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



ocular plates. They are separated by slight spaces, in which 

 are short pedicellariai ; and they hide tlie generative and ocular 

 pores. As water soaks in easily when placed on the plates, 

 there is no doubt that the pores are there ; but the madreporic 

 plate has no evidence of its peculiar body. The madreporic 

 plate is slightly longer in the antero-posterior direction than 

 the others ; it has a group of close and rather tall, rounded 

 processes of the test in the middle ; and its free edge is slightly 

 convex, and is rendered irregular by the outward projection 

 of some similar growths. It is pentagonal, and the outer 

 edge is shorter than that connected with the generative plate 

 behind and the subanal plate. Next in size is the left anterior 

 generative plate : it is irregularly covered with the peculiar 

 processes ; and pedicellari^ are between them. The generative 

 plate behind this one is narrower and longer, and is covered 

 with the same kind of ornamentation and pedicellariffi. The 

 posterior plate of all is very narrow ; for the anus infringes 

 much upon it. The remaining generative plate is irregular in 

 shape, generally narrow ; and, like that last mentioned, is 

 covered with the peculiar processes and pedicellaria?. 



The two plates last mentioned are the smallest, and they 

 contribute to the formation of the anal opening. 



The subanal plate, in front and to the left of the anus, is irre- 

 gularly geometrical in outline, is aslant, curved, and orna- 

 mented like the others. It is smaller than the madreporic 

 plate. 



There is no projection of the outer edges of the generative 

 plates upon the test beyond the line of the ocular plates ; and 

 they are ragged from ornamentation. 



The sutures are marked by distinct ])urple pigmentation ; 

 they are slight furrows ; but no lateral slits or pores are 

 noticed. 



The ocular plates differ in size. The front one and the 

 right in front are the largest ; all are very irregular in their 

 shape on account of the ridges and processes upon them (fig. 3) . 

 In some there is a prominent outer angle, and then the free edge 

 is nearly straight and nodular, and the right posterior is very 

 close to the anal margin. The smallest ocular plates are the 

 posterior. The pcdicellaria3 are well seen in some. 



The anus is large (fig. 2), nearly circular, and but slightly 

 elliptical; it is eccentric in the right posterior direction; and its 

 raised margin is nearly complete. It infringes on the subanal, 

 the posterior, and the right posterior generative plates, and is 

 behind and to the right of the centre of the a|)ical system. 

 Thesubanal plate, irregularly {)entagonal, limits al^outonethlrd 

 of the anus ; and tiie suture belween the posterior plate and the 



