450 ilK. K. T. NEWTON ON NEW MAMMALS EROM 



the front of the rostrum as that which is seen in Mr. Canham's 

 example, and he is no doubt right in regarding it as a new 

 species. 



7. MEsorLODON scAPHOiDEs, sp. uov. (PI. XVLTI. figs. 8 «, 8 b.) 



The Ziphioid rostrum from the nodule-bed of the Red Crag, near 

 Woodbridge, now to be described is preserved in the Museum of 

 Practical Geology, and is one of the most aberrant forms yet 

 known from this deposit. The rostra hitherto described from the 

 Red Crag are more or less elongated forms, some being very long 

 and attenuated; the present specimen, however, is remarkable for 

 being extremely short and proportionately deep, When seen from 

 above (fig. 8 a), it has the form of a triangle, the hinder part 

 forming an irregular base, about three inches wide ; and the sides 

 passing almost straight to the front to meet in a sharp edge. 



The greatest length of this specimen is about five and a quarter 

 inches. In a side view (fig. 8 6,^ nat. size) the hinder part is 

 seen to be about one inch and three quarters deep ; but it increases 

 anteriorly to about two and a quarter inches ; the front margin 

 curving u])wards like the prow of a boat. The mesethmoid is 

 completely ossified, and in a back view its outline is clearly defined : 

 its hinder end having a deep fossa which may have lodged the front 

 of the internasal septum ; its lower margin is received into a trough 

 of what is doubtless the vomer. Anteriorly the vomer itself seems 

 to be covered in by downward processes of the maxillai ; but all the 

 bones of the front part of this rostrum are so completely coossified 

 that the divisions between them are entirely obliterated. At the 

 hinder part of the upper surface there are some indications of a 

 division between the mesethmoid and the premaxilbe ; also on the 

 right side there is a line which may indicate the junction of the 

 hinder part of the maxilla and premaxilla. 



On the upper surface posteriorly are the apertures of two 

 large, covered canals, which evidently correspond with those 

 in Professor Huxley's figures of Belemnoziphius compressus *, 

 marked with the letters a, a. On the right side the covering is 

 broken away, but it is retained on the left. These canals, passing 

 downwards and forwards, soon become open channels, running 

 along the sides of the prem axillary region, and turning a little 

 upwards they become wide and shallow at the front of the rostrum. 

 If one of these premaxillary canals, as they may be called, is 

 followed backwards under the bony covering, it will be found to 

 bifurcate ; one of the branches passing upwards and backwards is 

 the canal already noticed, which issues at the aperture, and 

 may be further traced as a shallow depression passing backwards 

 over the premaxilla : the second branch is directed downwards 

 and backwards, and after a short course opens, fig. 8 &, into 

 a large cavity, partly preserved on the right side (seen in 

 fig. 8 h), but better defined on the left. Prom each of these 



* Quart. Jouru. Geo!. Soc. vol. xx. ])1. 19. 



