ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS — FISHER 71 



straight pedicellariae on the adambulacral plates, but occasionally a large spatulate 

 unguiculate pedicellaria stands on the actinal surface of the proximal plates. 



The mouth plates (pi. 29, fig. 1) have the usual form and carry a longitudinal 

 series of five slender spines, of which the two inner (actinostomial) are the shortest; 

 and the outermost (just external to middle of plate) is subequal to the longest adjacent 

 subambulacral. A short sixth spinelet stands on the furrow margin in a transverse 

 direction to the outermost suboral. There is no trace of small straight pedicellariae 

 on the mouth plates, but in one mouth-angle each plate carries a large unguiculate 

 spatulate pedicellaria. 



The crossed pedicellariae are numerous and alternate with the spinelets on the 

 skeletal net. Occasionally two stand between a pair of spinelets, and one to three 

 are found on the membrane of most of the papular areas. They range in length from 

 0.27 to 0.4 mm., the largest being actinal, and are characterized by numerous teeth 

 (about 10) on the vertical series of each jaw. (PI. 29, figs, lc, Id.) 



Straight pedicellariae: On the actinal plates near the interbrachial angle there 

 is usually a single large spatulate pedicellaria with three or four long curved teeth. 

 It resembles in miniature a pair of clasped hands and is 0.9 to 1 mm. long. Several 

 of the same sort, but narrower and with sometimes only two teeth, stand on the proxi- 

 mal adambulacral plates or on the outer end of the oral plates. There are no small 

 lanceolate straight pedicellariae. (PI. 29, fig. la.) 



Madreporic body fairly large, near margin. 



Anatomical notes. — The gonads open in the interval between the inferomarginal 

 and the actinal plates, about 6 mm. from the interbrachial angle. Each gonad con- 

 sists of several small branched tufts, the lobules being irregular in form and unequal 

 in length. The ampullae are rather large, not divided, and the tube-feet are in two 

 series. A peculiarity of the species seems to be the entire absence of an interbrachial 

 septum. There is no membrane nor continuation inward of the interbrachial skeleton. 

 There is therefore a free space interradially between the interbrachial ridge and the 

 inner border of the actinostome. 



Type.— Cat. No. E. 1421, U.S.N.M. 



Type-locality. — Station 4427, 7 miles southwest of Point San Pedro, Santa Cruz 

 Island, Calif.: 447 to 510 fathoms, black mud, rocks; April 14, 1904. 



Distribution. — Known only from the type-locality. 



ANTELIASTEIt COSCINACTIS MEGATRETUS, new subspecies 



Plate 29, Figures 2, la, 26; Plate 35, Figures 5, 5a 

 Pedicellasler improvisus Clark, not Ludwig, Bull. Araer. Mus. Nat. Hist., vol. 32, 1913, p. 202. 



Diagnosis. — Rays 5. R 77 mm. (longest ray) ; r9mm.; R = 8.5 + r; disk small; 

 rays slender, weak, flexible. Differing from A. coscinactis in lacking straight pedi- 

 cellariae, in having a more open skeleton with larger meshes (two dorsolateral series) 

 slenderer plates, more delicate spinelets (with fewer terminal thornlets), and slenderer 

 crossed pedicellariae. 



Description. — The skeleton is more open than in coscinactis. Along the side of 

 tho ray there are four longiseries of large quadrilateral meshes which are normally 

 regular, although on some rays the longitudinal trabeculae disappoar so that two or 



