THE ALCYOXARIA OF THE MALDIVES. 529 



Spicules. The species is characterised by the enormous spicules which occur through- 

 out the colony and can be seen with ease through the ectodermal tissues (figs. 29 and 30 sp). 

 The largest are all spindles of the tuberculate type (fig. 31). These spicules have an im- 

 portant bearing upon the form of the colony in that they materially afi"ect its outline. Small 

 clubs are numerous near the surface as in other species. The tuberculate spindles vary in 

 size fi-om 1-5 x 5 mm. to 7 x 17 mm. (fig. 31). They are often somewhat irregular in form; 

 they may be sharply pointed or blunt at each end, many are ridged and are three-sided, 

 some are crescentic, many are curved. All the large spicules are unbranched, in this respect 

 the species differing from any other in the collection. 



When a spicule is seen with the naked eye the general outline appears smooth and 

 unbroken, when examined with a lens the surface appears granular (fig. 31), but when 

 subjected to higher magnifications the gj-anules are seen to be tiny tuberculate warts regu- 

 larly arranged (fig. 31 b, and c), averaging '09 mm. across. A few spindles occur here and there 

 with a few tubercles. 



Packed closely near the surface are the small clubs and a few minute spindles with 

 few tubercles, and a very few irregular tuberculate dumb-bells about "1 mm. in length and 

 "08 mm. in breadth. The clubs are knotted and of varied shape, '12 — '24 mm. long and 

 about '02 mm. broad (fig. 32 a, b, c, d, e). They are apparently the only branched spicules 

 in the species. 



The autozooids, most of which are completely retracted in all the specimens, are more 

 numerous on the lobed (fig. 29) than the cup-shaped specimens, but are proportionately fewer in 

 this than in any other species of the genus which I have examined. This may, to a great 

 extent, be due to the presence of numerous large spicules which run immediately below but 

 parallel with the surface. The autozooids are very minute, and in the retracted state their 

 apertures are difiicult to distinguish even with a lens. In the cup-shaped specimens the 

 polyps appear to be most numerous on the margin of the capitulum. The diameter of a 

 polyp cavity when the polyp is completely retracted is "25 — '.5 mm. The tentacles are ex- 

 tremely short and stumpy, and only very slightly pinnate. They possess spicules in the 

 form of extremely small spindles. The stomodaeum is long, measuring about '85 mm. It is 

 slightly convoluted in the preserved state ; the siphonoglyph is fairly well-marked. The 8 

 mesenteries are very slender, but are clearly marked. All of them have mesenterial filaments. 



The two dorsal mesenterial filaments are of considerable length and are grooved and 

 ciliated as in other Alcyonaria. The ventral and lateral mesenterial filaments are extremely 

 short and are confined to that portion of the autozooid immediately below the stomodaeum. 

 They are similar in form and anatomy to those of other Alcyonaria. Tj'pical Alcyonarian 

 ova, "3 — '5 mm. in diameter, are present in the mesenteries. 



The siphonozooids are extremely degenerate in this species, and are represented by 

 small caeca from the superficial transverse canals. 



Canal Systems. The superficial canal system is strongly marked. The large transverse 

 vessels run in a sinuous course immediately below the ectodermal tissues. Many of the 

 canals are closely apposed on theii- internal side to the enormous spicules which in this 

 species lie so near the surface. These canals have very short vertical caeca towards the 

 surface but they are shorter than Sc. polydactylum and are homologous to the degenerate 

 siphonozooids in other species. The superficial canal system has numerous communications 

 with the internal canal system, which is not so strongly marked as in other species. 



G. II. 68 



