1918 Bush: on Echinoderms 25 



Ic. Evasterias troschelii subnodosa Verrill. 



Dorsal skeleton very firm ; dorsal spines clustered in nodular groups, 

 with large central capitate spines and smaller outer ones, often a median 

 row ; spines large, numerous. — Numerous, in deep water and along tide 

 line. 



2. Evasterias acanthostoma Verrill. 



Forms large ; rays long, acute at tips. Dorsal spines numerous, small, 

 almost equal, columnar, club-like or tapering, tips rough, not arranged 

 in evident net-work nor longitudinal rows but often in short transverse 

 rows ; marginal and interactinal spines from 5 to 6 mostly double and 

 crowded rows with about 8 or 10 in each transverse row; pedicellariae 

 numerous; major pedicellariae small. Adambulacral spines elongated, 2 

 to a plate. — Not numerous, in deep water. 



Genus Asterias 



Size usually large; rays 5, rarely 6. Dorsal ossicles and spines 

 variously arranged, most often openly reticulate; dorso-lateral plates 

 rather small, usually reticulate or irregularly arranged, united by their 

 lobes or by smaller transverse ossicles ; upper marginal spines form a 

 distinct row with a channel between it and the lower marginal row ; inter- 

 actinal spines usually form 1 long row like the lower marginals and 1 or 2 

 short proximal rows, but these may be rudimentary or lacking, specially in 

 the young, so that only 2 rows of ventrals are present; lower marginals 

 and actinals may stand 2 or more to a plate, making 4 or 5 rows; major 

 pedicellariae usually small, ovate or lanceolate, sometimes unguiculate. 

 Larvae free swimming. Genital pores dorsal. 



1. Asterias victoriana Verrill. 



Rays 5, rather long, rounded. Dorsal spines few, short, capitate, 

 forming a median row, a few irregularly scattered ones of similar size and 

 form on each side; 2 marginal and 2 interactinal rows regular and mostly 

 simple, their spines short, stout, blunt; ambulacral spines 1 or 2 to a plate. 

 — Very scarce, in deep water. 



Genus Orthasterias 



Size usually large ; rays 5 ; disk small. Dorsal skeletal jilates lobed, 

 arranged in rather evident longitudinal rows ; dorsal spines very large, 

 1 or rarely 2 to a plate, forming 3 to 5 or more rather evident rows, smaller 

 spines may occur irregularly between the rows; marginal spines more like 

 dorsals and forming regular rows; actinal spines 1 or 2 rows or lacking; 

 major pedicellariae large, 2 or more kinds, larger ones toothed; minor 

 pedicellariae numerous ; adambulacrals 2 to a plate or alternating 1 and 2. 



