SHALLOW-WATER STARFISHES 65 



cc. Longitudinal rows of spines more than five, not very obvious, due to 

 crowding; spines appear as if in quincunx. 



f. Dorsal spines long, slender, slightly grooved. Adambulacral spines 



slender, orals longer. Major pedicellariae large, lanceolate, acute, 

 dentate at tip. 

 O. kcchleri Lor., p. 175. Vancouver I. 

 bb. Dorsal spines in three rows, long, not fluted ; ossicles openly reticulated, 

 leaving large papular areas ; spines of two inferomarginal rows and 

 peractinal row slender, elongated, tapered ; adambulacral spines 

 rather slender, tapered or slightly flattened. Major pedicellariae 

 large. 

 O. dawsoni Ver., nov., p. 175. Brit. Columbia, 

 aa. Rays six, rounded and elongated. Dorsal spines large, in three or five 

 rows, with smaller ones interpolated, all with a thick fleshy sheath 

 (in alcohol) bearing a large wreath of minor pedicellaris at about 

 mid-height or above. Both marginal rows of spines are regular 

 and mostly simple. A regular peractinal row of spines and in 

 mature specimens a short subactinal row proximally. 

 O. merriami Ver., nov., p. 177. Alaska. 

 LL. Peractinal spines generally lacking; the ossicles are rudimentary or small; 

 inferomarginals with two rows of spines. 

 Subgenus Slylasterias Ver., nov., p. 179. 



g. Dorsal spines mostly in three longitudinal rows, often with some scattered 



intermediate ones. 



h. Minor pedicellariae remarkably large and unguiculate, about half as long 

 as major ones, forming large, loose, basal circumspinal wreaths. 

 Larger major pedicellariae often nearly as stout as the spines. 



i. Spines long, inferomarginals in two rows and, like the outer adambulacral 

 spines, often notably flattened and spatulate or gouge-shaped. Outer 

 adambulacral spines are the larger; papular areas large; peractinal 

 plates very small. 

 O. forreri (Lor.), p. 179. California. 



ii. Adambulacral plates and spines crowded; spines slender. Minor pedicel- 

 lariae remarkably large and abundant; dorsal ones in large groups 

 on the dermis and around bases of spines ; dorso-lateral ossicles 

 rather slender, openly reticulated; papular areas large; major pedi- 

 cellariae very stout. 

 Subspecies forcipfttata Ver., p. 180. British Columbia. 



hh. Minor pedicellariae not notably large ; they form large, dense, basal circum- 

 spinal wreaths ; inferomarginal and adambulacral spines flattened, 

 not notably spatulate nor strongly gouge-shaped. Dorsal spines 

 well spaced, elongated, tapered, not fluted ; alternate superomarginal 

 plates mostly spineless. 

 O. gonolena Ver., nov., p. 184. S. California to Gulf of Calif. 



gg. Dorsal spines in more than three rows ; rays slender, terete. 



Dorsal spines in about five rows, long, nearly uniform, tapered; 

 papular areas large; rays slender; inferomarginals tapered, obtuse; 

 adambulacrals small, slender, outer ones a little larger and longer, 

 slightly clavate. Major pedicellariae large, denticulate. 



