Mr. A. S. Woodward — PaJanchthyohcjical Notes. 2S3 



from Diplodus in the Keuper of Somersetshire [D. Moorei, 

 A. S. Woodw.*). It is now of much interest to be able to 

 add possible evidence of the survival of another ancient type 

 in the form of true Cladodont teeth from Warwickshire. 



All the known examples of these teeth are very small, a 

 series of four being shown of twice the natural size in PL X. 

 fig. 2. The crown (fig. 4) consists of three robust conical 

 cusps, vertically striated except towards the apex, and about 

 equal in width at the base ; the median cusp is nearly vertical 

 and slightly shorter than the outer pair, which incline a little 

 outwards and are almost symmetrical. The root, as shown 

 from above (fig. 3), is horizontally expanded, straight at its 

 outer border, where the coronal cusps arise, bounded by a serai- 

 circular border within. When the teeth are in series (fig. 2) 

 the expanded roots overlap, as in Diplodus^ the Cladodonts, 

 and the modern Chlamrjdoselache^ there being evidently 

 several teeth in function simultaneously in each transverse 

 row. There appears to be no smooth articular facette on the 

 root. 



As in the case of the Diplodont teeth, the new specimens 

 are of course insufficient to prove the survival of an ancient 

 Palaeozoic genus of sharks in the Trias ; they merely suggest 

 that some of the Cladodonts were still to be met wuth in early 

 Mesozoic seas. The form of the teeth, however, differs in no 

 essential respect from the Middle Devonian and Lower 

 Carboniferous type named Phoehodus in America f, the most 

 important differences apparently being the complete suppres- 

 sion of intermediate denticles and the absence of an articular 

 facette on the root in the Triassic specimens. It is therefore 

 proposed to assign to the teeth now described the provisional 

 name of Flioibodus Brodiei. 



Form, and Loc. Upper Keuper, Slirewley, Warwickshire. 



A Byhodont Fin-spine. (PI. X. figs. 5, 5 c.) 



It has already been pointed out that the Triassic Hybodont 

 fin-spines described by Agassiz under the name of Leiacanthus 

 are ])rovided with small ])Osterior denticles. No good figure 

 of an unabraded specimen has, however, iiitherto been ])ub- 

 lished, and a drawing of the finest example of the so-called 

 Hyhodus keuperinus in Mr, Brodie's collection is therefore 

 appended (fig. 5). This spine, like those from the Muschel- 

 kalk, is much laterally compressed, with a sharp anterior 

 border ; the lateral ribbings are fine and numerous, and the 



* Ann. & Mag. Nat. Hist. [(;] vol. iii. p. 2'.>I», j.l. xiv. ligs. 4, -> (l?-8'.J). 

 t St. .John and Wnrthen, I'ateont. Illinois, vol. vi. ]). 2")1 (lH7r)). 



