NO. 1558. 



NORTH PACIFIC HOLOTHTJRIANS— EDWARDS. 



57 



. — CUCUMARIA CALCIGERA. SPIN08E, 

 Kt)RATED TENTACLE ROD. (X llOf.) 



Disks. — Arched, elongated, wider at the middle, with, four central 

 holes and one to four holes in the ends of the two rays (fig. ^a-h). 



Size of disk in inlUimeters. — Length 0.09 to 0.17, average 0.13; 

 height of arch 0.02 to 0.06, average 0.05; width at middle 0.03 to 

 0.08, average 0.04; width of ends about one-half of that of middle. 



Spire. — Composed of rods not so much fused as in the tables of the 

 body wall, leaving one proximal hole, none to six distal holes, and 

 sometimes a distinct hole between the proximal and distal holes (fig. 8). 

 The spire is often compressed. The spires are longer and more slender 

 than those drawn by Bell, 1883 (Plate VIII, fig. 2«), and Ludwig, 1886 

 (Plate VI, fig. 5). The figures 

 of Bell are intermediate between 

 that of Ludwig and my own, so 

 that I think all may be taken as 

 within the range of variation. I 

 have often noticed spires which 

 have been broken oft' that resemble Bell's figures. 



Size of s_pire in niiUimeters. — Height 0.03 to O.Oi), average 0.05; 

 diameter at base 0.02 to 0.04, average 0.03; at crown 0.008 to 0.03, 

 average, 0.02. 



Cnnrn. — Four to twenty generally simple teeth arise from the end 

 and sides (fig. 8/>). The crown may be compressed or rounded. 



Terminal plate. — Holes may be all of the same size, or small at the 

 center and larger peripherally, or vice versa. 



Diameter in miUi meters. — 0.11 to 0.15, average 0.12. 



Spicules of tentacles. — Supporting rods of 

 very diverse form, occasionally irregular 

 plates. The rods (fig. D) are spinose and per- 

 forated. The plates also may bear spines. 

 The spicules are apparentl}^ adapted in curva- 

 ture and size to the special parts of the tenta- 

 cles in which they occur. The plates are 

 usually found in the terminal branches and 

 resemble those of the introvert, except in 



Fig. 10.— Cucumakia calcigera. 

 Fragment of calcareous 

 ring network. (x 340.) 



size. 



Size in millimeters — Tentacular supporting rods. — Length 0.14 to 

 0.72, average 0.35; width 0.008 to 0.11, average 0.05. Plates 0.06 

 to 0.18, average 0.1; width 0.02 to 0.08, average 0.05. 



Calcareous ring. — Of ten rather slender species, each being made up 

 of a calcareous network (fig. 10), rather thicker in places, and there- 

 fore appearing composite. Radialia shallow-tailed posteriori}-, the 

 two prolongations extending to the ring canal. Interradialia wedge- 

 shaped, pointed anteriorly. 



Polian vesicle. — One, distended, pear-shaped. Length 0.7 to 1.2 

 mm., average 0.85 mm. 



