202 UNITED STATES NATIONAL MUSEUM BULLETIN 251 



stigmatic vessels absent. Five to six elongated stigmata in each mesh 

 in larger specimens, but only approximately two elliptical stigmata in 

 a mesh in the smallest individual. Large tentacles about 10, smaller 

 ones of same number; order of branching is two in larger specimens, 

 but only first order is defined in smallest one. Ciliated groove simply 

 U-shaped. First intestinal loop long, attaining two-thirds to three- 

 quarters of body length. Esophagus long. Gastric region elongated, 

 rectum swollen at bottom of second intestinal loop, anal margin cut 

 into 7-11 lobules. Liver olive brown or brownish, distinctly divided 

 into two parts in larger specimens, smaller anterior part consisting of 

 a number of elongated finger-shaped hepatic lobules, larger posterior 

 part consisting of a few complicatedly ramified protuberances of gas- 

 tric region, which end distally in tufts of minute finger-shaped hepatic 

 lobules (fig. 88^). 



Gonads, especially the right, strongly curved in distal half; genital 

 capsules each provided with an elongated endocarp on surface; endo- 

 carps of genital capsules of dorsal series larger than those of ventral 

 series; 27-29 genital capsules on each side in larger specimens. Tes- 

 ticular follicles 10-25 on each capsule, occupying free surface ; ovary 

 located on attachment side. In smallest specimen gonad not mature, 

 although a series of endocarps are on each side just at situation of 

 gonad. Another series of endocarps found along outer side of intes- 

 tinal loop on left side. 



105. Pyura vittata (Slinipson) 



FiGtJKE 90 



Cynthia vittata Stimpson, 1852, p. 230. 



Pyura vittata Van Name, 1945, p. 321, figs. 213-215; pi. 16, fig. 5 (synonymy).— 

 Tokioka, 1953a, p. 273, pi. 3, figs. 3-4 ; pi. 66, figs. 1-5 (synonymy). 



MATERIAL EXAMINED 



Palau Islands : Iwayamn Bay ; south end of Island XX. GVF sta. 134. One 

 specimen (USNM 11462). 



Description. — A single 10 nun. long specimen from the Palau 

 Islands attached to the substratum by the right ventral side was 

 examined. Test milky white, with slightly yellowish tint around 

 apertures, translucent and soft, but very tough; surface nearly 

 smooth except for several wrinkles formed by contraction. Mantle 

 extremely thin, yellowish white. Both siphons long, yellowish 

 orange; apertures 4-lobed. About 10 longitudinal and transverse 

 muscles, crossing each other regularly, around base of atrial siphon, 

 basal portion of branchial siphon so mutilated that exact arrangement 

 of muscles cannot be seen. Spinules on the inner surface of siphons 

 slender (fig. 90/), 76/* in length on an average. 



Six folds on each side of branchial sac. Inner longitudinal vessels 

 arranged (D = doi"sal, V= ventral) : 



