Hi:\ \< TINT.I.I.in.V. 



livi.l.- into two or three terminals tipped with toothed discs. 

 (IV. Ig). .'/* in <li imeter, have slender primary rays, each 6'5/x in length, ending in a 

 plano-ec.n\e\ r;i[iitnliim,i frmii the distal convex surface of which are given off disc- 

 tippe.l terminal rays of two lengths. 



Tliis -jHMjies is placed under tfyaioMU on account of the aWnce of calycoconics, 

 this negative character being the chief one which separates the genus from liaifflla. 



The tliP-e other known species of Hyaltiscuf, (5, p. 87), viz., //. *i</u mien fix lj.. // 

 timilis lj., and //. ;/i;/>intfw Ij., are Japanese. They are all vase- or sack-shaped ; the 

 tir-t -named spe,-ie- is vase-shaped, has an orifi< with everted lips, and is much 

 contracted Mow : the second, which Ijima regards as possibly identical with the first, 



h.i- a Ki-.il -talk ; tlic third icathti t' a lar_"' ll.-n |.-nr,| HM itlia pl.iii IK . 



In all the Japanese species the autodermalia are mainly pentactins, but in the 

 Antarctic species these spicules arc mainly hexactins, pentactins being very rare. 



Near the lower end of the sponge is a small conical elevation about 1 3 cm. in 

 height, \\itli a central axis of diactins. The autodermalia have here undergone a 

 remarkable change (IV. Ic-c 1 ) ; they have become more or less fused together, and 

 have lost one or more of their rays, while the spines resemble the flat articular surfaces 

 ami tubercles on the desmas of Lithistid Sponges. All the stages of transition can be 

 traced from a slightly modified pentactin to a long desma-like form, such as that figured 

 in Plate IV'., fig. lc f . Probably these changes have resulted from irritation set up by 

 contact with some foreign Ixxly, just as basidictyonalia form at the point of attachment 

 of many of the Hexactinellida. On another part of the dermal surface is a small round 

 patch, 1 ' 5 cm. in diameter, lighter in colour than the rest of the surface, occupied by 

 small densely crowded autodermalia. Ijima (5, p. 90) refers to similar patches on the 

 gastral surface of //. x<i;i<tiniensi8, " due to excessive local accumulations of gastralia." 



Dredged from 914 metres (500 fathoms) off Mount Erebus. 



ROSSKLLA ANTARCTICA. 



(Plate I., figs. 1 to 4, and Plate IV., figs. 2a to g, and 3a to k.) 



i -;.' RttttUa antarctita, Carter (I, p. 401), pi. zxi.). 



(2, p. 114, pi. x., fig. 4). 

 187 F. E. Schalze (6, p. 139, pi. lv.). 



Three specimens of this species were obtained. They were brought up in the 

 same haul from Winter Quarters, No. 10 hole, 130 fms. The specimens show a 



canals to the primary rays, and the cpine-like nature of the secondary ray*: PI. IV., fig. 3d 4 -* chows an 

 hcucliii-like luoooxyhcxanter with the axial canal* extending but a very ghort distance from the centre, the rest 

 of each ray being olid. PI. VII., fig. Ih, shows a monoducohexaster with the axial canals extending only to the 

 end of the basal thick portion of each ray. PI. IV., fig. 8d* shows three spheroidal reduced hexasten in which 

 the primary rays have disappeared as rays, while the secondary rays remain as one or more spines, or oven 

 spheres, attached to the central sphere, the axial canals being confined to the central node or sphere. II. IV.. 

 fig. 8d' (on the left edge of the plate) shows a monoxyhexaster in which one of the six secondary rays is Winning 

 reduced, thi* being a stage on the way to bocotuing a spheroidal reduced hexaster. 



t The descriptive term " capitulum " is suggested for the enlargement or swelling at the distal end of the 

 primary rays of calyoocomes, aspidopluiuicomes. strobilocomes, microdiscobexasten, etc. The shape of the 

 " capitulum " in these spicoles caUs to mind the reoeptaculuiu and capitulom of the Composite. 



2 H '2 



