^^2 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 8 



Encope irregularis^^, new species 



Plate 5S, Figs. 52-53 



Test stout and more or less irregular in shape. Of all the specimens at 

 hand, only one, a relatively j'oung one, is symmetrical. The one selected 

 for holot}'pe is here used as basis of description but no other specimen is 

 like it in all details. Length 1 12 mm, width 1 16 mm, height 13 mm. Apex 

 of test only 25 mm back of anterior margin, from which point the test 

 slopes gradually to posterior lunule and thence rapidly to margin. Un- 

 paired petal and anterior pair of about equal length, 35 mm and width 

 18-20 mm; poriferous zones, 4 mm across with some 20 verj'^ small 

 tubercles in each series; interporiferous area 10 mm wide with very fine 

 tubcrculation; tips of petal open, only 4 mm from anterior lunule, which 

 is only about 5 mm from margin and is 9 x 4 mm in size. Anterior paired 

 lunules about 40 mm from anterior end of test; each is about 8 mm long 

 by 3 mm wide ; the right hand one is closed by about 7 mm of test but the 

 left hand one has never closed, though the lower margin has bent forward 

 as though to do its part. Posterior petals somewhat longer than anterior 

 but essentially similar. Interambulacral lunule small, only 8 mm long by 

 2.5 mm wide; its posterior end is 15 mm from rear end of test and its 

 anterior end is well within (3 or 4 mm) the line joining the tips of the 

 posterior petals. Posterior lunules short and narrow, 10x2 mm, only 

 about 7 mm from test margin. Lower surface flat or barely concave, the 

 pattern formed by the ambulacra unusually distinct and striking. Spines 

 of abactinal surface relatively short and crowded, the tips swollen and flat 

 for the most part but around the lunules long, flat and pointed or truncate. 

 G)lor of abactinal surface very dark, approximately fuscous or fuscous 

 black of Ridgway ; the marginal fringe of short spines, the tips of the spines 

 around the lunules and the whole lower surface are brown of some shade, 

 usually dark and often with a purple cast. There is considerable diversity 

 in the shades of color, so that no two individuals are exactly alike. In one 

 large specimen there is a distinct hint of deep green, while in several dark 

 violet is indicated. In general one may say the color is dark and dull. 



Besides the holot^'pe there are 21 specimens of this Encope, but 4 of 

 these are so small (less than 25 mm) their identity is based wholly on the 

 fact that they are from the coast of Costa Rica. The remaining 17 are 

 remarkable for their asymmetry. The smallest, 85 mm in length, shows no 



^^ trrr^ularis=\ackins regularity in form or character, in reference to the fact 

 tuat nearly all the specimens are imperfectly formed at least in some detail. 



