18 THE VOYAGE OF H.M.S. CHALLENGER. 



Locality. — Station 307, January 4, 1876 ; lat. 49° 24' 30" S., long. 74° 23' 30" W. ; off 

 the south-west coast of Patagonia ; depth, 140 fathoms ; bottom, blue mud. One specimen. 



Reniera tufa,^ Eidley and Dendy (PL I. figs. 6, 6a ; PL IL fig. 7). 



18S6. Reniera tufa, Eidley and Dendy, Ann. and Mag. Nat. Hist., sor 5, vol. xviii. jx 328. 



Sponge (PL L fig. G) massive, sessile, cake-like ; represented in the collection by 

 two p)ieces, each measuring about 62 mm. long by 43 broad, and up to 20 mm. thick. 

 Colour in spirit greyish-yellow. Texture firm, almost stony, l^ut somewhat brittle, the 

 sponge being traversed by wide canals {vide PL I. fig. 6a). Surface smooth where the 

 dermal membrane is intact, but uneven. Dermal membrane distinct, rather coarse, 

 readily peeling off, strengthened by a close reticulation of spicules. Oscula rather 

 small, circular, with their margins flush with the general surface of the sponge, and 

 each surrounded by a membranous diaphragm which greatly reduces the diameter of the 

 exhalent canals at the surface. Pores, as usual, rounded openings scattered through 

 the dermal membrane. 



Skeleton. — A compact, but rather irregular, almost unispicular reticulation of oxeote 

 spicules, with triangular meshes ; no special dermal skeleton. 



Spicules. — Smooth, very slightly curved, subhastately-pointed oxea (PL IL fig. 7), 

 measuring about 0*2 by O'Ol mm. 



This species seems to come near to Schmidt's Cribrochalina cretacea,^ but differs in 

 the size of the spicules and in the arrangement of the oscula, the latter point being the 

 most remarkable character in Schmidt's species. 



Keller's Reniera litoralis ^ also resembles our species very strikingly, especially in 

 external form ; but here again we find differences in the arrangement of the oscula and 

 the proportions of the spicules. In Reniera litoralis the spicules of the main skeleton 

 are described as being nearly twice the length of those of the dermal skeleton and 

 much more slender, a feature which does not obtain in Reniera tvfa. 



Locality. — Porto Praya, St. lago, Cape Verdes, 100 to 128 fathoms. Two pieces. 



Subfamily 2. Chalinin^. 



1868. CJialinex, Schmidt, Spong. d. Kiiste v. Algier, p. 7. 



1886. Chalinina, Eidley and Dendy, Ann. and Mag. Nat. Hist., ser. 5, vol. xviii. p. 328. 



A considerable amount of spongin is present, typically forming a thick sheath 

 completely enveloping the spicules and uniting them into strong fibres. 



1 So-called from the resemblance to a piece of pumice-stone. 



^ Spong. Atlant. Gebiet., p. 36. ^ Zeitschr. f. wiss. ZooL, Bil. xxx. p. 579. 



