307 



Koh Lorn, Gulf of Siam. 9. III. 1900. 72 specimens. 



Saparoea Bay. 10. III. 1922. Rocky shore, at low water. 4 specimens. 



Sebesi. Sunda Strait. 13. III. 1922. The shore, at low water. 2 specimens. 



As to the biology of this species cf. Note pag. 322. 



As said in the above remarks about this genus the collection at 

 hand includes several closely related forms, but as the preservation 

 does not allow any closer study of the finer characters, I must refer all 

 the specimens to Semper's variabilis (— rufescens Brandt), which 

 is however most likely a collective name for several related species. 



The specimens from Koh Lorn are pale greyish and those from 

 Saparoea and Sebesi are nearly blackish-purple. All the specimens 

 have 18 tentacles each with 5 — 7 pairs of digits. The calcareous 

 ring consists of 18 pieces and all the five radiais are perforated 

 for the passage of the nerves. The shape of the calcareous ring 

 (Fig. 65. 8) is not much varying, but a single large specimen from 

 Koh Lorn differs somewhat in the shape of the ring (Fig. 65. 7) 

 from the other specimens. There are 10 — 12 polian vesicles and 

 a single stone-canal. The madreporite is rather long (Fig. 65. 6) 

 and the calcification of it is very folded. The alimentary canal has 

 a large loop and on the mesenteries there are large clusters of 

 ciliated funnels (Fig. 65. 1-2). The clusters are of very varying 

 shape, but usually there are two sorts in each specimen, a large 

 and a smaller one. Whether the smaller ones are younger stages 

 of the large clusters, it is not possible to decide from the collection 

 at hand, but intermediate stages have not been found, and as they 

 are furthermore found in different places I suppose that also the 

 smaller ones may be regarded as fully formed. The funnels them- 

 selves are all of one shape (Fig. 65. 5) and measure ca. 100 /n in 

 length. The large specimen with the peculiar calcareous ring has 

 the clusters slightly different from those in the other specimens 

 examined, the funnels being arranged in two rows on the stem. 

 The length of the large clusters is in this specimen ca. 1 mm, 

 and in the other specimens 0,7—1 mm. The small clusters 

 measure ca. 0,3 mm in length. The gonads are in many of the 

 specimens rather faintly developed, but they are distinctly branched 

 and the genital duct opens on a little papilla close behind the 

 dorsal tentacles. 



The wheels are in uncontracted specimens very regularly arranged 



20» 



