NO. 1989. A8CIDIAN8 FROM NORTHEASTERN PACIFIC— RITTER. 441 



EUGYRIOIDES DALLI, new species. 

 Plate 33, figs. 1-3. 



Superficial characteristics. — Quite regular iii form, varying from 

 nearly spherical to oblong; siphons conspicuous because of their 

 opaque whiteness as contrasted with the transparency of the test 

 generally; projecting distinctly, though not greatly above the general 

 surface, considerably harder than the rest of the body, so that the 

 general appearance of the structures is that of two warts ; the siphons 

 rather near together, the atrial more toward the end of the body in 

 oblong individuals. Test transparent, permitting the internal or- 

 gans to be distinctly seen where the adhering sand grains (abundant 

 m some individuals) are not too numerous. A great number of fine, 

 flaccid filaments on the surface of the test, these almost uniformly 

 distributed over the whole body. Anunals unattached, apparently 

 livmg on sandy bottoms. Largest individual about 30 mm. in diame- 

 ter and nearly spherical; most individuals smaller. Mantle rather 

 thin, musculature not strongly developed. Radial fibers much 

 larger and stronger than circular, the former reaching back radially 

 from each siphon not quite to the equator of the body; regularly 

 spaced. 



Respiratory system. — Branchial orifice 6-lobed, atrial 4-lobed, both 

 sets of lobes rather obscure. The small lobes of the branchial orifice 

 irregularly notched (pi. 33, fig. 1). Branchial tentacles about 50 of 

 various sizes, about 12-15 large ones; sparsely and very uTegularly 

 branched, secondary branches being present though scarcely more 

 than buds (fig. 2). Hypophysis mouth round, horseshoe-shaped, 

 turned strongly to the right, the ends of the shoe simple, approaching 

 each other rather closely. Ganglion very close to the hypophysis. 

 Dorsal lamina undivided, smooth. Branchial sac without folds, but 

 with seven prominent, longitudinal membranes occupying the posi- 

 tion of the folds, each of these having a thickened, rounded edge 

 which may be regarded as a single longitudinal vessel. Stigmata 

 mostly strongly curved and disposed m infundibula wliich are of two 

 orders, those with apices along the longitudinal vessels and those 

 between the vessels and so with apices entirely independent of the 

 vessels (pi. 33, fig. 3). 



Alimentary system. — Situated on the left side, the whole forming 

 roughly a semicircle with a double periphery from the intestines 

 bending back rather sharply on itself, and so making the rectal por- 

 tion run for some distance nearly parallel to the esophagus and 

 stomach. Stomach not distinctly set off from the intestine, its wall 

 thrown into a number of large irregular convolutions (pi. 33, fig. 1). 

 (The course of the intestinal canal in the specimen here figured is not 

 quite typical in that the space left between the two limbs at the point 

 of doubling back is wider than usual.) 



