THE APODOUS HOLOTHURIANS 81 



and the other by vivipara. Should these groups be separated in the future, the 

 former would of course be called Chondrocloi'a, unless indeed Forskal's vittata 

 is rediscovered and found to belong in that genus, which would then, appar- 

 ently, have to be called Tiedemannia.^ 



Key to the Species of Synaptula. 



A. — Tentacles 15, with numerous digits (20-30 pairs) united at their bases by a thin 



membrane; color uniform dark brown or violet nigra 



AA. — Tentacles 12-13 (often 15 in recta, perhaps normally in adults), with 10-30 pairs of 

 digits (pi. VI, fig. 19). 

 B. — Tentacles normally 12, with 10-20 pairs of digits; viviparous; occidental. 



HYDRIFORMIS 



BS.— Tftitacles usually 13 (often 15), with 10-30 pairs of digits; not viviparous so 

 far as known; oriental. 

 C. — Gonads unbranched; polian vessels few; tentacles very long and slender, 



with about 10 pairs of digits indivisa 



CC. — Gonads branched; polian vessels mimerous; tentacles not excessively elon- 

 gated. 

 D. — Miliary granules very minute, simple oval bodies usually arranged 



in circles; color gray, with darker spots psara 



DD. — Miliary granules irregular rosettes. 



Color, very variable; digits very short recta 



Color, dark hrown-violet. longitudinally striped with white ; digits 



long and united by a delicate membrane virgata 



/144.— Tentacles 10 



Digits numerous (12-15 pairs), long; color, milk-white oi ith a rosy tint, .lactea 

 Digits few (5-6 pairs), short; color variable, but not whitj reticulata 



Synaptula nigra. 



Synapta nigra Semper, 1868, p. 12. Calcareous particles, pi. iv, fig. 9. 

 Synapta orsinii Ludwig, 18866. p. 33. 

 Synapta reciproquans Herouard, 1893, p. 137. 

 Chondroclcea nigra Ostergren, 1898&. 

 Chondroiloca orginii Ostergren, 18986. 



Length.— 100-200 mm.; Semper's type was only 60 mm. 



Qon)R.— Dark brown, deep brownisli red or violet, sometimes with a black 

 longitudinal stripe on the outer surface of each tentacle. 



Distribution.— Reported from Bohol, Philippines (Semper); Australia, 

 and Eed Sea (Lampert) ; Margalla Bay, Assab (Ludwig), and Fontaine de 

 Moise, Red Sea (Herouard). Probably occurs along the entire southern coast 

 of Asia, throughout the East Indian Archipelago, and southward to Australia. 



Remarks.— This is one of the least-known members of the genus, no addi- 

 tional information regarding it having appeared since Semper's original de- 

 scription, save for the localities given by Lampert ('85), the description of a 

 specimen from the Red Sea as a new species {orsinii) by Ludwig ('86), and 



Tor an excellent discussion of this point see Fisher (-.07), pp. 718-719. 



