470 PROCEEDINGS OF THE NATIONAL MUSEUM vol.89 



atomata. These came from various points off the coast of Massa- 

 chusetts and from Casco Bay, Maine. 



Genus EUPLANA Girard, 1893 

 Discoplana Bock, 1913. 

 Canjuffuterus Pezakse, 1938. 



Definition. — Leptoplanidae without definite prostatic vesicle; 

 tentacles absent; body usually elongated, more or less slender. 



EUPLANA GRACILIS (Girard, 1850) 



Prostkio^tomum gracile Gikaed, 1850, p. 251. — Verkill, 1893, p. 496, fig. 1. — 



Pearse and Walkeb, 1939, p. 19, fig. 15. 

 Euplana gracilis Girabd, 1893, p. 198, pi. 6, fig. 62.— Peabse and Littleb, 1938, 



p. 238, pi. 20, fig. 6.— Pearse and Walki^r, 1939, p. 18, fig. 13.— Htman, 



1939a, p. 137, figs. 6-8. 

 Conjuguterus parvus Pearse, 1938, p. 81, fig. 29. 



Material. — Many whole mounts labeled by Pearse Conjugufeitis 

 parvus, including type. 



Form. — Small, slender, elongate, anterior end rounded to obtuse, 

 maximum length, 8-10 mm., without tentacles (for figure see Hyman, 

 1939a, fig. 6, p. 137). 



Eyes. — Remarkably few, usually six on each side; tentacular 

 groups consist of two eyes each, cerebral groups of four eyes on each 

 side in an irregular lengthwise row. 



Color. — Yellowish or brownish gray, somew^hat speckled. 



Digestive tract. — Pharynx small, only slightly ruffled, anterior to 

 middle; main intestinal trunk conspicuous behind pharynx; from 

 this lateral branches extend to periphery, not anastomosed. 



Reproductive system. — Described and figured by Hyman, 1939a, 

 fig. 8, p. 137. Description of Pearse (1938, p. 81) erroneous; no 

 prostatic vesicle, no penis papilla, no Lang's vesicle. 



DiMribution. — Florida to Prince Edward Island, common. 



Habits. — Active, among seaweeds, hydroids, tunicates, etc., on 

 pilings, also among old shells, littoral. 



Remarks. — This species was wrongly placed by Pearse and con- 

 sidered a type of a new genus, Conjuguterus, which is a synonym 

 of Eupla'na. In Pearse ar^d Littler and Pearse and Walker the name 

 was changed to Euplana gracilis (in consequence of infcraiation 

 received from me in letters), but it was nowhere indicated that this 

 was the same species previously called Conjuguteru.^ parvus nor was 

 the erroneous familial placing corrected. In Pearse and Walker 

 Euplaiia gracilis and Rrostkiostomum, groxiile are presented as dis- 

 tinct species and each is figured; the figure of the latter appears to 

 have been constructed by slightly altering Prosthiostomum Jobatum, 

 a genuine species of Prosthiostomuvi. As I already pointed out 



