200 



BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



fornian specimens. Some specimens have mostly four furrow spines to a plate, 

 others three, while still others both numbers; four is the usual number for typical, 

 large examples, though some have three, and less conunonly five. There is also 

 variation in the number of granules to the abactinal paxilliform plates, especially 

 of the radial areas. For instance, a specimen with R = 42 mm., on the midradial 

 parapaxilliB, at base of ray, has about eighteen to twenty peripheral granules and 

 fifteen to seventeen central. Another specimen with R = 59 mm. — consequently 

 larger — has only fourteen or fifteen peripheral and five. to ten central granules. 

 The granules vary a little in size, being slenderer and more spiniform in the 

 peripheral series in some examples, crowtled and more granuliform in others. 



The rays vary in thickness, especially distally, according to whether one, two, 

 or three rows of plates attain the terminal plate. In some examples the actinal 

 intermediate pediccllariije are higher than the abactinal, and have a shorter base 

 line; in others the}' are scarcely different from the abactinal. 



A remarkable variation is presented by one specimen from the type-locality, 

 Puget Sound. In this example there are numerous small secondary abactmal 

 parapaxillffi on the median radial areas (proximally). Practically all the adam- 

 bulacrals have five furrow spinelets and the first actinal series is set oblicjuely. 

 There is one six-rayed and one four-rayed specimen in the collection. 



Young. — The smallest specimen (station 2934) has R = 8 mm.; marginal plates, 

 eight; papulse restricted to radial areas; tabula low or absent; granules, two or 

 three central and about eight peripheral on proximal radial region; two or three 

 abactinal pcdicellariie; three furrow spinelets; one or two actinal pedicellaria^. 



Types. — In Coll. Suckley (Puget Sound) , and in U. S. National Museum (Cali- 

 fornia), Cat. No. 1977. 



Type-locality. — Puget Sound, Washington, or San Francisco, CaUfornia. 



Distribution. — From the Alaskan Peninsula (Chignik Baj') south to northern 

 Lower California, in shallow water (9 to IGO fathoms). 



Specimens examined. — About two hundred and tliirty-oiie specimens from the 

 following stations: 



Specimens of Mcdiastcr xqualis examined. 



Depth. 



Nature of bottom. 



rociis 



roclis and shells 



....do 



rocky 



broken shells, sand 



sand, mud 



fine gray sand 



gray sand, broken shells, 

 fine gray sand 



do 



gray sand 



do 



fine gray sand 



gray sand, broken shells 



rocky 



gray sand, broken shells 



U. S. Nat. Mus. 



