170 Prof. Eschricht on the Gangetic Dolphin. 



perhaps in most toothed whales. In the Hog tribe this pair of 

 bones has been very long known as peculiar to it, and usually 

 called the prenasal bones, which may always be easily recognized 

 in the porpoise, as a minute, fixed, vascular bone, placed anteriorly 

 in each nostril, close to the septum (exactly where it is found 

 in the Hog tribe). In the Delph, globiceps it is somewhat larger. 

 This pair of bones, which might perhaps be more express- 

 ively called ossa narium, I also found in our dolphin, as a small 

 ossification in the dried cartilaginous covering of the nostril, 

 on each side. The vomer in whales grows gradually upwards, 

 not only before the anterior part of the sphenoid bone, but also 

 before the ethmoid, of which, however, a projecting part con- 

 tinues mostly uncovered (namely that surface which in man is 

 the lowest of the horizontal portion) between the vomer, and 

 the above-mentioned little osseous plate of the lowest third of 

 the nasal bones, or perhaps (in the Gangetic dolphin) the nasal 

 bones themselves (PI. VII. fig. 2v,v). 



The upper jaw projects, as in other dolphins, beyond the 

 frontal bones, in such a manner, that these (PL VI. fig. 1 f,f,f) 

 are uncovered only in the shape of a small, curved, bony promi- 

 nence, bounded near the median line, which is pushed strongly 

 to the left side, by the nasal (n, n), the intermaxillary (i), and the 

 upper jaw-bones (m, m) ; behind, by the last-mentioned and the 

 occipital bone (o) ; but laterally disappearing in the long pro- 

 cessus orbitales ; the frontal bone on the right side (/) protruding 

 in one place like a wedge. M. Cuvier observes [loc. cit. p. 298) : 

 "Le caractere le plus frappant de cette tete, c'est que les 

 maxillaires, apres avoir recouvert comme dans les autres dau- 

 phins les frontaux jusqu'aux cretes temporales, produisent 

 chacun une grande paroi osseuse *, qui se redresse et forme une 

 grande voute sur le dessus de I'appareil ejaculateur des narines. 

 A cet effet, Pune de ces productions osseuses se rapproche de 

 Pautre, et paroit ineme la toucher sur les deux tiers anterieurs ; 

 mais en arriere elles s'ecartent pour laisser passage k P event. 

 C'est la ligne de reunion de ces deux parois osseuses qui soutient 

 la carene que le front de cet animal montre a Pexterieurf. En 

 dessous, ces parois offrent plusieurs cavites ou une espece de 

 reseau forme par des branches osseuses tres multipliers. Dans 

 Panimal frais, la plus grande partie de Pespace qu' elles couvrent 

 est remplie d'une substance fibreuse, serree et assez dure." 



I may add to this very graphic description, that the " cavities 

 on the lower part of these bony walls " do in reality (see par- 

 ticularly PI. VII. fig. 2) by no means occupy the inner side, 

 but lie within the osseous walls or crests themselves, that is, 



* Tab. 1. f. 2, tab. 2. f. 1, & tab. 3. f. 2. f Tab. 1 . f. 2. 



