458 PROCEEDINGS OF THE NATIONAL, MUSEUM vol.89 



LATOCESTUS WHARTONI (Pearse, 1938), new combination 



FiGTJBB 25. 6 



Oculoplana whartoni Pearsej, 1938, p. 83, fig. 30. 



Mateiial. — Twenty-three whole mounts labeled by Pearse Oculo- 

 plana whartoni^ including the type specimen; one of whole momits 

 made into sagittal serial sections. 



Form. — Long and slender, about 8 times as long as wide in life; 

 maximum length in life 36 mm., width 3 mm.; ends rounded; thin, 

 mobile, sides parallel (for figure see Pearse, 1938, fig. 30). Sucker 

 mentioned by Pearse and shown in his figure does not exist ; that which 

 Peai*se so labels is merely an accidental fold of the margin. 



Eyes. — ^Marginal band along entire margin, two or three rows wide 

 anteriorly, thinning to a single irregular row posteriorly. Numerous 

 small eyes strewn over anterior end, beginning medially behind the 

 brain, extending anteriorly along the main nerve trunks (exaggerated 

 in Pearse's drawing), then spreading fanlike over the anterior end 

 to merge with the marginal eyes. 



Color. — Uniform yellowish white. 



Digestive tract. — Oval ruffled pharynx near posterior end; long 

 main gut extends forward from this to behind brain giving off on each 

 side niniierous side branches; main gut forks behind brain and the 

 forks run forward alongside main nerve trunks giving off branches 

 obliquely forward (Pearse's figure of anterior gut branches erroneous) . 



Reproductive system. — Vasa deferentia and uteri seen along main 

 gut in posterior third of body. Vasa deferentia have slightly muscu- 

 lar walls as they approach penis, hence do not form well-developed 

 accessory seminal vesicles as in some other Latocestus species. Sec- 

 tions of copulatory apparatus poor because of bad histological state 

 of available specimens. Male copulatory apparatus immediately be- 

 hind pharynx. Prostatic vesicle free, of elongate oval form with 

 thick muscular wall ; it leads directly to conical penis papilla at inner 

 end of short, narrow male canal leading to male genital pore (fig. 

 25, h). Vasa deferentia unite to common vas deferens, which joins 

 duct of prostatic vesicle in the penis papilla. Female pore shortly 

 behind male pore, larger than this; vagina runs dorsally, then curves 

 posteriorly, and enters sausage-shaped transverse Lang's vesicle (fig. 

 25, h). Vagina accompanied by numerous cement glands, not muscu- 

 lar. Lang's vesicle variable in different specimens : narrow and trans- 

 versely elongated in some, shorter and stouter in others; often with 

 folded or irregular wall. Entrance of uteri could not be found. 



Distribution. — Florida, North Carolina. 



Habits. — On shells in shallow water. 



