208 A. Smith Woodward — Greensand Ganoid Fishes. 



2. Athrodon Jessoni, sp. no v., PI. VIII, Figs. 1, la. 

 Type. Eight splenial : British Museum (Jesson Collection). 



Splenial bone very robust, but narrower than in A. crassus, with 

 large, closely-arranged smooth teeth, mostly circular, disposed in 

 three nearly regular longitudinal series. Anteriorly the three series 

 are about equal in size ; posteriorly the median teeth are slightly 

 the larger. 



The dentition on the type, and only known specimen, measures 

 0'02 m. in maximum width and 0-04: m. in length. The seven teeth 

 of the innermost series are well preserved, except the foremost, and 

 the hinder four are very slightly longer than broad. There is a 

 small supplementary tooth within anteriorly. Of the median series, 

 three round teeth remain in front, and then only one at the hinder 

 end, this being slightly broader than long. The three middle teeth 

 of the outer series are preserved, and behind these are the bases of 

 two others ; they are nearly equal in size to the teeth of the inner 

 series, but not antero-posteriorly elongated. 



Genus Ccelodtjs, Heckel. 



Cododus is also represented by two specific types of splenial 

 dentition; and two forms of vomer in the Woodwardian Museum 

 may perhaps be placed here.' The first species, already described, 

 seems to be tolerably common ; while the second species is as 

 yet known only by the unique fossil described below. 



1. Ccelodus incequidens, A. S. Woodward, Geol. Mag. Dec. Ill, 

 Vol. X (1893), p. 491, PL XVII, Fig. 5. 



Type. Left splenial: British Museum (No. 36157). 



2. Ccelodus cantabrigiensis, sp. nov. PI. VIII, Figs. 2, 2a. 

 Type. Eight splenial : British Museum (Jesson Collection). 



A large species known only by the splenial dentition. Teeth on 

 the splenial bone smooth ; those of the principal series scarcely 

 more than twice as broad as long, and nearly equal in width to 

 the two flanking series; inner flanking, teeth twice as broad as 

 long, and twice as broad as the teeth of the outer series, which 

 are scarcely broader than long ; a row within the principal series 

 represented by few small teeth. 



Though relatively gigantic, this ffe"!™ of dentition is almost 

 identical with that of the Wealden Ccelodus Mantelli. Even the 

 almost unworn teeth in the Cambridge Greensand fossil, however, 

 are destitute of any trace of the deep apical indent characteristic 

 of all the Wealden teeth ; there need thus be little hesitation in 

 regarding the present form as specifically distinct. The fi'ont 

 teeth of the type specimen figured are deeply excavated by wear 

 during the life of the animal ; and the inner supplementary teeth 

 are indicated only in front by two bases. 



1 A. S. Woodward, loc. cit. 1893, p. 492, PL XVII, Figs. 3, 4. 



