of the National Antarctic E.t'pedition. 281 



mammillje ; surface finely reticulate and finely hispid. 

 Colour creamy white in spirit. Consistence soft, the tissues 

 being' easily torn. The flesh reddish (but soon decolorized), 

 and showing the glistening white strands of the skeleton. 



Oscules in form of wide, thin-walled, cylindrical chimneys 

 with rather jagged upper edges^ about 1 cm. in height and 

 1-2 cm. in diameter. 



Skeleton. — Ectosomal : a network of triangular meshes 

 formed by bundles of oxeas, the strands being about *35 mm. 

 thick and the meshes about "5 mm. across. Main skeleton 

 formed of long thick anastomosing fibres, which attenuate 

 gradually from I'o mm. in thickness and break up a little 

 below the surface into panicles of much finer fibres, which 

 support the dermal membrane and penetrate the strands and 

 nodes of the dermal reticulum, giving rise to a finely hispid 

 condition of the surface. Parallel groups of oxeas scattered 

 in the choanosome. 



Spicules. — Megascleres : oxeas, 850 X IG 25 fi, sliglitly 

 curved, rather abruptly pointed at one end and more tapering 

 at the other. These oxeas form the fibres and also are 

 gathered into bundles, one spicule in length, of parallel oxeas, 

 sciittered in the choanosome. 



Microscleres: large anisochelaj palmate, 105x50 /x, sepa- 

 rate or in rosettes, usually with an angular bend in the 

 shaft ; with a triangular upper tooth 60 yu, long, about the 

 same length as the upper alte, which latter are very wide. 

 AVith the lower tooth oblong, 12-8 /x high, with a sligiitly 

 convex edge ; in one of the specimens this edge is produced 

 into a denticle. 



A smaller kind of anisochela^ palmatse, 47 /j, long and 17 /u. 

 broad, at the upper end, with a long oval tooth 20 fx long- 

 extending below the alte. 



Trichodragmata, 62x12^, the trichites being very fine, 

 sharply pointed oxeas. 



There are three fine specimens of this species, the largest 

 forming a thick fiubellate body 17 cm. high, 11 cm. broad, 

 and 7 cm. thick. 



The mamnnlla3 are on an average about '75 cm. in height, 

 and 1 cm. in diameter at the base. The new species bears a 

 very close resemblance to ]\[ycale magellanica, Ridley, which 

 likewise has a mammillated, finely reticulate surface and 

 glistening skeletal fibres, but here the surface is smootli and 

 not hispid, and the megascleres are styles, or subtyles, such 

 as are normally found in the genus Mycale. The microscleres 

 also are different in the two sj)ecies. 



A second species of Mycale with oxeate megascleres v 

 Ann. c£; Mag. N. Hist. Ser. 7. Vol. xx. VJ 



