THE ALCYONARIA OF THE MALDIVES. 507 



distinguished in stained preparations. The mesenteries are large and well developed in all 

 the species which I have examined. The ventral and lateral mesenteries are provided with 

 very stout, rounded mesenterial filaments, which are similar to those of the genus Lohophytum, 

 but are larger and much more strongly marked than in the genus Sclerophytum. The 

 dorsal mesenterial filaments are ver}' long, and are grooved and ciliated as in many other 

 genera of the Alcyonaria. 



Zoochlorellae are fairly numerous in the endodermal tissues, canals and zooid cavities in 

 all the species. In addition, rounded cells of a yellow colour occur in glaucum and latum. 



Canal System. The canal system of this genus has been described and figured by 

 Moseley (1881). It is similar to that of Lohophytttin, but differs from Sclerophytum in the 

 absence of a special supei-ficial system. It is to a certain extent homologous with' the 

 internal system of Sclerophytum. In Sarcophytum the principal longitudinal vessels are direct 

 prolongations of the siphonozooids. In Sclerophytum, however, the siphonozooids terminate in 

 the large vessels of the special superficial -canal system, and as a rule are only indirectly 

 connected with the longitudinal vessels of the internal canal system (p. 519). 



The longitudinal vessels run more or less parallel with the longitudinal axis of the 

 autozooids, and send off numerous branches, which may terminate in the coelenteric cavity 

 of a neighbouring zooid, or ramify and anastomose in the substance of the mesogloea, and 

 form a complete network. Some of the branches end in solid cords and strands in the 

 mesogloea, in a manner described by Ashworth in Xenia (1899, p. 190). The strands and 

 cords are not indicated in Moseley's figure. I found it impossible to perceive cilia on the 

 walls of the vessels of the canal system. 



In addition to this system of canals neighbouring autozooids are connected by means 

 of short, straight canals which are provided with fairly long cilia (fig. 3). These vessels are 

 described and figured by Moseley, but are not described as being ciliated. I have observed 

 similar ciliated vessels in Lohophytum, in living Alcyonium, in which they are less numerous, 

 and in Sclerophytum, in which they are very few in number. 



Growth. In all the species of the genus which I have examined the autozooids are 

 most numerous at the margin of the capitulum (fig. 1), but in this portion of the colony 

 they are usually smaller and appear to be younger than elsewhere. Growth, by the budding 

 of new autozooids, is most vigorous in the same part. Where it is very rapid the margin 

 is often thrown into folds as in Schenk's figure S. plicatum (1896, Taf ii. fig. 12). Often 

 a young colony can be distinguished from an older one by the rounded, unbroken contour 

 of the margin, but in both specimens of tenuis, which have attained a considerable size, the 

 capitulum is flattened, slightly concave, and the margin unbroken by folds (fig. 9). The 

 siphonozooids are not very numerous at the margin, but are most common in the middle 

 of the capitulum. They are apparently budded off from the endodermal canals usually in 

 the proximity of the food-supplying autozooids. Young specimens of Sarcophytum and Loho- 

 phytum are usually mushroom-shaped, and are very similar in appearance, so that at first 

 sight a young Lohophytum may be easily mistaken for a Sarcophytum. After carefully 

 examining all the young specimens in this and in the other collections I find in every case 

 that in Sarcophytum autozooids are most numerous at the margin of the capitulum (fig. 1), 

 while in Lohophytum autozooids are least numerous, and siphonozooids most numerous at the 

 margin (fig. 7). As growth of the capitulum proceeds in both genera chiefly by the budding 

 of new autozooids, the growth of the colony in Sarcophytum is most vigorous at the edge 



65—2 



