NEW SPECIES OF FLATWORMS — HYMAN 423 



teriorly. Anterior portions of the ventral nerve cords connected by 

 numerous connectives having a netlike arrangement (not shown in 

 the figure). Digestive tract typically triclad (fig. 47, d) ; pharynx 

 unusually large and prominent. Sections of the pharynx show that 

 the circular and longitudinal fibers of the inner muscular layer are 

 intermingled, as diagnostic of the family Dendrocoelidae. This fea- 

 ture serves to distinguish thei dendrocoelid genus Sorocelis from the 

 planariid genus Polycelis^ which also has numerous eyes. 



Color. — Preserved specimens, imiform yellowish, probably white 

 or creamy in life. 



Histology. — The principal feature is the weakly developed adhe- 

 sive organ, in the center of the ventral surface of the median promi- 

 nence of the anterior margin. This type of adhesive organ is charac- 

 teristic of the genus. It is shown in median sagittal section in fig- 

 ure 48, a. The adhesive organ is a small pit lined with eosinophilous 

 gland cells, whose bodies extend into the adjacent parenchyma, above 

 and below the intestine. The regular surface epithelium containing 

 rhabdites alters abruptly at the margins of the adhesive organ into 

 these gland-cell outlets devoid of rhabdites. Presumably as in other 

 similar organs, there are attenuated epidermal cells between the 

 gland-cell outlets but they could not be seen. Some longitudinal 

 muscle fibers, acting to deepen the pit, extend posteriorly from the 

 organ along the ventral wall where they soon join the regidar sub- 

 epidermal longitudinal muscle layer. General epidermis cuboidal 

 to low columnar, packed with small rhabdites except on the adhe- 

 sive organ and the usual marginal adhesive zone; no special large 

 marginal rhabdites such as occur in other dendrocoelids and the 

 American cave planarians of the family Kenkiidae (Hyman, 1937). 

 Subepidermal musculature moderately developed, weak dorsally, 

 stronger ventrally. Nmnerous cyanophilous gland cells in the pre- 

 pharyngeal region, especially ventrally. Many large eosinophilous 

 gland cells dorsally in the postpharyngeal region. 



Reproductive systejn completely absent. 



Locality. — Bat Cave, Adair County, Okla., collected by A. P. Blair. 

 No date. 



Type.—K^ whole mount, U.S.N.M. no. 20403. Paratypes, as pre- 

 served specimens and serial sections, U.S.N.M. no. 20404. 



Renmrks.—Thi^ is the first finding of the genus Sorocelis, a typical 

 Asiatic genus of fresh-water triclads, on the American continents. 

 The absence of sexual material makes it impossible to differentiate 

 S. aniericana exactly from other species of the genus, but the com- 

 bination of plain; white color, eye arrangement, and locality should 

 suffice to distinguish it. 



