132 



The anchors (Fig. 7. 4) measure ca. 350 ^ in length by ca. 

 210 (i in width. The stock is branched and on the vertex there 

 are minute knobs. There are two typical forms of anchor-plates, 

 one with side-holes and one without, and between these there 

 are many different intermediate stages (Fig. 6. 10-11). Those 

 with side-holes (Fig. 6. 13) measure ca. 270 ^ in length by ca. 

 210 /a in width, those without side-holes (Fig. 6. 12) ca. 240 fi in 

 length by ca. 180 fi in width. Both sorts of plates have the common 

 two rows of large knobs around the holes. The miliary granules 

 are rosettes which are gathered in large heaps. 



As this fragment is lacking the madreporic canals and has the 

 two mentioned sorts of anchor-plates the generic determination is 

 not at all certain, but as the general appearance of the anchor- 

 plates is more like that of the plates in Opheodesoma than that of 

 the plates in Euapta, I have referred it to Opheodesoma. That the 

 specimen is at any rate a valid species, different from all the 

 hithertho known species of both Opheodesoma and Euapta appears 

 from the very characteristic shape of the anchor-plates and the 

 peculiar colour. 



Euapta 0stergren. 



0stergreen. 1898. Das System der Synaptiden, pag. 112. 

 Sluiter. 1901. „Siboga" Holothurien, pag. 123. 

 Fisher. 1907. The Hawaiian Holothurians, pag. 721. 

 Clark. 1908. The Apodous Holothurians, pag. 72. 

 — 1924. The Synaptinae, pag. 462. 



Genotype: Synapta godeffroyi Semper. 



Remarks: In the description of Opheodesoma variabilis it is said 

 that the presence or absence of the side-holes on the anchor- 

 plates may not be a reliable generic character. For this reason 

 the two best characters for separating Euapta from Opheodesoma 

 are the small number of madreporic canals and the large size of 

 the rods in the oral disk and the tentacles. 



In Opheodesoma the rods are usually confined to the oral disk, 

 and when tentacle-rods are present they are smaller than the 

 oral-rods. Further the surface of both oral- and tentacle-rods in 

 Opheodesoma is always quite smoth. In Euapta there are always 

 rods in the tentacles and these are larger than those in the oral 



