110 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



lobes. Well developed atrial velum present at base of short atrial 

 siphon. About 15 longitudinal muscles on dorsal half of each side 

 of thorax, converging at atrial aperture, dorsal muscles rather fine; 

 about a dozen oblique muscles on ventral half of each side of thorax, 

 converging at dorsomedian line between dorsal ganglion and atrial 

 siphon. A very strong longitudinal muscle running along each side 

 of endostyle. Many fine transverse muscles beneath longitudinal 

 musculature, as many as 80 in larger zoodis. All longitudinal muscles 

 converge posteriorly to a pair of longitudinal muscle bands running 

 down along ventral side of abdomen, the right band is stouter than 

 the left. In zooids examined 22-28 stigmatal rows, about 50 stigmata 

 in each row. Tentacles 32, larger alternate with smaller ones rather 

 regularly; ciliated groove an elongated slit; dorsal languets situated 

 on dorsomedian line. Horizontal membranes well developed along 

 respective transverse vessels. Stomach begins roughly from middle 

 of abdomen, elongate and about a fourth as long as abdomen, with 

 five distinct longitudinal crests besides a typhlosole. Hind stomach 

 and midintestinal portion clearly defined, the latter strongly con- 

 stricted at middle. A small but distinct depression on each side of 

 proximal portion of rectum. Wall of rectum between level of middle 

 of hind stomach and anterior end of abdomen covered with whitish 

 circumintestinal gland which consists of a number of fine tubules 

 running lineally and parallel to one another near proximal end of 

 rectum, but are very complicatedly entangled on distal parts. Anus 

 bilobed, situated slightly anterior to dorsoposterior corner of thorax ; 

 usually four or five stigmatal rows present posterior to the edge of 

 membrane connecting anus with branchial sac. Testicular follicles 

 small, very numerous and distributed on left side of intestinal loop 

 posterior to middle of stomach. 

 Distribution. — West Indies. 



47. Eudistoma pyriforme (Herdman) 



Figure 38 



Psammaplidium pyriforme Herdman, 1886, p. 419. 



Eudistoma pyriforme Hastings, 1931, p. 83, fig. 7D.— Tokioka, 1950, p. 120, fig. 4. 



MATERIAL EXAMINED 



Paiau Islands : Madalai district, west end of Koror Lsland ; GVF sta. 12. One 

 specimen (USNM 11402). 



GiLBEET Islands: Onotoa Atoll; P. E. Cloud, sta. GOC-59. Two small col- 

 onies (USNM 11476), attached to underside of Didcmnum (D.) candidum 

 Savigny (USNM 11514). 



Description. — A single large colony from the Palau Islands was 

 examined. It is roughly roundish in shape, about 55 mm. in diame- 

 ter and 14 nmi. in thickness. It consists of two cormidia, one much 

 smaller than the other. The surface of the colony is nearly smooth 

 and dull purplish brown in alcoholic preservation. 



