184 CEYLON PEARL OYSTER REPORT. 



and size, stout and slender mixed up together. At the surface, lying immediately on 

 the main skeleton, there is a thin dermal layer of short and rather slender oxea, 

 through which the apices of the large underlying spicules frequently project. In the 

 processes of both kinds, large and small, the spicules of the main skeleton for the 

 most part run lengthwise, and there is the same irregular dermal reticulation of small 

 oxea. There are none of those characteristic radiating pillars of spicules, supporting 

 the dermal membrane over large sub-dermal cavities, which we find in a typical 

 Ciocalypta,. 



Spicules. (1.) Large and very stout (Plate XII., fig. 1, a-k), typically fusiform 

 oxea, but variously ended, sometimes stylote or strongylote, always more or less 

 curved, sometimes biangulate, sometimes very crooked and irregular ; size about 

 I'l millims. by 0'065 millim., but variable. 



(2.) Short, slender oxea (Plate XII., fig. 1, /); usually biangulate, gradually and 

 sharply pointed at each end, symmetrical; measuring about 0'18 millim. by O'OOS 

 millim., but variable. These forms occur chiefly, but not entirely, in the dermal 

 skeleton ; while between these and the largest spicules numerous intermediate forms 

 (Plate XII., fig. 1, m) may be observed. 



The above account of the spiculation is taken from R.N. 152, but the spiculation of 

 the other specimens does not differ in any important respect. 



The species may be distinguished from its European congener, S. placenta (the type 

 of the genus), by the development of the finger-like outgrowths (which, however, may 

 be not always present) and by details of spiculation, such as the absence of the central 

 inflation of the oxea. 



RN. 68 (Gulf of Manaar); 77 (Stat. XLV., off Pantura, 25 fathoms) ; 134, 202 

 (deep water off Galle and onwards up West Coast); 152; 182 (Stat. XLIIL, off 

 Kaltura, February 19, 1902). 



Spongosorites (?) lamellata, n. sp. Plate XII., fig. 2. 



Sponge irregular, compressed, lamello- digitate ; only 3 millims. or 4 millims. in 

 average thickness, with a maximum length of about 45 millims. ? Erect. Surface 

 granular in appearance and minutely hispid, fairly smooth but uneven ; margins 

 rounded. Colour (in spirit) pale greyish -yellow. 



The main skeleton consists of a dense and very irregular reticulation of styli, mostly 

 scattered singly, but occasionally collected in loose strands. The dermal skeleton is 

 formed of a thin layer of small slender oxea, lying tangentially to the surface and 

 very irregularly scattered. 



Spicules. (1.) Styli (Plate XII., fig. 2, a, b, c) ; usually fairly stout and slightly 

 curved or crooked (especially towards the base), narrowing slightly to the base, which 

 is evenly rounded, and tapering gradually to the apex, which is sharply pointed ; size, 

 when fully grown, about 0'95 millim. by 0'02 millim., but numerous ' smaller and 

 more slender forms occur which are apparently young. 



