NO. 2 DEICHMANN : HOLOTHURIOIDEA ; PART II, ASPIDOCHIROTA 289 



crowded layer of tables with about 8 holes in the disk, often with 

 smaller holes intercalated between them; spire low with numerous 

 spines on top. Buttons broad oval with three to five pairs of small holes. 

 Ventral feet with large end plate and broad plate-like supporting rods, 

 often with slitlike holes. 



Types: Semper's cotypes are in the Museum of Comparative Zoo- 

 logy, as well as the types of H. L. Clark's Holothuria frequentiamensis 

 and H. altimensis. 



Type localities: Semper's types came from Samoa, as did Holo- 

 thuria excellens. Clark's types came respectively from Clipperton Island, 

 eastern Pacific, and Torres Strait, Australia. 



Distribution: From the eastern coast of Africa westward to the 

 tropical coasts of Central America and Mexico. 



Depth : Shore, mostly under flat rocks in pools. 



Specimens examined: The paratypes and types listed above, and a 

 large series from various localities in different collections, including 

 Bedford's material in the British Museum. One hundred and eight 

 specimens from 22 stations, collected by the Velero III. Of these, 46 

 came from the Galapagos Islands, one from Cocos Island, 8 from Clar- 

 ion Island, 25 from Panama, 15 from Costa Rica, and 13 from the 

 coast of Mexico, as far north into the Gulf of California as Espiritu 

 Santo Island. The species was not taken at San Lucas or along the west 

 coast of Lower California. Its absence in Socorro Island may be acci- 

 dental, as the species is common both in Clarion Island and Clipperton 

 Island. 



Remarks: The Velero material ranges in length from 2 to 8 cm; 

 but as the largest individuals are somewhat contracted, they probably 

 measured at least 10 cm when expanded. The color shows some varia- 

 tion from light brown, almost yellow, to dark purplish brown or black. 

 In many localities the individuals had undergone transverse division, so 

 one finds the usual "stumpy" specimens with too large a tentacle crown 

 and closed posterior end, or a posterior end with a regenerating, pale 

 anterior end, as described by Deichmann in 1922. 



The spicules are distinctly different from those of the smaller Micro- 

 thele parvula from the West Indies and Bermuda, as previous studies 

 have shown. In addition, W. K. Fisher found that the Cuvierian organs 

 were ejected as "long sticky threads" in M. parvula, while Mortensen 

 found them to be discharged as minute vermicellilike fragments in M. 

 difficilis (verbal communication). Whether the green pigment so char- 



