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



is only necessary here to give some further account of the different spicular forms present. 

 Vosmaer (loc. cit.), following Bowerbaiik, sums up the spiculation as follows : — " Spic. tr. 

 ac. ; tr"^. ; A ; CO (large ones and minute ones) ; rut. rut. (' congregated in groups,' 

 large and strong); rut. rut. ('minute'); anc. anc. ('minute'); anc ^2. ('large and 

 stout')." By careful comparison of Bowerbank's own preparations with those from the 

 Challenger specimen, we have satisfied ourselves as to the identity of the two. There 

 can be no doubt that Bowerbank has mentioned as proper to the sponge certain forms of 

 spicules which are really foreign, and he has also omitted to mention the trichodragmata, 

 which are present in his preparations. These facts are pointed out in the "Alert" 

 Report (loc. cit.) by Ridley, who gives the following as the true spiculation : — 



"1. Smooth, sirbspinulate acuate, with slight elongate head; basal end slenderer 



than middle of shaft : "33 by -013 millim. 

 " 2. Large inequianch orate ; large end comparatively short, its tubercle long and 



narrow : "057 millim. long. 

 " 3. Navicular equianchorate : "013 millim. long. 

 " 4. Bihamate, smooth, contort : "095 by '008 millim. 

 "5. Trichite spicules in bunches of two to four or five: '032 to '16 by 



•0018 millim." 



Zom7%.— Station 208, January 17, 1875; lat. 11° 37' N., long. 123° 31' E.; depth, 

 18 fathoms; bottom, blue mud. One specimen, encrusting a Pecten shell. 



Habitat. — Straits of Malacca (Bowerliank) ; Port Darwin, Australia (Ridley) ; 

 Philippine Islands (Challenger). Shallow water. 



Esperella gelatinosa, Ridley, sp. (PL XVI. fig. 7). 



1884. Esperta gelatinosa, Eidley, ZooL Coll. H.M.S. "Alert," p. 611, pi. liv. figs./-/'". 



This species, which was obtained abundantly by the "Alert" expedition at Providence 

 Reef and Providence Island, Mascarene group, is represented in the Challenger collection 

 by one fine specimen from Cape York, Torres Strait. The Challenger specimen (PI. XVI. 

 fig. 7) is much larger than any previously obtained, and is divided into three lobes, the 

 largest of which has a height of 45 mm. by a maximum breadth of 22 mm. As 

 the species has already been fully described {loc. cit.), further details would be 

 superfluous. 



Locality. — Cape York, Torres Strait, 8 to 11 fathoms. One fine specimen. 



Habitat. — Mascarene Islands (Ridley) ; Torres Strait (Challenger). Shallow 

 water. 



