ALCYOXARTA PROM SIXGAPOIIE. 507 



Older ALOYONACEA. 



Family A l c y o x 1 1 d .e. 

 Genus Scleropuytum. 

 Sc. PixxuLATUM, sp. u. (PI. LXII. iig. 7 ; PI. LXIII. fig. 10.) 



A single complete colony was taken just below low-tide mark 

 from Blakang ]\Ifiti. 



In its form and mode of branching the colony closely resembles 

 Sc. ]xdmatum Pratt (1903). As in the last-named species, the 

 colony (tig. 7) is erect, branched, and shows a marked lateral 

 compression. The total height is 88 mm., of which the stalk 

 comprises 45 mm. The diameter of the stalk is 31x11 mm,, 

 and that of the capital um is 60 x 35 mm. The stalk divides at its 

 distal end into two almost equal primary branches. From these 

 branches spring numerous secondary lobes which are arranged 

 in no definite order. The secondary lobes frequently show 

 lateral compression in their proximal regions, but their termi- 

 nations are usually bluntly conical, Avhile a few are reniform. 

 The length of these lobes is 12-20 mm., and their diameter 

 6-9 mm. 



The colour of this specimen in alcohol is slate-grey. The 

 consistency is tough ; the stem is hard and brittle, but the 

 secondary lobes are soft and fleshy. 



The autozoids are of a brown colour and are uniformly scattered 

 over the surface of the secondaiy lobes. The average distance 

 between two adjacent polyps is "6 mm. Autozoids are also found 

 on the primary branches almost down to the level of the stalk, 

 but in this region the distance between them is very much greater, 

 viz. 3-4 mm. Many of the autozoids are more or less expanded, 

 but none of them are situated on raised rounded areas such as 

 occur in Sc. ^j«^???.«^it?». The anthocodipe are of medium size 

 when compared with those of the genus Sclero])hytum as a whole ; 

 the diameter of an expanded crown is 1 mm., but the polyp-heads 

 appear only half that size when contracted. 



The tentacles (fig. 10) form the distinctive feature of this 

 species. They ai'e "55 nun. in length, compressed, and expanded 

 at the distal end. There is a single row of free well-developed 

 pinnules on each side of a tentacle. The pinnules ai-e "06 mm. 

 in average length, but the larger ones attain a. length of "10 mm. 

 and a breadth of "035 mm. The larger pinnules ai'e those which 

 are placed third, fourth, and fifth from the distal end ; they 

 become shorter as they approach the base of the tentacle. There 

 ai'e about twelve pinnules in each row. 



The stomodoeum is long and convoluted. The mesenteries 

 and mesenterial filaments are well marked. No sexual organs 

 were observed. 



The siphonozoids, if present, are extremely degenerate. A 

 veiy few minute diverticula of the superficial canals, which point 

 in the direction of the surface, but never open to the extei'ior, 



34* 



