302 HAT^AHAX AXD OTHER PACIFIC ECHINI. 



LAMPRECHrKTJS. 



Doderlein, 1905. Zool. Anz., XX'V'in. p. 622. 

 TA-pe-species, Lamprechinus tiitidus Doderlein, 1905. 1. c. 



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

 Judging from Doderlein's description and figures it must be ven* near Orwhinus, 

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

 quite trivial. The genus is monotjpic and since the only specimens were tAken 

 off South Africa in 276 fathoms, at the same place where OrechinMS m/moHfii 

 was taken, its supposed characters may represent only indi\idual divcrshj' <rf 

 Orechinus. 



Pri onechixtjs. 



A. Agassz, 1S79. Proc. Amer. Acad., XR', p. 202. 

 TA-pe-species, Prionschinus sagiitigcr A. Agassiz, 1S79, 1. c 



Of all the genera of Temnopleuridae this is not only the least wiell <ietoed> 

 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 comparati\-e study, 

 Te5t-sculpTuring reaches its lowe^^t limit in this genus; in SiWie of the sixvies, 

 it is quite wanting and m others it is chiefly on the abactinal s\-stom. What 

 characters are really of specific importance, it is hard to detormine for st> little 

 of their significance is kno\^^l. The position of the genital ix-jre on the plate 

 is used as a specific character but it may be only sexual, and the pn^nioe 

 or absence of tube-feet on the buccal plates may be a matter of age. .\nd 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 lx»st distinguisluxl by the 

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

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

 certain what its true relationships are. It seems quite pn^bable. as Or. Morton- 

 sen luis pointed out with rather undue emphiisis ("Ingolf" Koh.. pt. I, p. S2), 

 that more than one species was includeil under the name Prioncchinus $affiUi(ffr 

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

 on Plate \V were not all taken from the s;ime specimen. It s^hmus Inv^^t to 

 follow Mortensen and de Meijere in taking tlie sptvimen from "Challenger" 

 Station 218 ^shown in "Challenger" Rept.. PI. \T', fig. 11) jis the (y|KMif the 



