ooO THE VOYAGE OF H.M.S. CHALLENGER. 



tuberculate discohcxacts, numerous discoliexasters, in which each of the short simple 

 principal rays bears four long terminals. These become gradually thicker towards 

 the exterior, and finally end in a small compact transverse disc. The size of these 

 discoliexasters varies from 0"05 to 0"1 mm. in diameter. 



The dermal membrane contains pentacts with rudiments of a sixtli distal ray. The 

 four tangentials end in a rough terminal knob, while the longer proximal radial is 

 usually pointed (PI. XCIX. figs. 3, 4). 



Gray's original specimen is said to have been brought from Malacca (?). 0. Schmidt 

 obtained his forms from St. Lucia, West Indies, from a depth of 116 fathoms, and 

 from lat. 23° 1' N., long. 83° 14' W., from a depth of 190 fathoms. 



3. Dactylocalyx{?) f>atella, n. sp. {PL C). 



The completely macerated dictyonal framework displayed in PI. C. fig. 1, probably 

 belongs to a cup- or platter-shaped sponge, with walls at least a finger's-breadth in thick- 

 ness. The tissue consists of an anastomosing network of tubes of very different calibre, 

 varying from 2 to 4 mm. in width, and running in a generally radial or slightly curved 

 course. As to the structure of the natural bounding surface nothing certain cau 

 be said. 



The beams of the dictyonal framework, which form a network with approximately 

 square or more irregular meshes, are moderately strong and quite smooth. Only the 

 conical bosses jn-ojecting radially into the lumen of the canals or beyond its free bounding 

 surface are beset with small pointed tubercles. 



Since no loose spicules were found, it must remain somewhat doubtful whether the 

 generic designation is correct. 



Some specimens of this species were obtained by the Challenger Expedition off the 

 coast of Portugal, others to the south-west of Bermudas, from a depth of 1075 fathoms, 

 and coral mud ground. 



Genus 2. Sclerojjlegma, 0. Schmidt (PI. CI. figs. 1, 2). 



From the diagnosis which the author of this genus has given in his Spougien des 

 Meerbusens von Mexico, p. 56, it unquestionably follows that the genus should be 

 ranked in the family Maeandrospongidte, Zittel. It seems to me doubtful, however, 

 whether all the forms referred by 0. Schmidt to this genus were really ScJeroiolegmata. 

 On the contrary, from his own description, I am forced to conclude that his Sclcrojilegma 

 lanterna and Scleroplegma herculeum belong to another set of forms. But with this I 

 have not much to do, since I have not been able to examine the original specimens of these 

 two species. I have, however, a half specimen of Scleroplegma conicum, Schmidt, which 



