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



bent spindles, somewhat transparent and armed with numerous spines. In the body they 

 often assume a more club-like form, one end becoming truncated and a little thickened; 

 here they form eight rows, in each of which two spicules converge always together. 

 Each of these rows subtends a tentacle. The colleret contains spiny, feebly bent, rod-like 

 spicules which form a peripheral ring, the margin of which is composed of eight groups 

 of spicules. The basal portion of the tentacles which forms the operculum is situated at the 

 point of contact of two groups, formed from several rows of spicules converging upwards. 

 The axis is soft, horny, fibrous ; the terminal branches are soft and pendulous. 



Anthomuncea argentea, n. sp. (PI. XXIII. fig. 1). 



The main stem branched in one plane rises from a flat base ; it consists of a principal 

 stem with branches arising at angles, which do not give ofi" branches in their turn, and there 

 are four large branches which give ofi" simple lateral twigs like the principal stem. The 

 principal stem and branches are bent in various ways, the branches at their apices are soft 

 and pendulous, at their terminations they are onlj' slightly thickened. The main stem 

 reaches the length of 400 mm., at the base it has a thickness of 5 mm. The small lateral 

 branches are from 1 mm. to 20 mm. The large branches are 220 mm. in length and have 

 a thickness of 3 to 4 mm. at their origin. The coeneuchyma is everywhere very thin 

 and almost transparent. The hyaline spicules, which only form a thin layer, give it a 

 silvery appearance. The polyps on the stem and branches are at intervals of from 2 to 

 2 '5 mm. They are arranged spirally and so that three to four polyps form a spiral. 

 They are c3-liudrical, rising perpendicularly 2 mm. high ; 1 mm. constitutes the caly.x, 

 and 1 mm. the opercular portion near the colleret. The young polyps at the apex of 

 the branches arise directly behind the blunt stolon which forms the termination of the 

 branches and the twigs. The spicules of the coeueuchyma are chiefly curved spindles with 

 short pointed spines; length by breadth 0"5-0"04 ; 0"3-0'05 mm. The calycine spicules 

 assume a slightly club-like form and are in pairs, the blunt ends converging ; the length by 

 breadth of these spicules is 0-25-0-04 ; O-S-O'Oo ; 0-3-0-045 mm. At the colleret the 

 spicules are feebly curved rods rounded oflf on both sides, and armed with delicate spines ; 

 length by breadth 0-58-0-03 ; 0-4-0-03 ; 0-33-0-025 mm. The basal portions of the 

 tentacles which form the operculum are armed with at least from four to five rows 

 of spicules placed en chevron, which have a spindle-like form and are feebly bent. Their 

 length, taking those from the base to the termination of the opercular region, is 

 0'38-0'22 ; 0"2 ; 0'18 ; O'lG mm. The axis is horny, fibrous, a little compressed, in the 

 smaller branches it is soft and pendulous. Colour brouTi. The colour of the coenenchjTna 

 is glistening white. The polyps are brown. 



Habitat. — Station 307, off' Port Grappler, Patagonia ; depth, 140 fathoms ; bottom, 

 blue mud. 



