320 PROCKEDINGS OF THE ACADEMY OF [1890;. 



granulation over the surface of tlie body. The branches of the 

 rosettes also, in this species, very rarely coalesce to form plates, and 

 the wart-like prominences sparsely scattered over the dorsal surface 

 are also a distinguishing feature. True papillie are confined to 

 the summits of these prominences, and the remainder of the dorsal 

 surface is evenly covered with pedicels only slightly smaller than 

 those of the ventral surface. In the superficial appearance of granu- 

 lation it resembles Holothuria grisea of Selenka, but the deposits 

 of this species are collected into circles, and not heaps. It also 

 differs from Holothuria grisea in the fact that the disks of the tables 

 have a hole at the base of each rod and are not provided \vith 

 spines, and that there are two well developed bundles of madreporic 

 canals, instead of a single free canal. 



Holothuria Silamensis, n. sp. PL VIII, ligp. 7-0. 



Body cylindrical, equally rounded at both ends, about three times 

 as long as broad. Anus round, not stellate. Surface smooth to the 

 touch. Dorsal and ventral surfiices possessing pedicels of small 

 size, more numerous upon the ventral than upon the dorsal surface, 

 but not crowded. The ventral pedicels show an imperfect arrange- 

 ment in three rows, of which the middle row is the widest. A 

 few papillse are scattered amongst the dorsal pedicels. 



The pedicels possess a well developed terminal disk. In two out 

 of many pedicels that I examined I found extremely rudimentary 

 tables around the edge of the disks. The tables are apparently of 

 the type which is found in its perfect form in Holothuria atra. 



In the one case there were two present and in the other, one. 

 These must be regarded as exceptional structures as I did not find 

 any trace of tables elsewhere in the specimen. Probably they are 

 rudimentary structures derived from an ancestor possessing tables. 

 The walls of the pedicels are free from deposits. The papillae 

 contain a rudimentary terminal disk and several smooth rib-like 

 rods with perforated ends, such as are characteristic of them. The 

 calcareous deposits of the body-wall are not numerous and consist 

 entirely of small, irregular, perforated plates, which are formed by 

 the coalescence of the branches of rosettes. They usually have one 

 diameter longer than the other; thelongdiameterbeingabout'OSmm, 

 and the short diameter, "02 mm. They occur in small heaps, but the 

 heaps ai'e not suflBciently large or numerous to produce the granu- 

 lated appearance, which is possessed by the previous species. 



