Clark — Three Starfish and One Brittle-star from Chile. 153 



shorter spines ; rarely there is an enlarged spine on the distal portion of 

 the actinal surface of the plate. 



The mouth plates have twelve short spines along the median border 

 which decrease slowly in length distally; on the furrow margin there are 

 four or rive long spines continuing into a similar series of from five to 

 seven more slender spines similar to those on the adambulacrals, one or 

 two of which stand on the edge bordering the first adambulacral ; the 

 most proximal of these arises between the most distal spine of the furrow 

 series and the furrow. A few additional spines similar to those in the 

 central rows occur on the free surface of the plates. 



The color in alcohol is grayish white. 



Type— Cat. No. 36,949, U. S. N. M., from "Albatross" Station 2788, 

 off the coast of Chile, in i050 fathoms. 



Family LUIDIID^ Verrill. 

 Luidia porteri, new species. 



Five arms; R=98 mm.; r=ll mm.; R:r=8.9:l ; width of arms at base 

 12 mm.; superomarginal paxillse 70. 



Arms long and unusually narrow, slowly and regularly tapering from 

 the base to the tip ; upper surface flat, not especially depressed, the first 

 row of paxillse beyond the superomarginals defining the border of the 

 dorsal surface. 



The paxillse are exceedingly delicate, with a short central spinule and 

 several long and very slender radial spinules ; they are everywhere in 

 contact with their neighbors through the long radial spinules. 



The superomarginal paxillse correspond to the inferomarginals ; they 

 are more or less oval in shape, mostly about twice as long as wide, and 

 carry about twenty long radial spinules, some of which are almost hair- 

 like, and from five to ten somewhat shorter spinules on the summit; at 

 the base of the arm they bear from one to five (usually from one to three) 

 pedicellarise of different sizes, but after the middle of the arm pedicellarise 

 become very rare. 



Within the superomarginal paxillse is a row of much smaller paxillse, 

 five of which correspond to three superomarginals ; these have about ten 

 long radial spinules and from three to five shorter central ones, and are 

 approximately circular in outline. Within this row the paxillse decrease 

 almost imperceptibly in size and in regularity of arrangement to the mid- 

 line of the ray, where they have most commonly eight slender radial 

 spinules, and a single short median spinule. 



Occasional paxillae in the center of the disk and in the central portion 

 of the ray bear prominent granuliform pedicellarise, but these are not 

 very abundant, and are almost entirely absent from the distal half of the 

 arms. 



In the actinal half of the interbrachial arc and on the adjacent arm 

 bases pedicellarise are extraordinarily abundant, occurring on all the 

 paxillse, sometimes as many as five on one paxilla. 



