BIHANG TII>L K. SV. VET.-AKAl). IIANDI-. I5AN1) 1. N:0 9. O 



and 1. cntlickiodon in whicli it is greatcr tlian in any other 

 Britisli specimen. Microscopic sections give but little insiglit 

 into the finer structure, the tissues are too slaattercd and tra- 

 versed by calcite. The pulp cavity is very large, it con- 

 tracts near tlie end of the toothroot, and here it becomes 

 plugged by a mäss of vascular osteo-dentine continuous exter- 

 nally through the open cavity with tlie external cementum 

 which composes a large proportion of the tooth-root. In 

 these particulars, although not in the shape of the crowns of 

 the teeth, so far as this is known, thcre are Ichthyosanrian 

 resemblances. 



On the whole the present cvidence before me inclinas 

 me to regard it as part of the skull of an individual of this 

 genus, but this determination must be regarded only as provi- 

 sional iintil confirmed or corrected hy new and better material. 



Impression of a larger jaw. 



An elongated triangulär impression in a piece of black 

 limestone (labclled Is fj. Saurie Hk. 1864) represents a jaw 

 armed with strong cylindro-conical teeth. Ten of these occupy 

 a space of 2,3 inches. The only one which has a complete 

 apex measures 0,5 inch long. The pulp cavity, represented 

 in five by a stont cone of calcite exposed by the perfect 

 disappearance of the dentinal tissue, is large, open at the basc 

 where the pulp appears to have spread out and rested on the 

 surface of the subjacent bone possibly having been in some 

 of the teeth confluent with it. The extreme tooth nearest the 

 wider end of the fossil has a less expanded pulp-base than 

 the others, it is also higher, and it has a small basal, late- 

 ral hollow evidently once occupied by a germ. The teeth 

 decrease in size from the narrow to the wider end of the 

 fossil. There are indications that this jaw had a composite 

 structure, but the evidence does not enable me to say whether 

 it belonged to a reptile or a fish. Its determination must be 

 left till better material is obtained. 



Cylindroid fragment of a slender mandible. 



Two pieces of shale labclled (118) (121) contain each a 

 piece of a tapering cylindroid bone which united have a length 



9 



