SHALLOW- WATER STARFISHES 217 



VARIATIONS. 



This species varies considerably in the proportions of the rays 

 and disk, some specimens having very long and slender rays, with a 

 small disk, while others have the rays shorter and more robust, 1 

 much as in H. sanguinolenta. There is, also, considerable variation 

 in size and form of the dorsal ossicles, some of the specimens almost 

 lacking the peculiar curved forms, characteristic of most. The 

 dorsal spinules, always numerous, vary in size, so that the degree to 

 which they are crowded is variable. Commonly they are obtuse, or 

 clavate, but often they are acute, or have thorny or spiculose tips. 

 The number and size of the adambulacral spines are also variable. 

 But the species is usually easily recognized. 



Six-rayed specimens occur rarely on the California coast. 



Professor Fisher (op. cit, 19116, p. 283) mentions a dwarf lit- 

 toral variety found at Monterey, California, which carried clusters of 

 orange-colored eggs in January. The disk was arched, making the 

 oral region concave, as usual in this genus when eggs or young are 

 carried by the mother. 



The following eight varieties, from California to Sitka, are not 

 regarded as subspecies by me, but rather as local varieties. 



HENRICIA LEVIUSCULA, Var. LEVIUSCULA (Stimpson). 

 Plate xu, figure 5 ; plate xni, figures I, 2. 



The specimen in the U. S. National Museum, supposed to be 

 Stimpson's type, is a small, slender-rayed specimen in rather poor 

 preservation. 



It belongs to the common variety having rather large, well-rounded 

 dorsal pseudopaxillae, pretty close together, x and with small papular 

 areas. The paxillary spinules are very short, even, and numerous. 



The two rows of marginals and the interactinal row of plates are 

 very distinct and pretty regular. 



The inferomarginals are the larger and are squarish. The adam- 

 bulacral spines are rather numerous ; the inner two to four are the 

 larger. 



l Prof. H. L. Clark (op. cit, p. 327, 1901) proposed varietal names based only 

 on the relative length of the rays and size of the disk. The stouter- and 

 shorter- rayed form (radii about i : 2-3.5) he called var. crassa; the longer- 

 rayed form (radii about 1:5-6), var. attenuata. But as all grades of inter- 

 mediate forms occur, these variations cannot be regarded as of much 

 significance. Several other species of the genus, if not all, vary in the same 

 manner. 



