32 Dentition and Characters 



The teeth are all more or less coloured as in the lust species. 

 The dental formula is as follows : 



Mid. Inc. | ; lat. Inc. | : § ; Mol. f : f ; = {%. 



S. remifer. (Of English Authors.) 

 Of this species I have only been able to examine accurately the 

 dentition of a single specimen. It does not differ materially from 

 that of the S. fodiens last described. The processes on the inner 

 margins of the upper middle incisors are rather more developed, 

 and it is by means of these processes only that the two teeth ap- 

 proach one another. The fourth lateral incisor in the upper jaw is 

 also a trifle larger, and terminates upwards in a more decided point. 

 The lower middle incisors have their upper margins perfectly en- 

 tire, not exhibiting even the rudiment of a single denticle. The 

 colouring of all the teeth is the same, but in the specimen examin- 

 ed, not very intense. 



After the details above given, it is hardly necessary to dwell on 

 the essential differences between the first two of our British species 

 and the two continental ones bearing the same names. It will be 

 readily seen, on referring to the characters of Duvernoy's three 

 types, that they differ particularly in the form of the middle inci- 

 sors in both jaws, and in the number, as well as in the relative size 

 of the lateral incisors above. The difference in number amounts, in 

 the case of the S. araneus, to as many as four. It is in fact not a 

 little singular that the dental svstem of our araneus should be near- 

 ly coincident with that of the continentaiybf/ie?^- ; while that of our 

 fodiens, though not exactly the same (in as much as it clearly be- 

 longs to Duvernoy's third type,) should yet closely approach the den- 

 tition of the continental araneus. But besides the distinctive cha- 

 racters afforded by the teeth, there are others observable in the form 

 of the cranium. Of this I judge from a comparison of Duvernoy's 

 figures of this part with the same part in our British specimens. In 

 the instance of the S. araneus, the cranium is slightly larger in all 

 its dimensions, but especially wider across the snout and less atte- 

 nuated, than in the araneus of this country. In the 5. fodiens, it 

 is decidedly smaller, and the proportions of the snout not so consi- 

 derable. 



But if our British species be not the same as the S. araneus and 

 fodiens of continental authors, it will naturally be asked, — to what 

 other species we are to refer them ? To this inquiry, at least as re- 

 gards one of them, it is not so easy to return a direct answer, until 



