NO. 2 DEICHMANN : HOLOTHURIOIDEA ; PART II, ASPIDOCHIROTA 325 



out, Jaeger's name is invalidated by Quoy and Gaimard's older name, 

 which again is a synonym of Lesson's Holothuria monacaria — so Selen- 

 ka's name must stand. 



13. Theelothuria n. gen. 



Diagnosis: Large spindle-shaped forms, up to 20 cm or more, with 

 20 small terminal tentacles. Conical appendages fairly uniformly dis- 

 tributed in the adult specimens; ventrally the appendages ending in a 

 cylindrical soft retractile tube foot, dorsally in a papilla. Calcareous ring 

 with remarkably tall radials, slightly excavated posteriorly, forming short 

 "tails" ; interradials of the usual type. Color varying in the same species 

 from almost black to pale yellow, with or without large dorsal spots. 

 Appendages surrounded by a narrow white ring, rather inconspicuous 

 in the pale individuals. 



Spicules an outer layer of tables with a circle of marginal holes and 

 blunt, upward-bent spines ; spire low with few teeth ; in older individuals 

 these tables reduced to irregular four-holed plates. An inner layer of 

 irregular buttons with or without a few knobs; in one species the but- 

 tons become gradually smooth with small holes which tend to become 

 obliterated. The ventral feet with end plate and straight to curved sup- 

 porting plates with a row of holes along the sides and often a few knobs. 

 In the papillae the end plate reduced or lacking and the curved rods with 

 fewer holes along the sides. Most individuals have a few huge tacklike 

 tables in the appendages, visible to the naked eye, consisting of a larger 

 or smaller disk with numerous holes and tapering into a tall conical spire 

 sometimes showing traces of being composed of four pillars. In one 

 species the young individuals (3 cm long) lacking the inner layer of 

 buttons but with juvenile tables of the synallactid-type, with cross-shaped 

 disk. 



Burrowing forms rarely taken at low tide, mostly from 10 to 50 

 fathoms. Not common in most collections. 



Type species: Holothuria princeps Selenka. 



Remarks: The group is rather incompletely known and the five or 

 more species known from the Indo-Pacific which appear to belong in this 

 genus may possibly be reduced to two or three. The type species is well 

 known from the West Indies (including its synonym, Holothuria im- 

 perator Deichmann) and we are fortunate in that there is only one 

 species in that region. From Panama one species is described which is 

 clearly separated from the type species, but it is quite possible that it 



