256 



They are more regularly shaped (Fig. 46. 6) and measure ca. 

 30 — 40 ^ in length. In the exterior side of the tentacles there 

 are some small oval, usually brownish bodies (Fig. 46. 13). 



Protankyra bidentata is a well marked species, easily recognized. 

 The type of it was a two inches long fore-end, and as seen in the 

 description above one could not expect that Woodward & Bar- 

 rett should be able to find more than one size of anchors and 

 anchor-plates in it. For this reason Clark in "The Apod. Holoth." 

 has placed bidentata among the species with but one size of anchors 

 and plates in the skin. The first to observe more than one sort 

 of anchors and anchor-plates in this species is Thé el. He writes 

 in the description of Synapta distincta (— bidentata) that "most of 

 the anchors have a length of 0,23 mm, but there are some scattered 

 ones to be seen, which measure about 0,4 mm", but as his spec- 

 imens were only fragment he has not been able to make a closer 

 examination of this feature. In "Synaptiden von Misaki" Oh shim a 

 further writes that "Bei Protankyra bidentata kommen Anker und 



Ankerplatten von stark verschiedener Grösse vor und die 



grösseren liegen ausschliesslich in den Interradien, während die 

 kleineren sich immer nur auf die Radien besc lränken". Thus there 

 can be no doubt that Protankyra bidentata (Woodward & Barrett) 

 belongs to the species with more than one sort of anchors and plates 

 in the skin. From the two other species of this group, pseudo-digitata 

 Semper and bankensis Ludwig, bidentata is distinguished especially 

 by the shape of the ciliated funnels, of the deposits in the tentacles 

 and the anchors and plates. 



There is in my mind no doubt that Synapta distincta v. Maren- 

 zeller is synonymous with bidentata, but I do not suppose that mo- 

 lesta Semper can be referred to this species. Synapta molesta Sem- 

 per seems to be closer related to pseudo-digitata Semper, and most 

 likely it will turn out to be identical with that species. 



Protankyra pseudo-digitata (Semper). 

 Synapta pseudo-digitata. Semper. 1868. Die Holothurien. pag. 9, 

 Pl. IV fig. 12. 



? Synapta molesta. Semper. 1868. Op. cit. pag. 9, Pl. IV fig. 13, Pl. V 



fig. 22. Pl. VI fig. 8, Pl. VIII fig. 3. 

 Synapta innominata. Ludwig. 1875. Beiträge zur Kenntniss der Holo- 

 thurien. pag. 79, Pl. VI fig. 4. 



