SPONGES. 85 



rays is not figured by BOWERBANK in his illustration, nor mentioned in the text, 

 makes me a little doubtful of the identification of the Ceylon species with that 

 originally described by BOWERBANK (from an unknown locality). CARTER, however, 

 made the identification in the first instance and SOLLAS has accepted it; and the 

 differences, if they really exist, must be extremely slight. 



RN. 119, 121, 124, 125, 126, 135. (All from deep water, up to 100 fathoms, nff 

 Galle and onwards up the West Coast of Ceylon.) 



Geodia peruncinata, n. sp. Plate III., figs. 3, 3A, SB. 



The single specimen in the collection is, unfortunately, only a fragment, amounting 

 to probably somewhat more than half of a small spherical sponge, attached to a 

 small calcareous nodule. The diameter of the specimen is about 1 1 millims. The 

 colour in spirit is nearly white, both on the surface and in the interior. The cortex 

 is rather thin and very brittle, and the interior of the sponge is soft and friable. 

 It is impossible to make out the arrangement of the exhalant canal-system, but the 

 thin dermal membrane contains numerous small pores, presumably inhalant. 



The layer of sterrasters (Plate III., fig. 3, e, e) is about 0'33 millim. thick, and is 

 separated from the dermal membrane by an interval of about 0*165 millim. occupied 

 by extensive sub-dermal cavities. The dermal membrane is supported on the 

 cladomes of dichotriaenes (Plate III., fig. 3, a'}, whose shafts pierce the layer of 

 sterrasters and the zone of sub-dermal cavities ; it is also strengthened and rendered 

 hispid by the presence of immense numbers of short anatrisenes which project from 

 the surface at various angles (Plate III., fig. 3, c, c). Some of the dichotriaenes 

 (Plate III., fig. 3, a) have their cladi extended beneath the layer of sterrasters, and 

 the remainder of the skeleton is arranged in the usual way, with radiate primary 

 lines. 



Spicules. (1.) Dichotrisenes (Plate III., fig. 3, a, a'); with stout shaft tapering 

 gradually to a narrow, but blunt apex, and short cladi ; the deuterocladi usually two 

 or three times as long as the protocladi, but variable and often unequal, gradually and 

 sharply pointed, slightly curved towards one another, or straight. Shaft measuring 

 up to about 2 '4 millims. by 0'044 millim., with cladome 0'62 millim. in total diameter 

 and protocladi 0'038 millim. thick. 



(2.) Protrisenes ; a few stout protrisenes, more or less broken and sometimes with 

 four cladi, occur amongst the mass of spicules projecting from the base of the 

 sponge. 



(3.) Anatrisenes (Plate III., fig. 3, b) ; with well-developed cladome and very long, 

 slender shaft. Shaft measured up to about 4 '9 millims. in length (and then broken 

 off), with a thickness of O'OIG millim. near the cladome, and cladi stout, conical, 

 and about 0'057 millim. long. (Projecting from the base of the sponge one finds 

 anatrisenes with long, hair-like shafts and slender, very sharply recurved cladi.) 



(4.) Anatrueues (Plate III., fig. 3, c; fig. SA) ; with short, slender, fusiform shaft 



