50 THE VOYAGE OF B.M.S. CHALLENGER. 



Dermal triradiatt spicules.— Sagittal ; all rays of the same diameter, the proportion between 

 the length and the thickness varying from 10 : 1 to 18 : 1 ; lateral rays curved forwards, 

 reaching 0-5 mm. in length, each forming with basal ray an angle of about 120° ; basal 

 ray straight, its length not exceeding that of lateral rays, usually still shorter. 



Stout acerati spicules.— Either spindle-shaped or of irregular form (PI. V. fig. 3e); straight or 

 slightly curved, some reaching over 2 mm. in length, with a diameter of 01 mm., most 

 not exceeding 1 mm. in length and - 06 mm. in diameter. 



Fine aeerate spicules of the peristome. — 2 mm. and above in length and 0*0025 mm. in diameter, 

 occasionally still thinner, sharp-pointed at both ends, the free end being, however, broken 

 off in most cases. 



Colour. — White. 



Habitat. — Bahia ; shallow water. 



Anamixilla, n. gen. 



Syconicte without any special tubar skeleton, the supporting spicules of the 

 parenchyma disposed in it like those in the Leuconidae ; in most cases, however, more or 

 less parallel to the outer surface. 1 



Anamixilla torresi, n. sp. (PL IV. figs. 2«-2c). 



The single specimen of Anamixilla torresi of the Challenger collection presents a 

 colony of tubular individuals of similar aspect to Amphoriscus fiamma ; some individuals 

 are bare-mouthed, some mouthless. The thickness of different individuals varies from 

 1 to 9 mm. ; the width of the walls is more constant, reaching 1 mm. on the average. 

 The inner surface is slightly roughened by the apical rays of the gastric quadriradiate, the 

 outer surface in a still higher degree roughened by the cortical triradiate spicules. 



Skeleton. — The skeleton consists of gastric quadriradiate, of gastric triradiate, of sub- 

 gastric triradiate, of parenchymal triradiate, and of dermal triradiate spicules. 



ic quadrira liaii spicules. — All rays of the same diameter (0 - 02 mm.) ; basal ray straight, 

 either sharply or bluntly pointed, of conical form, length varying from - 16 to 04 mm., 

 occasionally rather thicker than lateral rays, forming with each of these an angle of about 

 115' ; lateral rays curved outwards, often slightly undulating, tapering from the base to 

 a sharp point, usual length 035 to 0-4 mm. ; apical ray curved, sharply pointed, its length 

 not exceeding - 06 mm. 



Gastric triradiate spicules. — Piays smooth, tapering from the base to sharp points, reaching 

 04 mm. in length, with a diameter of - 015 mm. ; basal ray straight, lateral rays slightly 



1 With the exception of the snbgastrie triradiate spicules, disposed like those in the genus Amphoriscus, if these 

 he not an exclusive attribute of the only species of the genus hitherto known, Anwm ' cilia torresi. 



