112 OKHAMANDAL MARINE ZOOLOGY REPORT PART II 



spacious interior. The inner surface of the cup is smooth but uneven ; it bears no vents. 

 The outer surface is similar, but bears numerous large, prominent, circular vents, up 

 to about 9 mm. in diameter, leading out of wide exhalant canals which come from deep 

 down in the interior of the sponge. The texture is fairly firm but rather cavernous and 

 friable ; the colour in spirit (after formalin) pale yellowish-grey, with a transparent 

 look which is probably due largely to the imperfect preservation. 



Another specimen (R.N. XXXIII. 2 a) forms a much flatter crust growing over a 

 massive specimen of Jaspis reptans, and there are also a number of broken fragments 

 evidently of the same species. 



The main skeleton is a typical unispicular, isodictyal reticulation of short oxea, 

 and there is a similar unispicular dermal reticulation, except that here the spicules all 

 lie in one plane, parallel to the surface. Just beneath the surface, however, there is a 

 well developed subdermal reticulation of short, multispicular fibres. This reticulation 

 lies parallel to the surface. Its meshes are very irregular in shape and vary greatly 

 in size, and the component fibres vary very much in thickness, up to at least 0-17 mm. 

 The dermal and subdermal skeleton are similar on the inner and outer surfaces of the 

 sponge. Here and there in the interior of the sponge a reticulation of coarse spicular 

 fibre similar to the subdermal reticulation is to be found, probably representing lines 

 of growth (earlier surface levels). 



There is little, if any, spongin present in the skeleton. 



Spicules. Oxea ; fairly stout, slightly curved, sharply and rather abruptly pointed, 

 but not tornote. Size about 0-16 by 0-0095 mm. 



This handsome species, with its well developed subdermal reticulation of stout 

 multispicular fibre, seems to be intermediate between Reniera and Pachychalina. 



Register Numbers, Localities, &c. XXXIII. 1, 2 a, 3, Dhed Mora and adjacent rocky 

 ground between Beyt and Aramra, 1 fm., 21.12.05 ; XXXIV. 7, 9, Channel, W. side of 

 S. end of Beyt Island, 3-4 fms., 3.1.06. 



Reniera spp. 



There are also in the collection a number of more or less fragmentary specimens 

 probably representing other species of this difficult genus. 



21. Halichondria panicea Johnston vars. 



(For Literature, Synonymy, &c., vide Ridley and Dendy [1887] and Dendy 

 [1905].) 



There are several specimens in the collection which may be considered as varieties 

 of this ubiquitous species. R.N. XX. 3 a is the best preserved and characterised. It 

 consists of a compressed Jobose fragment (? erect), 51 mm. in length and 30 mm. in greatest 

 breadth (near the top, where it expands somewhat). A number of good-sized venjts 

 occur around the margin. The surface, under a pocket lens, appears very distinctly 



