72 ' VERRILL 



PISASTER OCHRACEUS, Van NODIFERUS Verrill, nov. 



Plate LVi, figures 3, 2('. 



This name is proposed for that variety of this species which has 

 the dorsal spines collected into large detached groups. 



The form is the same as in the typical reticulated variety, and 

 specimens occur of all sizes from two inches up to a foot or more in 

 diameter. 



A strongly characterized small specimen from Monterey has the 

 radii 16 mm, and 52 mm, ; ratio, i : 3.25, The dorsal ossicles are 

 reticulate, but so many are without spines that the latter show no 

 regular reticulate pattern. The Geological Survey of Canada sent me 

 several specimens with the nodular character even more prominent. 



The dorsal spines are all capitate and somewhat unequal; they 

 form a conspicuous pentagon with a central cluster on the disk and 

 five prominent median radial rows proximally. Between the median 

 and superomarginal rows there are ten to twelve large irregularly 

 placed and very prominent clusters of capitate spines, with about 

 five to eight spines in each group. 



The superomarginal spines form a simple regular row in the type; 

 they are about equal in size to the dorsal spines, but more conical. 

 The ventral and adambulacral spines and the pedicellarise are like 

 those of the typical form, A very young specimen, also from Mon- 

 terey, has the radii 8 mm. and 24 mm, ; ratio, i : 3, 



This small one agrees with the preceding in all essential characters, 

 but the spines are correspondingly smaller and there are but two 

 distinct rows of interactinal spines. The pentagon on the disk is well 

 marked. 



This variety occurs commonly from Monterey, Calif., north to 

 Sitka, Alaska. It is the predominating variety on some parts of the 

 coast of British Columbia, on rocks at low tide. 



Six-rayed specimens are not very rare. 



HYBRIDS ? 



There are indications that this species may hybridize with 

 L. epichlora and with others, for where they live associated, as at 

 Sitka, specimens occur that seem to belong to Leptasterias epichlora, 

 but have some of the characters of ochraceus, in a greater or less 

 degree. 



One young L. epichlora from Wrangel, Alaska (var. suhnodu- 

 losa), has only five rays, and the dorsal spines are more strongly 

 acervate and much larger than usual, giving it a close superficial 



