260 SALEXIA. 



the abactinal system of Acrocidaris, and removed the genus to Salenidae on 

 account of the presence of a subanal plate This feature, which seemed so 

 characteristic of a small group of Echini, is one which alone has no primary 

 systematic value, so that we must, I think, hereafter consider the Salenidae 

 simply as a subfamily of Cidaridae, as the description of the species dredged 

 in Florida by Mr. Pourtales will clearly show. 



The mere presence or absence of this so-called subanal plate cannot be of 

 itself sufficient grounds for uniting with the Salenidae such forms as Acrosa- 

 lenia, any more than the presence of four anal plates in Parasalenia removes 

 it from Echinometradae to place it among the Ecbinocidaridae. I am in- 

 clined to doubt, therefore, the propriety of placing Acrosalenia. as limited 

 by Cotteau, among the Salenidae ; and to question the wisdom of removing 

 Goniopygus from it. as it evidently had, like Salenia, the interambulacral 

 granules carrying the second kind of club-shaped spines observed in Salenia, 

 as well as the sutural impressions of the abactinal system which are wanting 

 in true Acrosalenia. Nor do the spines, as far as they are known, warrant 

 such an approximation. The genera of Salenidae have evidently been too 

 much multiplied. The single character of the position of the anus separating 

 Peltastes from Salenia is not. according to analogy, of any generic value; it 

 may be a convenient section of Salenia, but even that is doubtful, to judge 

 merely from the position of the anus, which may be very considerably to one 

 side or the other, as in young Echini ; this seems to support the view taken by 

 Forbes, of the identity of Salenia, Peltastes, and, as Cotteau has shown, also of 

 the identity of Salenia and Ilvposalenia. "When we know something more than 

 we now do of the spines of Salenidae. the identity of these genera may be 

 proved more conclusively. The spines of Goniopygus thus far discovered show 

 an analogy to those of our Salenia ; they evidently had small curved spines, but 

 the larger spines were more or less club-shaped anil ribbed at the extremity. 



Having adopted the view taken by Forbes of the affinity of these genera, 

 borne out by the shifting position of the anus in the anal system of Echini- 

 dae, I have no grounds left for separating, as 1 formerly did. this species as 

 an independent genus from Salenia. with which I therefore now unite it. From 

 what has been said I can see no reason for finding in Salenidae something 

 analogous to the exclusion of the anal system from the abactinal system in the 

 irregular Echini; on the contrary. I am led to consider the conditions there 

 prevalent as eminently embryonic, and to retain, very nearly as it had been 

 done by Agassiz. the limitation of the family and its position as intermediate 



