A. JE. Verrill — JVbrth American Ophiuroidea. 333 



Series III. 



In the following groups the oral shield is separated from the side 

 arm-plates by the adoral shields. 



Group H. — Ophiopora Ver., 1899a. Type, 0. Bartletti (Lym.). 

 Tentacle-pores all large and open. No tentacle-scales. 



Group I. — Ophiolimna Ver., 1899a. Type, 0. Bairdii (Lym.). 



Spine-crest of the side arm-plates distally situated and oblique. 

 Spines nearly smooth. 



Disk granulose and spinulose. Jaws more or less granulose. 



Group J, — Ophiopristis Ver., 1899a. Type, 0. hirsuta (Lym.). 



A row of distal oral papillae alongside of the large outer ora 

 tentacle-pore. Arm-spines partly flattened with serrulate edges. 

 (See p. 347.) 



Group K. — Ophiotreta Ver., 1899a, p. 40. Type, 0. Uneolata 

 (Lym.). 



One or two flat, distal oral papillae by the side of the large oral 

 tentacle-pore. Two or three tooth-papilla. Spines mostly terete, 

 but sometimes flattened and with serrulate edges. (See p. 328.) 



Group L. — Amphipsila Ver,, 1899a, p. 55. Type, A. macidata Ver. 



Oral papillae form a simple row. Two or three tooth-papillae in 

 the marginal series. Disk-scales and radial shields naked, small. 

 Tentacle-scale slender, spiniform or palmate. Arm-spines serrulate 

 flattened, hollow. (See p. 348.) 



OpTiiocopa Lym. also belongs in this series. 



Ophiacantha, sens. ext. 



Artificial groups of species from the West Indian region and from 

 the East Coast of JSTorth America, arranged accord- 

 ing to various special characters. 



All the species appear in groups I and II. In these two groups 

 all the northern species are indicated by an asterisk prefixed. These 

 groups are not intended as natural sections of the genus, though they 



Trans. Conn. Acad., Vol. X. October, 1899. 



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