SALENIA VABISPINA. 21 



mens, and in the older ones there seems to be considerable variation in the 

 position of the madreporic body; so that the position of the madreporic 

 genital can certainly not be taken as expressive of anj generic value in this 

 family, if we are to judge by the pecenl species. It is not uncommon (five 

 specimens) to find tun genital plates which carry traces of the madreporic 

 bod and though the right genital is the one which is inosl commonly the 

 madreporic, yel in the first specimen of this specie, of Salenia described it 

 was the left genital plate which carried the madreporic body. This induced 

 Duncan ' to refer this species to Peltastes.t 



The crenulation of the tubercles can be traced in the earliesl stages ex- 

 amined, but its distinctness varies greatly in differed individuals. It is quite 

 distinct in the large primary tubercles near the abactinal region, it becomes 

 indistinct near the ambitus, and at the actinostome the tubercles are smooth. 

 The large primary pedi.ella.ia-. both in the ambulacral and interambulacral 

 areas, are not numerous. We do not find more than two large, short- 

 stemmed, long-headed, slender-pronged pedicellariae in each of these areas. 

 The other., very numerous, are quite small, short-stemmed, stout-headed 

 pedicellate. In the ambulacral system these small trilid pedicellariae are 

 thickly placed throughout the area,; and in specimens measuring 7 or 8 mm. 

 in diameter there are six or seven similar pedicellariae in each of the large 

 buccal plates of the actinostome. 



The plates of the actinostome are more numerous than in S. Pattersom, 

 and an- not as regularly arranged as in that species, in which the acti- 

 nal imbricating plates resemble the actinal plates of the Cidaridae, both in 

 their regular arrangemenl and in forming the continuation of the ambu- 

 lacral ;111 ,1 interambulacral coronal plates on the actinal membrane. In a 

 specimen of A', varispim measuring 7 mm. in diameter, there are four or 

 live concentric rows of actinal plates between the large buccal plates and 



• Ann. and Mag. of Nat. Hist., XX.. 1.77. 



t Tlll _, ^ | ! iu the genua Salenia, although Dr. Duncan has proposed to remove i. to 



Peltastes. A. I havi i : ' >">' °* the Ecuinl < : "" 1 '" ''"' Bulletin " f the Mu " '"" 



(I., N-„.-i), when Bret describing thi imewhal from Salenia proper, nol Beeni 



to me in belong to the group of Salenidas « ith which Peltast. a is n iated, in which the Buranal plate ia 



placed directlj of the genital plat, .while in Ml .1,, , at Salenidsa thu 



they at least all agree in having an oculai plat op] 1 to the median bne of the auranal | 



adjoining genital plates uniting jusl infronl of this in 



plate more or less from em. (Vide \ ion of the Echini ; S.Loven,£eJ 



M. !•. Duncan, Ann.'and Ma,- ol Nat. Hist., 1877, L878; Wyv. Thorn Voyage of the Challenger; 



A. A . 1 ' liallenger.) 



