Verrill, JSfotes on Radiata. 313 



longer ones, not clavate ; lower surface with three kinds, the median 

 region of each interambulacrum with crowded spines, which are longer 

 and stouter than those of other parts and slightly enlarged toward 

 the ends; on the median area of the ambulaci-a, in line with the 

 lunules, the spines are similar in form, but much fewer and smaller ; 

 between these two kinds the surface is covered with very small crowded, 

 clavate spines, similar to those of the upper surface, but less enlarged 

 at the tips. Color, when dried, dull greenish brown. 



Mellita Pacifica VerriU, sp. nov. 



A depressed, subcircular species, with six perforations ; allied to M 

 hexapora, but having a large, round posterior, and small, narrow 

 ambulacral perforations ; spines of the upper side short and crowded. 



Length, not including spines, 2*2 inches; greatest breadth 2-3; 

 height "25; from center to end of anterior ambulacral ray -58; to 

 end of anterior-lateral '55 ; of posterior-lateral '61 ; width of anterior 

 ambulacral ray '27; its central area MS; of anterior-lateral -25; its 

 central area "12; of posterior lateral -25; its central area -10; from 

 center to anterior perforation -83 ; to anterior-lateral 'SI ; to posterior- 

 lateral -8 ; to posterior -4 ; length of latter -25 ; its width -2 ; mouth 

 to anal opening '25; length of marginal spines "IS. 



Tlie outline is nearly circular ; broadest a little behind the center, 

 where the outer edges of the posterior-lateral interambulacra are 

 somewhat prominent beyond the rest of the outline ; center of abac- 

 tinal rosette a little behind the middle ; edges thin. The five ambu- 

 lacral perforations are small and narrow, elliptical ; the posterior one 

 is large and broad oval ; its inner half within the ends of the posterior 

 ambulacral rays. The ambulacral rays are elongated-oval ; the poste- 

 rior pair longest; the anterior-lateral pair shortest; each with a well, 

 marked naked median line. Plates of the upper siirface relatively 

 more numerous than in M. hexapora^ and narrower in the direction of 

 the radii ; four ambulacral plates intervening between the perforations 

 and the ends of the rays, while in M. hexapora of similar size tliere 

 are but two. Spines of the upper surface close and short, slender at 

 base, with greatly enlarged, rounded tips; those of the raaroinal 

 fringe long, tapering, often acute ; those of the median regions of the 

 interambulacra are similar in form to those of the margin, but much 

 more slender and delicate; those of the areas enclosed by the primary 

 radiating grooves are very small and slender, not clavate. 



Color, deep green when dried. 



Zorritos, Peru, at low-water mark, — F, H. Bradley, 



