EXPLANATION OF THE PLATES. 681 



Fig. C. Frontal region of Oonodactylus (Q elegans, J?). Bhowing 

 the form of the rostrum, x'-i. 



D. Part of right gnathopod of Mcera diversirmnus. d, part of 



left gnathopod. 



SPONGES. 



Plate LIII. 



Fig. A. Leucojihheas fenestrates. Specimen which has incorporated 

 many calcareous fragments with its base, and gives off a 

 remarkable smooth flat lobate process (a) from the base. 

 In spirit. From Providence Reef, 24 fms. X 1|. 



B. L. proteus. Variety distinguished by its almost entirely 



massive and smooth habit, a small part only (b) of the 

 surface exhibiting the usual ridged and pilose character. 

 b', apparently accidental pit. In spirit. From Providence 

 Reef, 24 fms. Nat. size. 



C. Dysidea gumminea. Small specimen, based on a stone, 



showing lateral extension into lobes. In spirit. From 

 Providence Island, 19 fms. Nat. size. 



D. Hippospowjia intestinalis, var. Part of a largo contorted 



mass, showing great irregularity of growth and variation 

 in the stoutness of the twisted lobes [the dermal sheet of 

 fibres has been abraded from the lobes towards the top of 

 the figure (<#)]. Dry. From Providence Island. Nat. 

 size. 



E. Axinella proliferans. Left>hand half of small specimen 



from Providence Island, 19 fms. In spirit, x4- F'. 

 Profile view of upper part of same specimen, slightly 

 shaded. Nat. size. 



F. Desmacidon rimosa. The type specimen, showing the large 



vents and well-marked grooves (/',/') of the excretory 



canal-system. In spirit. From Mozambique. Nat. 



size. 



3a 



