2 



BRITISH FOSSILS. 



Conulus, of which Galerites alhogalerus is the type. Leske, in his 

 edition of Klein (p. 171), reunites the genera, and describes the species 

 in detail. He remarks, however, that the figure of Plott is too doubtful 

 to be quoted as a representation of the Echinites subuculus, and that it 

 seems rather to represent a madrepore. He exercises more critical 

 judgment in the examination of his references than is shown by some 

 of his successors ; who, indeed, whilst quoting him, do not appear to 

 have read his text. He rejects, also, a figure in Langius, whose work 

 I have not been able to see. Since then it has been figured, seldom 

 very well, by Alexander Brogniart, from French specimens, by Goldfuss 

 and Bronn from German examples, and by Parkinson (badly) from 

 English ones. The latest and best representation is that given in the 

 " Monograph of Galerites," by Desor. 



Description. — The body exhibits an outline exactly orbicular, or 

 occasionally exhibiting a very slight tendency to a pentangular contour. 

 It is regularly convex above, but to a greater or less degree in different 

 specimens, exhibiting every gradation of variation, from prominently 

 conical to subdepressed. The upper surface is divided into five broad 

 and five narrow segments, by the avenues of pores, which regularly 

 radiate from the ovarian circle crowning the summit. The under 

 surface is more or less flattened, with more or less rounded margins, 

 and a more or less concave centre, in the middle of which is the 

 circular mouth, and between the mouth and the posterior margin a 

 large oblong anus. 



The interambulacral segments are, in their widest part, rather more 

 than twice the breadth of the ambulacrals. The plates composing their 

 dorsal portion rarely exceed 13 in number in full-grown specimens, of 

 whatsoever shape. The central ones are broader than long ; those near 

 the summit more and more nearly of equal dimensions in both direc- 

 tions : but whatever be their horizontal diameter, their vertical measure 

 is nearly the same in all. Their surfaces are thickly studded with 

 minute secondary granules, more or less regularly arranged, often 

 appearing as if placed in horizontal series. Each plate exhibits a more 

 or less distinct subcentral carination, so that in many specimens the 

 interambulacral spaces appear as if partitioned by two diverging keels, 

 one on each side of the line of junction of the interambulacral plates. 

 In the line of carination each plate bears a prominent primary tubercle, 

 and in an horizontal row with it, towards the interambulacral suture, 

 are two or three others similar in size and shape ; whilst on the other 

 division of the plate, towards the avenue, two or more similar tubercles 

 are also seen, placed in tw o oblique series with reference to the position 

 of the tubercle on the carina. Consequently, on the avenue side of 

 each carina, in the interambulacral spaces, the tubercles appear as if 



