SHALLOW-WATER STARFISHES 3OI 



the larger ones, and may not have the central spine. Plates some- 

 times partially obscured by a thin integument. 



Actinal plates rather large, angular, closely tesselated, arranged in 

 rows parallel with the adambulacrals. They are surrounded by a 

 row of coarse granules and bear either a large and wide bivalved 

 pedicellaria, like those of the dorsal plates, or else one or more 

 central tubercles. Sometimes nearly all of them bear large pedi- 

 cellarias. 



Adambulacral plates large, but smaller than the interactinals, 

 squarish, bearing a marginal row of large granules, or short, blunt 

 spinules, one, or sometimes two, stout, central spines, and a longi- 

 tudinal furrow-series of few, usually two or three, smaller divergent 

 spines. (See pi. xlviii, fig. 5.) 



Oral or dentary plates large, bearing a marginal row of rather 

 strong oral spines, besides two rows of shorter epioral ones on the 

 actinal surface. (See pi. xlviii, fig. 2.) 



Median dorsal pore large, surrounded by papillae. (See pi. xlviii, 

 fig. 4.) Tube- feet stout, with large suckers. 



Madreporic plate rather small, with few coarse gyri. (PI. xlix, 

 fig. 6.) Papulje small, isolated, in the angles between the abactinal 

 plates. (See pi. xlviii, figs. 1-4.) 



Besides the following species, Professor Fisher has described three 

 deep-water species from the North Pacific. Neither of them has 

 been recorded from within the limits of this report. 



The North Atlantic and Arctic species, H. phrygiana, common on 

 the coast of New England, in 50 to 200 fathoms, has not yet been 

 found on the Pacific side. (See pi. xlvii ; pi. xlviii, figs. 1-5; pi. 

 XLIX, fig. 6, for details.) 



HIPPASTERIA SPINOSA VerriU. 

 Plate L, figures 4-4^; plate xcviii, figure i (type). 



Hippasteria spinosa V'ersill. Amer. Journ. Sci., xxvui, p. 63, July, 1909. 

 Fisher, op. cit., 19116, p. 224, pi. xui, figs. 1-3; pi. xuii, figs, i, 2; pi. lx, 

 fig- 4- 



Arms rather longer than in the Atlantic species. Upper surface 

 thickly covered with rather slender, tapered, acute, unequal spines, 

 nearly every plate bearing a single spine ; those that do not have a 

 spine carry a large central pedicellaria, about equal in diameter to the 

 corresponding spine, but varying in size, like the spines, according 

 to the size of the plate. The spines and pedicellariae are surrounded 

 at the base by one or more circles of granules borne on the plates 



