POLYCLAD WORMS COLLECTED ON THE 

 PRESIDENTIAL CRUISE OF 1938 



By LIBBIE H. HYMAN 



American Museum of Natural History, New York City 



The material consisted of four vials of polyclacls collected at vari- 

 ous points along the shores of the Galapagos Islands and Old Provi- 

 dence and Clipperton Islands by Dr. Waldo L. Schmitt during the 

 Presidential Cruise of 1938. Each vial contained a different species 

 represented in three vials by a single specimen, in the fourth vial by 

 two specimens. All of the worms were badly crumpled and folded 

 and it was necessary to straighten them out forcibly before any work 

 could be done on them. This has resulted in some distortion of parts 

 and has produced folds and wrinkles in the body surface, but the 

 material is adequate for the determination of the necessary points of 

 anatomy. All of the specimens were stained as whole mounts with 

 dilute acidified borax carmine and, after they were studied and drawn, 

 the sexual region was removed in the case of three species and cut 

 into sagittal serial sections. The study of the material has shown that 

 it comprises two species of N otoplana, one of Euplana, and one of 

 Prosthiostomum, all of which appear to be undescribed forms. 



JfOTOPLANA INSULARIS, n. sp. 



Figs. 1-3 



Description. — The single specimen, somewhat contracted and folded 

 (fig. 1), is 9 mm. long and 3 mm. wide at the widest part, obviously 

 much longer in life, of elongated oblong shape, tapering somewhat 

 posteriorly. Color not determinable. Pharynx small with a few folds, 

 embraced by the uteri which come to a point anteriorly behind the 

 brain. Eyes (fig. 2) in paired elongated bands, tentacular clusters 

 thus not separated from cerebral groups ; tentacular groups evident 

 as rounded group in each band at about the level of the middle of 

 the brain. Eyes unusual in that cerebral eyes are of the same size as 

 tentacular eyes. Posterior half of specimen made into serial sections. 

 Copulatory apparatus (fig. 3) typical of the genus. Seminal vesicle 

 oval, with thick muscular wall of fibers parallel to the surface con- 

 tour. Ejaculatory duct curves backward and after a short course 



Smithsonian Miscellaneous Collections, Vol. 98, No. 17 



