302 HAWAIIAN AND OTHER PACIFIC ECHINI. 



LAMPRECHINUS. 



Doderlein, 1905. Zool. Anz., XXVIII, p. 622. 

 Type-species, Lamprechinus nitidus Doderlein, 1905, 1. c. 



Not having seen a specimen of this genus, I am in doubt as to its validity. 

 Judging from Doderlein's description and figures it must be very near Orechinus, 

 and so far as can be determined the points which separate it from that genus are 

 quite trivial. The genus is monotypic and since the only specimens were taken 

 off South Africa in 276 fathoms, at the same place where Orechinus monolini 

 was taken, its supposed characters may represent only individual diversity of 

 Orechinus. 



PRIONECHINUS. 



A. Agassiz, 1879. Proc. Araer. Acad., XIV, p. 202. 

 Type-species, Prionechinus sagittiger A. Agassiz, 1879, 1. c. 



Of all the genera of Temnopleuridae this is not only the least well defined, 

 but it is also the one within which specific limits are hardest to draw. There 

 are several reasons for this, particularly the small size, the occurrence only in 

 deep water and the lack of sufficient material for careful comparative study. 

 Test-sculpturing reaches its lowest limit in this genus; in some of the species, 

 it is quite wanting and in others it is chiefly on the abactinal system. What 

 characters are really of specific importance, it is hard to determine for so little 

 of their significance is known. The position of the genital pore on the plate 

 is used as a specific character but it may be only sexual, and the presence 

 or absence of tube-feet on the buccal plates may be a matter of age. And the 

 question whether color has any significance is also of importance. The result 

 of my efforts to distinguish the described species follows but it is doubtful if all 

 these species are valid, or if valid whether they are best distinguished by the 

 characters used. It is probable that de Meijere is correct in assigning Cottaldia 

 Forbesiana A. Ag. to this genus, although lack of material makes it very un- 

 certain what its true relationships are. It seems quite probable, as Dr. Morten- 

 sen has pointed out with rather undue emphasis ("Ingolf" Ech., pt. 1, p. 82), 

 that more than one species was included under the name Prionechinus sagittiger 

 in the report on the "Challenger" Echini and that unfortunately the drawings 

 on Plate VI a were not all taken from the same specimen. It seems best to 

 follow Mortensen and de Meijere in taking the specimen from "Challenger" 

 Station 218 (shown in "Challenger" Rept., PI. VI a , fig. 11) as the type of the 



