504 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 25, 
of fracture, a pair of canals (four in all). One of these canals (Pl. 
XXXITI. figs. 2, 3, & 4,77) (on each side) is a little wider than a 
common lead-pencil and is exposed at the extreme lateral points of 
the rostrum, running thence downwards and forwards for a few 
inches, when it receives the other canal (the two sides corresponding), 
which is smaller and has a superior position (s/). The smaller 
canal has its posterior termination (caused by fracture which has 
destroyed more of the left than of the right of these smaller canals) 
within an inch and a half of the median line and on the superior 
part of the specimen, so that it 1s not impossible that the canals 
a,a, of Huxley (‘On a New Cetacean,” Quart. Journ. Geol. Soe. 
vol. xx. pl. xix., 1864) are represented by this pair. The course 
of each small canal is forwards, outwards, and downwards to meet 
the larger lateral canal, which it jos at an acute angle. After 
the junction of the smaller postero-superior canals with the large 
lateral canals, these continue to run forwards and inwards, as a lueky 
split in the specimen, which allows a piece of the rostrum to be 
removed, enables one to see, with regard to the left side; their ulti- 
mate course is not, however, traceable. At the point where the larger 
canal receives the smaller one on this broken side, four slightly 
diverging smaller canals are given off, which run forward in the sub- 
stance of the rostrum and probably transmitted vessels; one of these 
occupies the position in which Prof. Huxley describes a lateral 
groove finally becoming a covered canal in Belemnoziphius, viz. along 
the line of the lateral ridge which marks off the maxillary from the 
intermaxillary region of the rostrum. In this specimen the canal of 
neither right nor left side becomes a groove externally ; but that on 
the left side has a small terminal opening anteriorly, though none can 
be traced on the right side. Some of these small branches of the large 
lateral canals, in a measure, represent the pair seen in the trans- 
verse section of the anterior portion of the rostrum of Belemnoziphius 
(see Prof. Huxley’s fig. D), which are also present and open exter- 
nally in Choneziphius. How far this system of canals agrees with 
those of the Choneziphius planirostris of Cuvier it is impossible to 
say, without examination and perhaps section of actual specimens, 
since the cast in the British Muscum of a specimen (not of the 
original, which is preserved at Paris) does not show either the 
canals or their orifices. The two fragments of Choneziphius in the 
British Museum, from Suffolk, are not sufficiently perfect to be of use. 
The longitudinal fracture of the left side of the rostrum, which 
shows something of the disposition of the canals in the middle part 
of their course, also demonstrates the solidity and density of the 
structure. It further shows that the keel, described as marking the 
posterior third of the inferior surface, is continuous with a central 
mass of bone reaching forward from it, and from which the detached 
piece has become separated along a kind of surface of anchylosis. 
This central ridge, appearing posteriorly as the keel, is the vomerine 
constituent of the rostrum, which is closely embraced by the maxil- 
laries and intermaxillaries, welded and soldered to it without any 
superficial indication, such as a suture or groove. 
