129 



plates are, as the one figured, quite normally formed, and then much 

 like the plates in serpentina, but by far the larger part of the plates 

 are very different from that regular form, and some have even 

 large side-holes as the plates in Euapta (Fig. 6. 5). Such side- 

 holes are also found in Oph. lineata, but as, on the other hand 

 some of the plates in Euapta tobagoensis are lacking the side-holes 

 the presence or absence of these holes does not afford a reliable 

 generic character. The miliary granules are rosettes, which are 

 lying so densely all over the skin that, even when cleared in 

 balsam, it is nearly quite intransparent. Rods are totally wanting 

 both in the oral disk and in the tentacles. 



This species is the most closely related to serpentina Johs. 

 Müller, but differs distinctly from that species in the variable shape 

 of the anchor-plates and in the absence of rods. From the other 

 species without a web between the digits it differs in the shape of 

 the anchor-plates and in the shape and colour of the calcareous ring. 



Opheodesoma grisea (Semper). 



Synapta grisea. Semper. 1868. Die Holothurien, p. 11 Pl. IV f. 6 — 7. 

 Euapta grisea. 0stergren. 1898. Das System der Synaptiden, pag. 113. 

 Opheodesoma grisea. Fisher. 1907. The Hawaiian Holothurians, pag. 723. 

 — — Clark. 1908. The Apodous Holothurians, pag. 75. 



1924. The Synaptinae, p. 466 Pl. II f. 1—3. 



Zebu. 20.IV. 1900. 1 specimen. 



Pearl Harbour, Honolulu. 5. V. 1915. 8 specimens. 



Saparoea Bay. 10. III. 1922. 19 fms. Sand. mud. 1 specimen. 



Edam, Java Sea. 5.IX.1922. Coral reef. 1 specimen. 



The specimens at hand measure from 15 to 22 cm in length, 

 but the largest specimen is lacking the posterior end, and may 

 have measured ca. 35 cm in length. They are all dark mud-grey, 

 distinctly darker on the dorsal than on the ventral side. They 

 have 15 tentacles and the digits are not united by a web. On 

 the oral disk no eye-spots are seen, but on a more careful prepara- 

 tion they are seen to be quite as well developed as in the other 

 species of Opheodesoma. The lacking of eyes in Clark's specimens 

 of grisea described in "The Synaptinae" therefore may be due to 

 a less exact examination. The cartilaginous ring is large and the 



Vidensk. Medd. fra Dansk naturh. Foren. Bd. 85. 9 



