THE APODOUS HOLOTHUEIANS 111 



DiSTBiBXJTiON — Eeported only from the Bay of Batavia (Sluiter). 



Remarks. — Sluiter distinctly says that the absence of calcareous particles 

 could not be due to impure alcohol, for he examined the animal when "ganz 

 frisch." Ostergren ('986) expresses the opinion that this is only a regenerating 

 individual of some synaptid, but that would not account for the entire lack of 

 calcareous particles. Although the type specimen is still unique, it must bo al- 

 lowed to stand as a valid species until we have more light on the subject. 



DACTYLAPTA, gen. nov. 



(SaKTi'Aa^ fingers, + aTTTw, to fasten or liincl; in refrrcnce to the tentacles and to eor- 

 respond to Synapta, etc.) 



Tentacles digitate, 12. Digits only four, two on each side, as in Protan- 

 kyra. Calcareous particles, only short, curved rods, scattered in the skin. 

 This genus is instituted for the following imique species. 



Dactylapta dubiosa. 



Anapta ( ?) duhiosa Koehler and Vaney, 1905, p. 109. Calcareous particles and cal- 

 careous ring, pi. XV. figs, 11-13. 



Length. — 30 mm. and more ; only an anterior fragment known. 



CoLOB. — Brown. 



Distribution. — Reported only from Gulf of Bengal, T.j8 m. (Koehler and 

 Vaney). 



Rbmaeks. — Although there is at least a possibility that this specimen, ui)on 

 which a new species and genus is based, is only a diseased or abnormal Pro- 

 tankyra, we must for the present admit its validity. The form of the tentacles 

 and of the calcareous deposits shows that the species bears the same relation to 

 Protankyra that Anapta does to Leptosjmapta, and it must therefore be placed 

 in a distinct genus, so that this relationship may be emphasized. 



RHABDOMOLGUS Keferstein, 1862. 



Tentacles without digits, simply "am Eande leicht gelappt," 10. Carti- 

 laginous ring wanting. Calcareous ring remarkably weak. Polian vessel one. 

 Stone-canal one, but non-calcareous. Ciliated funnels wanting. Calcareous par- 

 ticles wholly wanting. Sexes separate (?). 



The remarkable holothurian upon which Keferstein based this genus is in 

 many ways much like a young synapta, and since no other zoologist met with it, 

 each succeeding writer has been more and more inclined to reject the genus and 

 species altogether. Ludwig ('98&) places it in a foot-note and doubts its va- 

 lidity, and Ostergren ('98&) ignores it entirely. It was therefore a matter 

 of considerable surprise when Ludwig ( :05) announced the rediscovery of 

 Rhabdomolgus, and his complete report is awaited with keen interest. 



