Mr. II. J. Carter on the Lithistidse. 443 



especially upon the growing edge or margins of the specimen. 

 The specimens are covered with dried sarcode, evidencing that 

 they were taken alive and may so far be considered perfect. 

 Hence there is no doubt about their possessing no characteristic 

 surface-spicule ; for I searched for this in many parts. Still I 

 think it just possible that this may be explained by assuming 

 that the surface-spicule had passed into the form of the body- 

 spicule before the new layer of surface-spicules had been 

 developed. 



Be this as it may, the specimens are magnificent and mag- 

 nificently perfect ; not, perhaps, from any particular care 

 having been bestowed on their preservation, but because, 

 contrary to what one would infer from their glassy structure, 

 they are so tough that it is difficult to get a piece off them. 

 One is 14 inches in diameter and 11 inches high, and the 

 other not quite so large. They are flattish, cabbage-like, in- 

 foliated, with branched sinuous laminae - a T to T 3 T inch thick, 

 vertical, widely separated, and proliferous. The vents are a 

 little raised on papillary eminences, and scattered over the 

 inner aspect of the fronds or laminge ; while the pores are out- 

 side, as in MaeAndreivia azorica, to which it bears a strong 

 general resemblance. My reason for stating all these cha- 

 racters is because these specimens have hitherto not been 

 described. 



Corallistes borealis is the name which I have given to de- 

 ciduous fragments of a Lithistid dredged up on board H.M.S. 

 ' Porcupine ' between the Faroe Islands and the north coast of 

 Scotland. They have no characteristic surface-spicule ; and 

 in their body-structure are confusedly mingled both the 

 simple form of surface-spicule characterizing Dactylocalyx 

 Bowerbankii and that of D. polydiscus respectively. Various 

 other sponges have built their structures upon them, among 

 which is that possessing the snake-like form of large acerate 

 spicule figured by Schmidt in connexion with his representa- 

 tion of Corallistes typus {op. cit. pi. iii. fig. 3 c), which of 

 course is also parasitic. How to account for the surface- 

 spicules before mentioned occurring among the body-structure 

 of Corallistes borealis I know not. 



For the structure and form of the remaining Lithistidae and 

 their spicules, I must refer the reader to Schmidt's work on 

 the Atlantic sponge-fauna, already mentioned, where they are 

 respectively described and figured. 



I would, however, for a moment more here revert to the 

 fossil species Lithospongitis Kittonii, which Mr. F. Kitton, of 

 Norwich, found in a flint of the Upper Greensand taken from 

 an artesian well at Carrow, close to Norwich, to observe 



