A. Smith Woodward— Fish Fauna of Piirbeck Beds. 151 



some detached jaws of considerable interest, and two forms seem 

 worthy of immediate notice. 



Caturus tenuidens, sp. nov. Plate VII. Figs. 7, 8. 

 This form of jaw, not uncommonly met with in the Purbeck Beds of 

 bwanage, requires a provisional name, and two typical specimens are 

 shown of the natural size in PI. VII. Figs. 7, 8. Fig. 7 represents the 

 greater part of a right mandibular ramus, which may be regarded as 

 the type of the species, and Fig. 8 shows a left maxilla, both fi-om the 

 outer aspect. Another left mandibular ramus in the British Museum 

 (^ 0. P 442) IS also typical. The dentary bone is almost smooth 

 externally, only displaying some rugosity towards its inferior border, 

 and its hinder margin is excavated for union with the angular element. 

 Posteriorly it suddenly rises into the coronoid process, which is bent 

 somewhat inwards; anteriorly it tapers to an acute point, curved 

 a little upwards. The teeth are very slender, often slightly bent at 

 the apex, and not expanding at the base; they are comparatively 

 uniform m size, not crowded, and the height of those in the middle 

 of the series is considerably less than the depth of the bone at their 

 insertion. The maxilla is very narrow, but robust, and with a slight 

 siginoidal curve ; its teeth, which are similar to those of the dentary, 

 are largest m front, and gradually decrease in size backwards. 



The jaws thus described are indistinguishable from those of the 

 genus Caturus, to which it is almost certain they will eventually prove 

 to pertain. Among described species they appear to approach most 

 closely the corresponding parts of Caturus furcatus and C. pachyurus 

 of the Bavarian Lithographic Stone ; but in both these species the 

 teeth are more expanded at the base, and those of the middle of the 

 dentary seem to be at least as deep as the bone at theii- point of 

 insertion. It is also most improbable that the fossils now under 

 consideration represent the young of Caturus {Strobilodus) Purleehensis, 

 which has jaws and teeth of very different proportions. They may 

 therefore receive the provisional name of Caturus tenuidens. 



CEonoscopus, sp. Plate VII. Fig. 9, 



. ^/\^^t"^-^^^^^^^ ^^ *^^ British Museum, shown of the natural size 

 in PL yil. Fig. 9, seems to indicate a geniis of fishes not hitherto 

 recorded from British strata. It is not sufficient for specific determi- 

 nation, but a brief account of its characters may lead to the discovery 

 of other remains of the same fish. The bone is much laterally 

 compressed, and considerably more than twice as deep behind as in 

 front; its hinder margin is slightly excavated; while a large and 

 robust antenorly-dii-ected process for the palatine articulation cmwes 

 slightly inwards from its anterior end. Its outer face is almost 

 smooth, being very faintly rugose, and the oral margin is only slightly 

 sinuous. The teeth do not vary much in size, and are small, but 

 stout and conical, with the blunt enamelled apex turned somewhat 

 inwards They are hollow and smooth, and closely, though irregularly, 

 arranged. Some teeth are broken away from the gaps observed in the 

 series. 



This fossil resembles the maxilla of Meqalurus, though very much 

 larger than the bone in any known species of that genus ; and on 

 instituting comparisons, it will be found to agree stillmore' closely 



