1S80.] PUOF. F. J. BELL ON AN IMMATURE ECHINOID. 357 



Society, is the one to which I leferied to in my description of Palao- 

 lainpas crassa} as being under the charge ot" Dr. Traquair, in the 

 Museum of Science and Art at Edinburgh. Dr. Traquair has just 

 arrived in Loudon, and early this morning was good enough to bring 

 me the specimen to the British Museum. 



I have examined it with considerable interest and profit; but I do 

 not find myself able to place it in the new genus Palceo/ampas : it 

 is, I suspect, a comparatively young example of some species of the 

 genus Echinolampas, or, possibly, of Conochjpeus. The following 

 are its more important characters and measurements: — 



Length 33"3 millims., height 17 millims. Test very delicate. 

 The actinal and anal orifices, which have lost all covering-plates, 

 are of proportionally large size ; the former is without bourrelcts, 

 but is provided with well-developed tubercles. When we compare 

 it with Echmolampas, we find that the characters of the actinostome 

 are already as well defined as in E. depressa, and we see, moreover, 

 the probability of the young form undergoing some further modi- 

 fication, such as would in all likelihood bring it, when adult, into 

 very close resemblance to E. oviformis (cf. especially var. orientalis 

 of Gray). So, again, the irregularly cordiform anus is not so large 

 even in this younger state as it is in E. depressa, while its propor- 

 tionally greater size than in an adult E. oviformis is only what we 

 should expect. 



The apical pole is a little anterior to the geometrical centre of the 

 upper surface, and is not at the highest point of the test. 



Coming next to the point which indicates that this creature 

 belongs to a race which is more highly specialized than PalcEo- 

 lampas, we find that its affinities to Echinolampus oviformis are 

 here, again, not obscurely indicated : there is not, indeed, the same 

 diff'erence, as in the adult, between the lengths of the rows of the 

 pores of the same area ; but they all cease to exhibit the regular 

 paired arrangement of the rows of pores at a considerable distance 

 from the ambitus ; the odd anterior ambulacrum ends at 8 millims. 

 above the ambitus ; of the antero-lateral the left is a little longer, 

 and the right is a little shorter than the odd one ; the postero-lateral 

 are, as in the allied forms, a little longer ; and the paired character 

 of the rows of ambulacral pores ceases somewhat more gradually. 

 The pores are rounded ; and there is no slit-like enlargement of one, 

 such as is to be seen in P. crassa or E. depressa. As in E. oviformis, 

 there is a delicate ridge separating every pair of pores from its 

 neighbour ; and we have therefore the pores in grooves. 



If these points are not sufficient to show that the specimen from 

 the Edinburgh collection is more highly diff'erentiated than Palao- 

 lamjjas, I may add two other facts : — 



(1) Save for about a third of the actinal surface, around the 

 actinostome, the ambulacral pores on that surface are exceedingly 

 rare, rarer even than in the adult E. depressa. 



(2) The primary tubercles are more distant than in P. crassa; 

 and though, on the whole, still very regularly arranged, there is a 



1 P.Z.S. 1880, p.43. 



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