296 HAWAIIAN AND OTHER PACIFIC ECHINI. 



the "Siboga" in the Sulu Archipelago in 153 fnas. Very hkely this species 

 will prove to be intertropical in its distribution in water 100-500 fathoms deep. 



The specimens collected by the "Albatross" were taken at the following 

 places: — 



Station 3859. Off Mokuhooniki Islet, Pailolo Channel, Hawaiian Islands. 

 Bott. temp. 60.5°-60.2°. 138-140 fathoms. Fne. s., m. 



Station 3863. Off Mokuhooniki Islet, Pailolo Channel, H. I. Bott. temp. 

 6r-60°. 127-154 fathoms. Brk. co., crs. g., r. 



Station 3892. Off Mokapu Islet, north coast of Molokai, H. I. Bott. 

 temp. 42.5°. 328-414 fathoms. Fne. g. s. 



Station 4045. Off Kawaihae Light, west coast of Hawaii, H. I. Bott. 

 temp. 49°. 147-198 fathoms. Co. s., for. 



Bathymetrical range, 127-414 fathoms. Extremes of temperature. 61°- 

 42.5°. 



Five specimens. 



Hypsiechinus. 



Mortensen, 1903. "Ingolf" Ech., pt. 1, p. 81. 

 Type-species, Hypsiechinus coronalus Mortensen, 1903, 1. c. 



Mortensen (1904, Siam Ech., p. 57) holds that this genus is "the most primi- 

 tive of all the Temnopleuridse " and refers to the globiferous pedicellariae and cal- 

 careous spicules as evidence of the fact. There may be suggested as confirmative 

 facts, the structure of the abactinal system of the male, the plating of the buccal 

 membrane, the rudimentary condition of the auricles and the paucity of spines. 

 It is interesting to note that Trigonocidaris is only a little more specialized, the 

 auricles being a little higher, the valves of the globiferous pedicellariae having 

 only a single lateral tooth on the left side and the spicules being bihamate. 



Hypsiechinus is monotypic and is known only from deep water (450-799 

 fathoms) southwest and west of Iceland. 



Genocidaris. 



A. Agju-'siz, 1869. Hull. M. C. Z., I, p. 262. 

 Type-species, Genocidaris maculata A. .\gassiz, 1869, 1. c. 



The discovery of additional species of this genus, agreeing in certain int-erest- 

 ing details with the type species, seems to confirm the view of Pomel and Mor- 

 tensen that the generic name originally bestowed on the West Indian specimens 

 had better be retained. The exceptionally largo suranal plate, which is no 



