244 HAWAIIAN AND OTHER PACIFIC ECHINI. 



(1906, Mem. Geol. Soc. France, XIV., p. 67) and Mortensen's (1907, "Ingolf" 

 Ech., pt. 2, p. 174) statements that Anapesus Holmes must take precedence 

 over Lytechinus for variegatus and its allies, shows that neither of them has 

 consulted Holmes's paper (1860, Post-Pliocene Fossils S. Carolina, p. 5, PI. II, 

 fig. 2) but each has been misled by Pomel. The mistake of the latter was doubt- 

 less due to the unfortunate error in the "Revision" (p. 167, 168, and 172) by 

 which Anapesus Holmes is made a synonym of Toxopneustes instead of being 

 assigned to Arbacia, to which it is correctly referred on p. 72 of the "Revision." 

 Holmes's excellent figure permits no doubt on this point. It is most fortunate 

 that miliaris may be accepted as the type of Psammechinus for of all the species 

 included by Agassiz and Desor in their subgenus, it is the only one to which the 

 diagnosis given, accurately applies. Mortensen's attempt to fit that diagnosis 

 to variegatus is scarcely convincing. 



As herein limited, Psammechinus includes only the two well-known European 

 species, which may be distinguished from each other as follows : 



Buccal membrane well covered with whitish plates; tuberculation of test, coarse; 



secondary tubercles very large miliaris. 



Buccal membrane completely covered by green or greenish plates; tuberculation of 



test, fine; primary tubercles much larger than secondaries microtuberculatus. 



LYTECHINUS. 



A. Agassiz, 1863. Bull. M. C. Z., I, p. 24. 

 Type-species Cidaris variegata Leske, 1778. Add. ad Klein, p. 85. 



It is not necessary to repeat here what has just been said under Psammechinus, 

 regarding the type of this genus. Careful study of large series of specimens 

 from Bermuda, South Carolina, Florida, Yucatan, various West Indian islands, 

 and Brazil shows that the Bermudian form, originally described under the name 

 of atlanticus, which has recently been reinstated by Jackson (1912, Mem. Boston 

 Soc. Nat. Hist., VII, p. 121), can hardly be maintained as a valid species. 

 Typical specimens from Bermuda are strikingly different from Floridian and Caro- 

 linian specimens, while in both regions, the characteristic green and white West 

 Indian form seems to be unknown. We have specimens from Brazil however, 

 which are much like the Bermudian form, while many Bermudian specimens are 

 distinctly green. It seems clear that variegatus is a highly variable species, which 

 in Bermuda is developing into a very slender spined, deep purple form, while 

 along the continental coast it is becoming stout spined and deep pink. In the 

 Brazilian region, variation does not seem to have become fixed in any special line. 



