216 BULLETIN "e. UNITED STATES NATIONAL MUSEUM. 



5 mm. from tlic raar<^iunl plates. The tabula which hoar these are nearly bare, 

 except for the peripheral and a few additional <z;ramdes. Usually the pedicellariaa 

 have special depressions into which the jaws fit when open. 



A specimen from station 4228 has furrow spinelets with thick spatulate tips so 

 that the spinelets taper toward the base. Two very thick, short, stubby spinelets 

 stand in the first actinal row. A comparison of Sladen's figure (pi. 49, fig. 4) with 

 those hero published will demonstrate better than a description the range of varia- 

 tion of the adambulacral armature. 



Young. — Two small specimens from station .322.3. The smaller has R = 1 .5 mm. ; 

 r=10 mm. Form arcuate pentagonal; marginals with conspicuous bare spot; 

 tabula of midradial series with two to six central and nine to eleven peripheral 

 granules which are more flat-topped than in adults. Primary basal plates large 

 conspicuous with a central bare spot. Furrow spinelets three or four, truncate or 

 round-tipped, prismatic or four-sided; two or three compressed spinelets or gran- 

 ules in first actinal series, three to five granules in outer part of plate. Mouth 

 plates with nine or ten marginal spinelets. 



Anatomical notes. — Intestinal coeca very large. There is a small central por- 

 tion, from which radiate four narrow thin-walled tubes. These each divide into 

 two distal thin-walled pear-shaped sacs, which resemble Polian vesicles. In two 

 interradii, these sacs reach as far as the marginal plates, or as far along each radius 

 as the hepatic coeca. Gonads very small, in two tufts on either side of interradial 

 septum and about one-third distance from margin to center. Polian vesicle in 

 four interradii; lacking in that of the niadreporic canal. Dorsal muscles weak; 

 arranged as in japonicAis, but much less conspicuous. Stomach with strong 

 retractors. Ampullae double, tube feet with sucking disks. 



The papular areas are not so extended in large specimens as in C. japonicus. 

 They are found in center of disk, inside a circle bounded by the primary basal plates, 

 and on a fairly broad petaloid radial .area. They are absent on an extensive trian- 

 gidar interradial area. The abactinal plates of the radial areas show faint lobes 

 and are closely juxtaposed, allowing only a small space for the papulae to pass 

 between. Interradially the plates are regular, closely joined, and in form, square 

 near center, then hexagonal or pentagonal, and finally rhomboid near margin. 



Type. — In British Museum. 



Type-locality. — Cliallenger station 313, near the Atlantic entrance to the 

 Straits of Magellan, 55 fathoms, sand. 



Distribution. — Vicinity of Cape Horn, Gulf of California, southern Alaska to 

 the southern part of Bering Sea (east to Commander Islands). 



Specimens examined. — Xine from the follo\ving localities: Albatross station 

 3223, Bering Sea, near Unalaska Island, 56 fathoms, black pebbles, two; 2856, 

 near Ka<liak Island, 68 fathoms, gray shells, one; 3257, Bering Sea, near Unalaska 

 Island, 81 fathoms, gray sand, gravel, two; 3548, north of Unimak Island, Aleu- 

 tians, 91 fathoms, black sand, one; 4228, vicinity of Xaha Bay, Behm Canal, 

 southeast Alaska, 41 to 134 fathoms, gravel, sponges, one; 4791 near Bering Island, 

 76 fathoms, rocky, one; small bay north of Carmen Island, Gulf of California, one 

 (Stanford collection). 



