REPORT ON THE MONAXONIDA. 107 



Desmacidon (f) ramosa, Ridley and Dendy (PI. XXIII. figs. 4, 4fl, 46, Ac ; 

 PI. XXIV. fig. 4 ; PI. XLVII. fig. 6). 



1886. Desmacidon {?) ramosa, Ridley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. 



p. 346. 



Sponge (PI. XXIV. fig. 4) consisting of numerous, irregular, long, vermiform, anas- 

 tomosing branches, about 6 mm. in diameter. One piece in the collection is about 

 212 mm. long, but there seems no reason why it should not grow to a much greater 

 length. Texture tough and leathery. Colour in spirit pale greyish-yellow. Surface 

 uneven and minutely hispid, often with a reticulate appearance. There is a distinct, 

 tough, outer rind, which, however, adheres rather firmly to the underlying tissues. 

 Dermal memhrane very distinct, transparent. Oscula scattered up and down the branches 

 at irregular intervals ; their margins are produced into conical protuberances about 

 2 mm. long. On some branches the oscula are numerous, while in other parts they 

 appear to be almost or entirely wanting. Pores scattered between the radiating 

 brushes of spicules which support the dermal membrane. 



Skeleton. — Of a distinctly radiate type. There is a more or less definite axis of 

 spiculo-fibre running through each branch, from which radiate, though in no very 

 definite manner, numerous bands of spiculo-fibre ; these run towards the surface of the 

 sponge, and on approaching it, break up into divergent tufts of spicules which support 

 the dermal membrane and sometimes project beyond it, causing the hispidity of the 

 surface (PI. XLVII. fig. 6). There is no dermal reticulation, 



Spictdes. — (a) Megasclera ; of one kind only, viz., sharp-pointed, fusiform oxea 

 (PI. XXIII. figs. 4, 4«), measuring about 0'6 by 0"022 mm. (h) Microsclera ; of one 

 kind only, viz., tridentate isochelse (PI. XXIII. figs. 4&, 4c), the shafts of which appear to 

 be extended into slight lateral fimbriae. Length about 0*02 mm. 



It will be seen from the above that in spiculation this species would be reaUy a typical 

 Desmacidon, were it not for the absence of the sigmata. These, however, appear from 

 the study of other genera to be such very variable elements in the s2:)iculation that they 

 cannot be considered as of generic importance. More important, indeed, is the radial 

 arrangement of the skeleton, very difi'erent from that of other species of the genus and, 

 indeed, of most of the family, and making a near approach to the arrangement of the 

 skeleton in the genus Rasi>ailia. 



Loccdities. — Station 142, December 18, 1873, lat. 35° 4' S., long. 18° 37' E.; south 

 of the Cape of Good Hope; depth, 150 fathoms; bottom, green sand; bottom 

 temperature, 47°"0. Several specimens. 



Off Marion Island, 50 to 75 fathoms. One specimen, of much darker (greyish) 

 colour than the previous ones. 



