30 PROCEEDINGS OF THE NATIONAL. MUSEUM vol.88 



second testis. Ovary on right side in front of first testis, from wliich 

 it is separated usually by a space approximately equal to its own 

 diameter, and usually a little in front of the level of the ventral 

 sucker; shell gland at posteromedian border of ovary. The viteilaria 

 are arranged in a somewhat arcuate cluster of follicles on each side 

 from about the level of the ventral sucker to the level of the posterior 

 border of the anterior sucker. The lateral clusters of follicles may or 

 may not meet in the midventral region behind the anterior sucker. 

 The folds of the uterus are widely distributed, and may extend from 

 the posterior end as far forward as the level of the anterior border 

 of the sacculate intestine, or farther. The ova are very numerous; 

 they measure about 0.018 by 0.015 mm. in balsam, and have thickish 

 shells. 



Host. — Flasher {Lobotes surinamens'is) . 



Record of collections. — Nine (U.S.N.M. No. 8174) , collected August 

 1, 1918. 



PROSORHYNCHUS GRACILESCENS (Rudolphi) 

 Plate 18, Figijbes 245-249 



Qasterostomum sp. Linton, BuU. U. S. Fish Comm. for 1899, pp. 277, 298, fig. 91, 



1900 ; ibid. p. 442, 1901. 

 Gasterostomum gracilescens Rudolphi, Linton, Bull, U. S. Bur. Fish., vol. 24, 



p. 335, figs. 230-232, 1905. — Waguer, Tennent, Quart. Journ. Micr. ScL, vol. 



49, pp. 635-690, pis. 39-42, 1906. 



I refer to this species certain gasterostomes of very diverse shape, 

 frequently occurring in the garfish {Strongylura marina) and simi- 

 lar forms and found less frequently in the silversides {Menidia 

 notata) and other Woods Hole fishes. 



These forms vary i]i size, shape, and relative positions of the geni- 

 talia. The body, densely covered with small, scalelike spines, is 

 usually more or less fusiform. The anterior sucker is relatively large 

 and ventrally placed. The anterior end varies from capitate to 

 bluntly and evenly rounded. The ventral sucker is usually a little 

 in front of the middle, but, in strongly contracted specimens, it may 

 be about the middle; it is subglobular and joined to the oval-ellip- 

 tical, or pyriform, intestinal cecum by a short esophagus. The intes- 

 tinal cecum is directed toward the anterior end. The cirrus pouch is 

 relatively large, on the left side, its posterior portion thin-walled and 

 more or less coiled in contracted specimens; the anterior portion is 

 thick-walled, and encloses the seminal vesicle at its anterior end. The 

 testes are usually diagonally placed, the second near the right side 

 with the first at its anteromedian edge. They are not far from the 

 middle of the length. They may, however, be crowded into various 

 positions by the accumulating ova. In some cases they may lie, one 



