Clark — Four New Echinoderms from the West Indies. 67 



terminal portion longer than broad; after the first two or three the 

 brachials develop overlapping and finely spinous distal edges which be- 

 come prominent after the sixth or eighth, though their development is 

 never very great; they are plainly evident even in the attenuated termi- 

 nal portion of the arm. Syzygies occur between the third and fourth 

 brachials (the second and third in arms arising from a II Br axillary), 

 again between the sixth and seventh to ninth and tenth, and subsequently 

 at intervals of four oblique muscular articulations. 



The mouth and anal tube are about equidistant from the center of the 

 disk ; the mouth is radial ; the disk is entirely covered with a pavement 

 of very small plates, with a few larger ones which rise above the general 

 surface scattered about the interpal mar areas; in the lateral interbrachial 

 regions of the disk the mass of small plates tends to divide into two col- 

 umns of large plates based upon a single plate in the interradial angle. 



P D is 12 mm. long, stout basally but tapering rather rapidly and slender 

 and flagellate in the distal two-thirds, with nearly forty segments of which 

 the first is about twice as broad as long, the second is nearly as long as 

 broad, the third is of about the same proportions, and the following 

 gradually increase in length, becoming about as long as broad after the 

 seventh and slightly longer than broad in the terminal portion ; the seg- 

 ments in the proximal third have very prominently everted and spinous 

 distal ends; the comb consists of thirteen teeth, the terminal two or three 

 more or less obsolete ; the teeth are slightly longer than broad basally, 

 about as long as the lateral diameter of the segment which bears them, 

 rounded, well separated, and beset with small marginal spines; except 

 for the first two or three all the teeth are double, the segments bearing 

 another similar, but smaller, tooth on the opposide side; P x 7 mm. long, 

 much more slender than P D though similar to it, and with a similar 

 comb; P 3 is small, slender and weak, 3 mm. long with about fifteen 

 segments, bearing a more or less imperfect comb distally; P 4 and the 

 following pinnules resemble P 3 , but are without combs ; on arms arising 

 directly from a I Br axillary P a resembles P D as described, P 2 resembles 

 P lt etc.; the distal pinnules are 9 mm. long, very slender, with about 

 twenty segments of which the first is short, the second half again as long 

 as broad, the following rapidly becoming elongate, and about three times 

 as long as broad ; the segments all have very strongly overlapping and 

 spinous distal ends, as do the segments of all the pinnules except in the 

 distal portion of the first one or two. 



Color in alcohol white, yellowish white, or violet, the cirri and pinnules 

 dark purple with the ends of the segments white, in sharp contrast. 



Type.— Cat. No. 25,458 U. S. N. M., from "Albatross" Station 2146, 

 Caribbean Sea, in 34 fathoms. 



II. STARFISH. 

 Plinthaster productus new species. 

 Five arms; R=27 mm. ; r=12 mm. ; R:r=2.25:l; superomarginals 10 

 or 11, of which the distal 8 are united interiorly to form the ray. 

 General form pentagonal, with slightly incurved sides, the angles of the 



