286 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 11 



acra; ventrally cylindrical, dorsally more papilliform. Calcareous ring 

 delicate with very elongate ribbonlike interradialia. Color white to 

 golden brown, mostly with dark appendages and tentacles. Skin soft, 

 thick, gelatinous. 



Spicules few, as scattered tables, stout or delicate ; in the type species 

 a few buttons present, deformed or incomplete, suggesting clumsy C- 

 shaped bodies. 



Type species: Labidodemas semperianum Selenka. 



Remarks: Three species previously described were united by 

 Sluiter (1901) under one name. At the same time he established a 

 rather doubtful new species without any spicules. Ludwig's Holothuria 

 pertinax (see Panning, 1934, III, p. 75, text-fig. 57) is withdrawn as 

 a synonym of Labidodemas semperianum. A new species of Labidodemas 

 was described from the Panamic region in 1938. 



Labidodemas americanum Deichmann 1938 



PI. 1, fig. 5 



Labidodemas americanum Deichmann, 1938, p. 363, text-fig. 1. 



Diagnosis: As for the genus, but spicules delicate tables with four 

 central holes, a circle of about ten marginal holes, of which some may 

 be imperfect, and often a few blunt marginal teeth ; spire sometimes re- 

 duced to four knobs. Large cylindrical feet on the ventrum with a large 

 end plate and a few small plates with 4 or 5 holes, possibly representing 

 reduced tables; the dorsal appendages papilliform and seemingly lack- 

 ing the end plate completely, but with small plates in the walls, similar 

 to those in the ventral feet. 



Color varying shades of golden brown, inclining toward greenish; 

 usually dark brown appendages and tentacles, in some specimens faded. 



Type: Museum of Comparative Zoology. 



Type locality: Costa Rica, Jasper Island. 



Distribution : Known from Galapagos Islands, Cocos Island, Costa 

 Rica, and Espiritu Santo Island, Gulf of California. 



Depth : Shore. 



Specimens examined: The types and the 13 specimens collected by 

 the Hancock expeditions — Galapagos Islands, 8 specimens from 4 sta- 

 tions; Cocos Island, 2 specimens; Espiritu Santo Island, 3 specimens. 



Remarks: The Hancock material ranges in length from 2 to 7 cm 

 and varies somewhat in color ; in some specimens the ventral appendages 

 are almost white. The species is well characterized and quite distinct 



