280 HAWAIIAN AND OTHER PACIFIC ECHINI. 



small, in nearly vertical arcs of three pairs. The ambulacra are nearly as wide as 

 the interambulacra. The actinostome (PI. 97, fig. 2} is relatively large but the 

 gill-cuts are very shallow and inconspicuous. The buccal membrane is thin 

 and perfectly naked save for the small primordial ambulacral plates. The 

 primary spines are short, rather stout, and not very acute. 



The pedicellariae are common but very small. The globiferous are remarkable 

 for the very short, hook-like blade of the valves (Plate 93, fig. 1) which are only 

 about .15 mm. long, with the base about .10 mm. wide. The ophicephalous 

 have somewhat larger valves, about .20 mm. in length, with an additional .03 to 

 .05 for the loop; they are slightly constricted at the base of the blade. No 

 tridentate nor triphyllous pedicellariae were found, nor were sphaeridia or calcareous 

 spicules seen. 



The test is almost white with about a dozen irregularly scattered blotches 

 of dull purple at and above the ambitus. The spines are white but the primaries 

 are encircled at the middle by a broad, poorly defined band of rose-violet (K. & 

 V. 597). 



The specimen upon which this new species is based was taken by the "Siboga" 

 in the Sulu Archipelago in 7-8 fathoms. (Station 109.) It was received by 

 the Museum of Comparative Zoology from the Amsterdam Museum, through 

 the kindness of Dr. Weber in 1907, bearing the label " Psammechinus verruculatus 

 L. Agass." In the report on the "Siboga" Echini, (p. 89), de Meijere records 

 nine specimens of "Psammechinus verruculatus Liitken" from Station 109 and 

 doubtless this specimen is one of them. But it does not seem possible to regard 

 it as verruculatus for in specimens of that species which are as small as, or smaller 

 than, stictus, the buccal membrane is fully plated. Moreover the coloration 

 is very different from any specimens of verruculatus, which I have, seen, and the 

 globiferous pedicellariae are different, resembling those of "Echinus darnleyensis 1 ' 

 as figured by Mortensen ("Ingolf" Ech., pt. 1, PI. 21, fig. 36) very closely. 

 Indeed there can be little doubt that darnleyensis is the nearest ally of stictus, 

 the difference in coloration being the most obvious distinction. Larger series 

 of the two species may show that they are identical. 



