448 MR. E. T. NEWTON ON NEW MAMMALS EROM 



provisionally include the incisor tooth from the Norwich Crag of 

 Sizewell Gap, near Southwold (fig. 6), alluded to by Sir E. Owen 

 as '' Beaver " *. This incisor, preserved in the Society's Museum, 

 has the front rounded and its enamel rugose, thus agreeing with 

 Trof/ontherium and not with Castor. 



6. Mesoplodon eloris, sp. nov. (PL XVIII. figs. 7 a-7 c, and A, 

 B, C.) { = Mesoplodon Floiueri, Canham, MS.) 



The Eev. H. Canham, whose collection of Eed-Crag fossils is now 

 l)reserved in the Ipswich Museum, gave the name of Mesoplodon 

 Floiueri to a new form of Ziphioid rostrum which he had obtained 

 from the Eed Crag of Trimley, SufiPolk. A cast of the specimen is 

 in the Museum of the Eoyal College of Surgeons, and the name 

 given by Mr. Canham is there retained for it (Flower, Cat. Yert. 

 Mus. E. Coll. Surg., part ii. p. 562, no. 2915, 1884). This species 

 is also noticed by Mr. Lydekker (Quart. Journ. Geol. Soc. vol. xliii. 

 p. 15, 1887), but no description has hitherto been published. 

 Unfortunately the specific name Floiveri has already been used by 

 Julius von Haast t for a recent species of Mesoplodon ; but as the 

 form thus designated has been shown by Prof. Flower to belong to 

 a species previousl}^ described, it seemed to me very desirable to 

 keep the name M. Floiueri for this fossil Ziphioid. Since, however, 

 the present paper was read, tJie Eeferee has pointed out that it will 

 be far better at once to establish a new specific term ; and, as by 

 the use of Latin instead of English, the same honoured name may 

 be kept in association with this Cetacean fossil, I propose to call 

 the species Mesoplodon floris [July 1, 1890]. 



By the kindness of Dr. Taylor of Ipswich, I have had the oppor- 

 tunity of examining the original specimen (fig. 7), and propose now 

 to give some details of its structure. In general appearance this 

 rostrum is slender and regularly tapering, something like M. tenui- 

 rostris or M. medilineatus, but exhibiting important diff'erences, 

 its most striking peculiarity being the flattening of the anterior 

 part of the upper surface, which gives to the transverse section of 

 this region a quadrate appearance. The length of this specimen is 

 about 420 mm. (16| inches). The ossified mesethmoid (fig. 7«) 

 occupies about 285 mm. of the upper surface, and is about 23 mm. 

 wide towards its hinder part ; but it becomes narrower towards 

 its front, the anterior third tapering away more rapidly, to end in 

 an acute point. In front of this is a deep median groove which 

 extends to the end of the rostrum. The mesethmoid narrows 

 somewhat posteriorly, and its outer surface seems to consist of 

 denser bone than the interior, probably because it is an ossification 

 of the epichondrium, while the more cancellous interior is an ossi- 

 fication of the mesethmoid cartilage itself. And further, the 

 ossification of the perichondrium is not complete towards the hinder 

 part of the upper surface ; but a median groove is left similar to 



* Brit. Foss. Maram. p. 192 (1846). 

 t Proc. Zool. Soc. 187(), p. 478. 



