309 



in groups in a single layer, with the smallest in the middle. They 

 measure ca. 80 — 140 [i in diameter. The rods in the skin are more 

 or less regularly C-shaped bodies with enlarged ends. The rods may 

 be either folded-serrate or spiny in the ends, and probably this may 

 prove to be a usable character for separating different forms form 

 each other, but then we must be sure that the rods are not attacked 

 by the preserving fluid. Fig. 65. 13 shows the rods from the skin 

 of the large specimen with the peculiar calcareous ring. In this 

 specimen the ends of the rods are not spiny, the small knobs 

 on their ends, when seen from the end of the rod, showing as 

 distinct transversal folds. In others of the specimens the rods are 

 irregularly spiny, but these specimens appear to be faintly attacked 

 by the preserving fluid. The rods in the tentacles are large and 

 usually slightly bent. Their ends are distinctly swollen and full of 

 blunt spines. The figure (Fig. 65. 12) shows tentacle-rods from 

 the same specimen, from which the figure of the rods from the 

 skin is taken. In other specimens the tentacle-rods are often un- 

 branched, though they are of the same size and shape. In the 

 longitudinal muscles, but not in the polian vesicles and the gonads 

 of the specimens examined, there are small oval calcareous bodies 

 (Fig. 65. 14). 



Probably the large specimen will prove to represent a distinct 

 species, but for the present it will be preferable only to mention 

 its differences from the other species. 



Polycheira echinata n. sp. 

 Koh Lorn. 9. III. 1900. 1 specimen. 



The single specimen at hand is a very young one. It is quite 

 colourless and does not measure more than 1,5 cm in length. It 

 has 17 tentacles each with three pairs of digits. The calcareous 

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

 (Fig. 65. 9). There are four polian vesicles and a single stone- 

 canal. The madreporite is quite like the madreporite in rufescens, 

 only, in accordance with the minute size of the specimen, much 

 smaller. The gonads are undeveloped vesicles, but distinctly branched, 

 and the genital duct opens a little behind the dorsal tentacles. The 

 alimentary canal has a loop and on the mesenteries there are ciliated 

 funnels. These are always united into small clusters (Fig. 65. 3) 



