﻿52 Sir Philip Grey-Egerton — On some Neiv Pycnodonts. 



2. Cgelodus gykodoides, Egerton. Plate IV. Fig. 3. 

 The Earl of Enniskillen possesses a fine specimen of a Pycnoclont 

 vomer from the Greensand of Pinney Bay, near Lyme Eegis, 

 which, although named Gyrodus new species, I am inclined to refer to 

 the genus Ccelodus. It measures two inches and a half in length 

 by one inch and seven-tenths at the base and one inch four-tenths in 

 front. It carries five rows of tritoral teeth. The central series 

 (PI. IV. Fig. 3 a) is composed of eight i-eniform teeth, six-tenths of an 

 inch long by two-tenths wide. They have an elongated sulcus on 

 the anterior face of each tooth similar to those which characterize 

 the mandibular teeth of Coelodus. The adjoining rows on either side 

 have nine teeth on the right side (Fig. 3 b) and eight on the left 

 (Fig. 3 c). They are considerably smaller than those of the centre 

 row and more obtuse. The depression on the grinding surface is 

 larger in proportion to the area of the tooth, and each pit has a 

 slight papilla at the bottom of the cavity. The two outer rows 

 (Fig. 3d d) contain seven teeth in the right and six in the left. 

 These are smaller than those in the adjacent rows and more oval in 

 shape, with a slight truncation of the outer margin. These teeth 

 might be mistaken for those of Gyrodus, but on comparing them 

 with perfect specimens of that genus it will be seen that the 

 periphery of the tooth in it is lower than the central boss, and 

 the crenulation of the projecting ridges more distinct, giving a 

 rosette character to the crown, whereas in Coelodus the marginal 

 teeth have more the appearance of pustules with a puckered de- 

 pression in the centre. There can be no hesitation in affirming that 

 this specimen indicates a new species of Pycnodont. The only doubt 

 is whether or not it can be a vomer of Ccelodus ellipticus described 

 above. I am inclined to negative this supposition, for the following 

 reasons. On applying the vomer to the mandible in the natural 

 position, the former appears to be too small for the latter, both 

 being evidently adult individuals, and the two are unsuited to bring 

 the upper and lower teeth in contact. In those species of Pycnodonts 

 where the dentition of both jaws is ascertained, there is a general 

 correspondence in the forms and character of the principal teeth ; 

 this is not the case here, as the whole dentition differs from that of 

 Ccelodus ellipticus in a remarkable degree, and is unlike that of any 

 Pycnodont hitherto described, I have not been able to ascertain the 

 exact horizon of tlie bed in which it was found ; the only informa- 

 tion I have is that it was derived from the Greensand of Pinney 

 Bay. I propose to call it Ccelodus gyrodoides. 



3. Pycnodus Boweebanki, Egerton. Plate III. Fig. 2. 

 The specific characters of Pycnodus ioliapicus given by Agassiz in 

 the "Poissons Fossiles," vol. ii. pt. 2, p. 196, were taken from a 

 single specimen in the collection of Dr. Buckland ; for although he 

 alludes to a second example in the museum of Dr. Bowerbank, he 

 does not describe it. Some years before Dr. Bowerbank removed 

 from London, I had an opportunity of examining his fine collection 

 of Sheppey fishes, in Highbury Grove, and with his permission made 



