88 CEYLON PEARL OYSTER REPORT. 



only a part of the total number was forwarded to me for investigation, under the 

 impression that they were all specifically identical. I am therefore unable to say how 

 many of each were really collected by Professor HERDMAN and his assistants. Even 

 small specimens are, however, very easily distinguished by microscopical examination, 

 as will be evident from the above descriptions, and the species are not really even 

 closely related. 



Mr. CARTER received his material of this species from the Gulf of Manaar. 



R.N. 120, 122, 123 (deep water off Galle, up to 100 fathoms). 



Geodia ramodigitata, CARTER. 



1880, Geodia ramodigitata, CARTER (4) ; 1888, Geodia (?) ramodigitata, SOI.LAS (15). 



There is one specimen in the collection which appears to be referable to this species. 

 It is of remarkably irregular shape, with one strongly curved, finger-like projection or 

 branch. Unfortunately the specimen is a good deal injured on one side, so that the 

 exact shape cannot be determined. The maximum diameter of the specimen in its 

 present condition is about 40 millims. The colour (in spirit) is pale grey, and a good 

 many foreign bodies are attached to the surface here and there. The vents are 

 minute, for the most part irregularly grouped over the ends of large exhalant canals, 

 with which they communicate by means of narrow chones penetrating the cortex. 

 The outer ends of these chones are usually covered over by a sieve-like dermal 

 membrane which sub-divides the vent into a group of comparatively small pores. 

 Inhalant pores irregularly scattered, perhaps sometimes in groups, but of the numerous 

 pore-sieves present in the dermal membrane it is extremely difficult to say which are 

 inhalant and which exhalant. 



The layer of sterrasters is about 1 millim. thick and lies close up to the dermal 

 membrane, with the cladi of the trisenes spreading out beneath it. The dermal 

 membrane is very minutely hispid with projecting oxea. 



The spiculation is as follows: (1.) Orthotrieenes ; shaft stout, gradually and 

 finely pointed, about 2*5 millims. by 0'08 millim; cladi stout, sharp pointed, up to 

 about 0'35 millim. long, extended nearly at right angles to the shaft. Sometimes 

 one or more of the cladi undergoes reduction or may even become obsolete, leaving the 

 spieule with two, one or no properly developed cladi, as the case may be. 



(2.) ProtriaBnes ; shaft very long and slender, measured up to about 37 millims. 

 by 0'023 millim., with sharp-pointed cladi about 0'18 millim. long. 



(3.) Anatrisenes ; shaft very long and slender, measured up to 4'0 millims. by 

 0'018 millim.; with stout, recurved, sharp-pointed cladi about 0'09 millim. long; 

 not very numerous. 



(4.) Somal oxea; gradually and sharply-pointed at each end, about 2'57 millims. 

 by 0'04 millim., often slightly curved. 



(5.) Cortical oxea; about 0'2 millim. by 0'007 millim. 



(6.) Sterrasters ; about 0'09 millim. by 0'075 millim. 



