144 



CEYLON PEARL OYSTEE REPOKT. 



Reniera, sp. ? 



A small massive specimen with a couple of short, mammiform, vent-bearing 

 projections. Surface smooth. Colour (in spirit) pale yellow; texture compact and 

 firm, but brittle. 



Main skeleton a compact, irregular, " Isodietyal " reticulation of spicules without 

 any fibres. Dermal skeleton a dense but thin layer of tangentially placed oxea 

 crossing one another in all directions parallel with the surface. 



Spicules. Oxea ; slightly curved, usually gradually sharp-pointed at each end ; 

 occasionally strongylote ; size about 0"164 millim. by 0"008 millim. 



This species may possibly be identical with one of the numerous imperfectly known 

 European species of Reniera (Isodictya). 



Tfc.N. 232 (deep water off Galle and onwards up West Coast of Ceylon). 



Petrosia, Vosmaer. 

 Renierinae usually of hard or even stony texture, owing to the density of the skeleton, 

 which is composed of an irregular reticulation of oxeote or strongylote megascleres 

 (usually short and thick), packed close together, sometimes in stout fibres. 

 Those species of this genus which have a more or less fibrous skeleton make a close 

 approach to the genus Pachychalina, 



Petrosia testudinaria (Lamarck). 



[For literature and synonymy vide Dendy (3).] 



This handsome sponge (see text-figure 1) has been recorded from Queensland (Ridley) 







$?**!%>*. .ifSsSc* 



Fig. 1. Petrosia testudinaria (Lamk.), C4ulf of Manaar; 

 reduced one-half, 



Fig. 2. Pearl-oyster shell honeycombed by 

 cliniiK marguriHfertB Dendy (see p. 128). 



