1883.] PROF. FLOWER ON THE DELPHINID^. 489 



{Stenot) gadamu of Owen', described from a mutilated skull and 

 a native drawing of a specimen taken at Vizagapatam (Madras) in 

 1853. The skull is now in the British Museum ; it is that of a 

 young animal. The pterygoids are widely divergent. The rostrum 

 is wider and more depressed than in I), sinensis ; the premaxillse 

 especially are of a peculiar form, being narrow at their upper third 

 and enlarging at the middle of the rostrum, where they are both 

 more elevated and wider than in other species. The teeth are 

 iSI according to Owen. A more complete skull of the same species, 

 from Australia, has been recently added to the Cambridge University 

 Museum. 



B. lentiginosus, Owen, from the same locality, described in the 

 same memoir, is a closely allied species, if distinct. 



Delphinus j)lumbeus, Dussumier, in Cuvier's ' llegne Animal,' 

 2'' edit. t. 1, p. 283 (1829), according to the skull in the Paris 

 Museum, figured by Gervais (Osteographie, pi. xxxvii.), represents 

 the longest and narrowest form of this type, with the most numerous 

 teetli, viz. '—, only 4 mm. in diameter. The pterygoids are very 

 characteristic. It is a large species, the skull measuring 550 mm. 

 in length. This has been conjecturally identified with D. malayanus. 

 Lesson (Voy, de la Coquille, Zool. p. 184, pi. ix. fig. 5 (1826), 

 from external form only). 



Lagenorhynchus. 



Lagenorliynchus, Gray, Zool. Erebus & Terror, p. 34 (1840). 



The following characters appear to be common to all the animals 

 of this section of which the complete osteology is known : — 



Cranium without grooves on palate, llostrum scarcely exceeding 

 the length of the cranium, broad at the base, and gradually tapering 

 towaids the apex, depressed. The pterygoid bones rather short and 

 broad, united iu the middle line (see fig. 8, p. 490). Symphysis of man- 

 dible short. Teeth small, not exceeding 4 mm. in diameter, not numer- 

 ous, 23-33. Vertebrte very numerous, 80 to 90. Spinous and trans- 

 verse processes of the lumbar vertebrae very long and slender. Manus 

 with broad, flattened metacarpals and phalanges, with parallel borders. 



The skulls of the species assigned to this group vary considerably 

 in form. L. albirostiis especially deviates from the others in the out- 

 line, as seen from above, being more regularly pfiar-shaped, an a|)- 

 pearance caused mainly by the anteorbital prominences of the maxilla, 

 frontal and jugal, which stand out on each side behind the notch, 

 being softened off and the rostrum tapering gradually to a sharp 

 apex ; while in L. electra (also a large species) the prominences are 

 more strongly develoi)ed, and the rostrum is more obtuse at the apex. 

 The smaller L. acutus and L. clanculus are somewhat intermediate, 

 the former, however, inclining strongly to the electra type, the latter 

 to that of albirostris. 



Gray appears to have recognized this difference, although, as 

 usual, not defining it clearly, for in the 'Synopsis' (1868) he places 

 ' Trans. Zool. Soc. vol. vi. p. 17- 



