1870. ] LANKESTER—NEWER TERTIARIES OF SUFFOLK. 505 
The superror surface of this specimen does not present the complete 
pair of grooves which run along the superior surface in Belemno- 
ziphius, enclosing between them a central vomerine area; nor, like 
typical Choneziphius planirostris, does it present a bifid structure in 
the presence of a central groove stretching from the orifice of the 
vomerine canal; on the contrary, the curious projection of the 
anterior end of the rostrum (which is paralleled in some specimens 
of Belemnoziphius) overhangs and conceals the vomerine canal, and 
the surface is perfectly smooth, neither indicating the junction of 
the intermaxillaries by a median fissure, as in Choneziphius plani- 
rostris, nor allowing the vomer to appear between those bones, as in 
Belemnoziphius. ; : 
The large unsymmetrical fossee excavated in the expanded por- 
tion of the intermaxillaries at the posterior part of the specimen lead 
into short grooves, which run forward on the surface and soon 
dwindle away (Plate XXXIII. fig. 2, 2g and rg). These are iden- 
tical with the grooves demarcating the vomerine tract in Belemno- 
ziphius; but here they terminate rapidly, as in Choneziphius, by 
the junction of the intermaxillaries in the middle line. They are 
present in Choneziphius planirostris, which has similar fosse to those 
seen in this specimen; but in Cuvier’s first specimen the grooves are 
for a short space converted into canals, whilst in another specimen 
of Choneziphius planirostris, of which there is a cast in the British 
Museum, the canals are as open as in this specimen. 
Generic position and species—The rostrum under description 
clearly does not belong to Professor Huxley’s genus Belemnoziphius, 
which is remarkably well characterized not only by the solidity of 
the rostrum, the complete exposure of the central vomerine area 
(which Professor Owen, differing from Cuvier, Duvernoy, Gervais, 
and Van Beneden, terms prefrontal), but also by the two obvious 
perforations placed near the middle line in the intermaxillaries on 
the anterior wall of the nasal fossa marked aa by Professor Huxley 
in his figure of Belemnoziphius compressus. 
The series of canals in Belemnoziphius and Choneziphius differ in 
avery marked manner; but it is not possible to determine their 
exact relations without detailed comparison, and perhaps cutting 
specimens. Recently in Paris I had the opportunity, by the kind- 
ness of M. Gervais, of examining carefully the rostra of Cuvier’s 
types of Z. planirostris and Z. longirostris. Z. longirostris (Belemno- 
ziphius) comes very near to the Seychelles Zphius (M. densirostris), 
and differs remarkably, as do all our Crag Belemnoziphi, from Cho- 
neziphius in the absence of the large unsymmetrical fosse seen in 
the latter genus, and in the presence of the sharply marked orifices 
leading into a canal (a a of Huxley’s paper), which is absent in the 
other. Professor Owen marks these structures as identical in his 
recent monograph; but they have a distinct character, though 
possibly related in origin. It is not possible to fully compare the 
canals of Belemnoziphius with those of Choneziphius, on account of 
the loss of the expanded portion in all specimens of the former genus. 
The specimen which best shows the proximal part of the rostrum of 
VOL. XXVI.—PART I. 20 
