Prof. P. M. Duncan on the Salenidte. 253 



which extends on all sides but one around the anal opening. 

 The bulk of the subanal plate is close to and on the side of 

 the madreporic plate ; and the almost circular anal opening- 

 is eccentric and its position, as A. Agassiz remarks, as in 

 the test of Hyposalenia (" The abactinal system has the 

 structure of Salenia ; but the position of the anal system is that 

 of Hyposalenia,^^ op. cit. p. 261). Hyposalenia = Peltastes. 



Taking the drawing of A. Agassiz's for:n (plate iii. iigs. 8, 

 11, Revis. Echini) and placing the ocular plate to the left of 

 the madreporic body directly in front, a line drawn through 

 this plate will enter the suture between the madreporic and 

 left front genital plates, and will infringe on the subanal 

 j)late ; carrying it on, the line will cross the anus leaving the 

 bulk of it to the left, and will then cross the posterior genital 

 plate. The anus is very nearly central as regards the antero- 

 posterior axis, and only slightly to the left ; but it is behind 

 the anterior half of the apical disk. In this position the two 

 anterior genital plates are the largest, and the two posterior 

 ocular plates are the largest. The subanal plate is of gi-eat 

 size, and occludes the right posterior plate as well as the left 

 posterior. The anus is marked with ornamentation, and the 

 plates appear to radiate ; only the posterior plate and the 

 subanal limit the anus. The disk is pentagonal and large ; 

 and were it that of a fossil form the species would be placed 

 in the genus Peltastes ; its difl'erences from that of Salenia 

 prof audi are very evident. 



Lovdn thus describes the apical system of his Salenia Goe- 

 siana : — " The apical system is very large, occupying the 

 greater part of the upper surface ; the subanal plate is pen- 

 tagonal ; and the generative plates are very large, hexagonal, 

 with a slightly pronounced seventh angle, corresponding with 

 the reentering angles of the last interradial (interambulacral) 

 plates. The madreporic plate is larger than the others ; and 

 the anal orifice is formed by almost equal portions at the 

 expense of the subanal plate and of the posterior and right 

 posterior generative plates. It is oval and has a raised 

 margin. The ocular plates are pentagonal, remote from the 

 anus, and their pore is close to the external edge. All the 

 surface of the apical system is crowded with a great number of 

 tolerably long sessile prominences, which are cylindrical, with 

 a rounded, swollen, reticulate punctate and lobed summit ; 

 they are close on the periproct, which is furnished with them. 

 The diameter of the individual is 3"5 raillims.; and the madre- 

 poric body is visible from within, but not the generative 

 pores." 



Lovdn's exquisite drawings show the raised anal margin 



