into two flattened 

 prominences, almost ecpial in length ; lip-shaped pro- 

 cess thickened, prolonged down outer surface. Inner 

 surface | inch in its posterior two-thirds, then rapidl}' 

 diminishing to pointed end. Bilobed; a groove ex- 

 tends forward along the greater part of the inferior 

 surface and contains a rough ridge f inch long ; the 

 surface ends in a pointed process, above which is the 

 Eustachian opening. See figure below. 



6. Head, sagittal section of a 3"oung male, showing the brain 



in situ. The beak has been removed. 



Donor — Dr Nelson Ainiandale. 



7. Caudal fin of a young male, showing the mesial notch in 



the posterior border. Donor — Dr N. Annandale. 



8. Pectoral limbs, pair of, young male, showing the form and 



the truncated free end. The proximal row of the 

 carpus consists of radiale {r), which may be separate 

 or fused with carpale i., of intermedium {in), the ulnare 

 being absent ; the distal row has Carpale^, C.,, Cg, C^+5 ; 

 a centrale is also present ; the digits are as follows : 

 MPh., for pollex, then MPh^, I\IPli„ MPh, and MPh, 

 for minimus. X-ray photos figured by Turner in Proc. 

 Roy. Soc. Edin., vol. xxx., 1900, along with other 

 varieties of the manus in Platanista. See Plates 

 XL, XII. Donor — Dr N. Annandale. 



II. INIA. (In.) 



Inia, D'Orbigny, N. Ann. Mus. Paris, iii., 1834. 



Only three lumbar vertebrae. Sternum a single 

 segment. Maxillary crests small, dorsal fin rudi- 

 mentary, palatines separated by vomer, very long 



