54 HAWAIIAN AND OTHER PACIFIC ECHINI. 



the Cape of Good Hope, in 56 fathoms, and identified by Doderlein as Pat- 

 tersoni, but which is undoubtedly distinct from that species, and may be appro- 

 priately called pUoinissa (=dark red); and S. eincta A. Ag. and CI., collected 

 by the "Albatross" in the northwestern Pacific, in 95-152 fathoms. (So 

 far as can be judged from de Meijere's brief description, the small Salenia 

 collected by the "Siboga" in the Sulu Archipelago, in 290 fathoms, and 

 referred by him to Pattersoni, is probably cincla.') These three living species 

 are all notable for their handsome coloration, the abactinal system being pret- 

 tily ornamented, and the primary spines conspicuously banded or spotted 

 with some shade of red. They may be distinguished from each other as 

 follows : 



Actinal system, .40-55 h. cL* ; primaries rather slender, thickness commonly 

 much less than 5 per cent of length ; no red-brown pigment on test or 

 secondaries. 

 Abactinal system, .60-.70 h. d., light colored with plates outlined in deep 



violet ; primaries with 3-5 broad bands of bright red Pattersoni. 



' Abactinal system, .55-.60 h. d., deep purplish ; primaries with 12-16 nar- 

 row bands of dull red eincta. 



Actinal system, .30-35 h. d. ; primaries rather stout, thickness often 4-5 per 

 cent of length ; test and secondaries with red-brown pigment ; abac- 

 tinal system about .55 h. d., very dark ; primaries with 9 broad, brown- 

 red spots on upper surface phoinissa. 



In addition to these differences, it is interesting to note that Pattersoni 

 has both tridentate and quadridentate pedicellarite, the latter with valves up 

 to 2 mm. long, while j^homissa apparently lacks quadridentate, and the valves 

 of the tridentate are seldom half a millimeter in length. In eincta neither 

 tridentate nor quadridentate pedicellariae have been found, and it would 

 seem that they are characteristically absent. In Doderlein's description of 

 the " Valdivia" specimen, he says there are 3 rows of secondary tubercles 

 in the ambulacra. It is impossible to tell from the illustrations given 

 whether this is really the case, or whether the " 3 " is not a misprint for 2. 

 If it is not a misprint, we have here another very important difference be- 

 tween phoinissa and Pattersoni, for even the largest specimens of the latter 

 have only 2 series of ambulacra! tubercles. 



1 There are two abbreviations used frequently in the following pages, h. d. and v. d. ; the former 

 refers to the horizontal, the latter to the vertical diameter of the test. 



