63 



Acanthomuricea spicata, n. sp. Plate IX. fig. 12. 



A small complete colony 55 mm. in height, greyish-wliitr in colour. 



The branching is mainly in one plane, but small twigs with two or three 

 polyps arise at right angles to this plane chiefly from the main stem. The 

 branches arise alternately at wide intervals. There is a flat spreading ba>.-d 

 attachment. 



The axis is horny, cylindrical, and marked by longitudinal striae. Its basal 

 diameter is 1 mm. 



The verrucas are crowded, and occur all over the stem and bram-ln- 

 without any obvious arrangement. On one branch they leave a ban- strip along 

 one side, and bare patches are seen here and there on the stem. There are 

 clusters of verruca; at the origins of small branches, and there are always two 

 divergent verrucse at the tips. The polyps are long, 27 mm. in height even in 

 the partially retracted condition. On the lofty conical anthocodiae the spieules 

 are arranged in a crown with long points. The crown consists of four to five rows 

 of small transverse spicules ; each point has throe spicules, two converging and one 

 in close connection. On the aboral surface of the tentacles there is a narrow band 

 of longitudinally arranged spicules, and there are smaller forms closely packed on 

 the sides and directed towards the bases of the pinnules. 



The verruca) are from 1'8 to 2'2 mm. in height and formed of broad spieule-. 

 the upper ends of which project slightly and produce a rugged surface. 



The rough bark-like cceuenchyma is formed of one layer of rough scales like 

 ctenoid fish scales which are dovetailed into one another. 



The spicules of the verrucaj and of the anthocodiae consist of plates with a spine, 

 irregular discs, elongated triangles with broad bases, rods, spindles, and golf-club 

 forms. All are covered by warty protuberances. The following measurements 

 were taken of length and breadth in millimetres : 



1. Plates, 1 "Ox 0-45; 0'9x0'4. 



2. Discs, 0-85x0-55 : 07x0'35. 



3. Triangles, 0-9x0-4; 0'8x0'3. 



4. Rods, 0-6x0-1 ; 0'5x0'06; 0'3x0'05. 



5. Spindles, 0-9x0-09 ; 0'4x0'06. 



6. Golf-club forms, MxO-12; O'OxO'l. 



The spicules of the ccenenchyma are spindles with large expansions (sometimes 

 foliar) on one side, irregular discs, and somewhat flattened bars. Their measure- 

 ments are : 



1. Spindles, 1-0x02; 0'8x0'2. 



Foliar expansion of spindles, 0'4xO"12; 0"2xO"23. 



2. Discs, 0-6x0-4; 0'6x0'35; 0'4xOM. 



3. Bars, 0-5x0-19; 0'45x0'175. 



