NO. 4 ZIESENHENNE: NEW EASTERN PACIFIC SEA STARS 213 



aster volsellatus (Sladen) and Coronostcr halicepus Fisher, Philippine 

 Islands, and Coronaster cclipes Fisher, Hawaiian Islands. 



jMarchenus, having 2 adanibulacral spines, cannot be confused with 

 volsellatus. It differs from halicepus as well as briareus of the West Indies 

 in lacking broad, unguiculate, hand-shaped, straight pedicellariae. In C. 

 eclipes (described from a single ray) these unguiculate pedicellariae are 

 also lacking; and the lanceolate type, so characteristic of marchenus, is 

 found only on the furrow face of the adambulacrals. But the furrow 

 pedicellariae of marchenus are similar to those of volsellatus and quite un- 

 like the smaller more triangular ones of eclipes (see Fisher, Sea Stars 

 Tropical Central Pacific, Bishop Museum Bulletin No. 27, 1925, p. 78, 

 fig. 9 d, e, f). The crossed pedicellariae are essentially the same as those 

 of volsellatus, with a similar wide range in size. Characteristic of mar- 

 chenus are the fissiparous habit and the presence of upward of 5 madre- 

 porites, features which have not been reported for the other species. 



The name marchenus has reference to Marchena Island, on whose 

 rough lava reefs this species was taken in abundance. 



