180 



UNITED STATES NATIONAL MUSEUM BULLETIN 251 



Transverse vessels arranged : thick thin medium thin tliick ; parastig- 

 matic vessels nearly absent, only a few found sparsely in posterior 

 part. Elongated stigmata 5 to 7 in each mesh. Tentacles 26-28, 

 purplish black, larger and smaller ones differentiated. Ciliated groove 

 U- or Y-shaped. Second intestinal loop practically indistinguishable. 

 Stomach elongated with about 6 plications on each side and a very 

 prominent pyloric caecum (fig. 74e). Rectum long, anal margin 

 plain. Numerous small gonads spread over entire inner surface of 

 mantle (figs. 74&, c, gonads shaded with dots, endocarps left blank). 

 Gonads roundish in shape, much smaller than endocarps, about 0.5 

 mm. in diameter and each contain several eggs and very small testicular 

 follicles up to about 15 in number, occupying peripheral part of 

 attachment surface. 



90. Polycarpa species 



Figure 75 

 MATERIAL EXAMINEU 

 Palau Island : Barrier reef 8 mi. NW. of Koror Island : GVF sta. 25. One 

 specimen (USNM 11387). 



Description. — A partly mutilated specimen from the Palau Islands 

 was examined. Body elongated, attached to substratum by the ventral 

 side and probably attains 24 mm. in length. Branchial aperture sub- 

 terminal, atrial aperture nearly at middle of body. Middle part of 

 animal, posteriorly including intestine and anteriorly covering ciliated 

 groove, considerably mutilated. Test yellowish white, thin but very 

 tough in consistency; inner surface w^hitish and partly with pearly 

 glistening. Tips of siphons of mantle body reddish. Fine tentacles 

 along the atrial velum. In branchial sac inner longitudinal vessels 

 are (D= dorsal, V= ventral) : 



Left D broken (16) 8 V 



Right D 7 (8) 11 (17) 8 (20) 10 (13) 9 V 



Transverse vessels arranged: thick p thin p thick (p=parastigmatic 

 vessel). Two or three stigmata in each mesh, may be up to six in 

 meshes along endostyle. Tentacles at least 14, larger and smaller ones 

 alternate regularly. Dorsal lamina a plain membrane. Only the oval 



rr 



?^<^^'^"^%i5^ 



%?^^^^^' -^t 



a 



Figure 75. — Polycarpa species: a, The specimen; b, lefi side of stomach; c, gonad. 



