530 CLARK 



Another point shown by the table is that while the Bermudas have 

 among their iS known species not one peculiar ophiuroid, the Gala- 

 pagos, with less than half as many species, have three peculiar forms. 

 This may illustrate, what there is some reason to believe is the case, 

 that the ophiuroids are more variable than any other class of echino- 

 derms, and that " new species " are now forming under the influence 

 of isolation or other suitable conditions, more rapidly than in the other 

 classes. Or it may simply emphasize the fact that our knowledge of 

 West Indian ophiuroids is far in advance of our knowledge of eastern 

 Pacific forms. But whatever the explanation, these facts, though so 

 few, seem worthy of special note. 



THE HOLOTHURIANS OF CLIPPERTON ISLAND. 



With the echinoderms from the Galapagos, Mr. Snodgrass sent me 

 26 holothurians taken at Clipperton Island. This island lies in lati- 

 tude 10° north, and near longitude 109° west. It is the easternmost of 

 the Pacific coral islands. These holothurians represent only two species, 

 nine of them being large black individuals, the others small and red- 

 dish-brown. The former answer well to the descriptions of Holo- 

 thuria atra (Jager), especially as regards the calcareous deposits, but 

 the specimens do not look at all like Semper's figure nor do they re- 

 semble specimens from the West Indies, with similar calcareous bodies. 

 At present, however, there seems to be no recourse but to call them 

 H. atra, though I am confident that no less than three distinct species 

 are now included under that name. The case is very similar to that 

 of H. impatiens and like that will require an abundance of material 

 from all parts of the globe to make a proper assortment possible. 

 The small holothurians from Clipperton Island seem to represent a 

 new species allied to H. captiva Ludwig and H. dijfficilis Semper, 

 the former from the West Indies, the latter from Samoa. For this 

 species I propose the name Holothuria frequentiamensis. 



HOLOTHURIA FREQUENTIAMENSIS sp. nov. 

 Dorsal surface somewhat arched, sparsely covered with papillae ; 

 ventral surface flat, closely covered with pedicels, which show no evi- 

 dence of arrangement in longitudinal rows ; line between dorsal and 

 and ventral surfaces quite clearly marked. Tentacles 20, not peculiar. 

 Polian vessels, 3 or 4. Stone-canal small, single. Calcareous ring 

 not peculiar, similar to that of H. captiva. Cuvier's organs very 

 noticeable, brownish or purplish (in alcohol). Reproductive organs 

 wanting in all but one specimen ; some had evidently eviscerated while 



