2 PROCEEDINGS OF THE NATIONAL IMUSEUM vol. 119 



naldsoncythere, Entocythere, the new genus Thermastrocy there, and 

 Unicnocythere. 



We wish to thank the following persons who have made available 

 to us the collections on which this paper is based: Messrs. J. W. Berry, 

 C. W. Hart, Jr., J. M. Stubbs, Drs. Fulton Fite, P. C. Holt, L. R. 

 McManus, G. C. Smart, P. J. Spangler, and W. S. Woolcott. 



G^nus Dactylocythere Hart, 1962 

 Dactylocythere brachystrix, new species 



Figures la-d 



Male. — Eye present. Shell (fig. 16) with highest portion posterior 

 to midlength and with dorsal and ventral margins more gently 

 tapered anteriorly than posteriorly; ventral margin of shell entu-e; 

 submarginal setae anteriorly, ventrally, and posteriorly somewhat 

 evenly spaced, absent dorsally. Range of shell size of 10 specimens 

 recorded in table 1. 



Copula tory complex (figs, la, d) with posterior margin of peniferum 

 expanded into three humps; both anteroventral and posteroventral 

 extremities directed anteroventrally. Penis small, its length approxi- 

 mately one-third the anterior-posterior dimension of distal portion 

 of peniferum, and situated at level of base of ventral two-fifths of 

 peniferum. Accessory groove extending dorsally almost to ventral 

 extremity of spermatic duct. Dorsal finger slender with its terminal 

 seta extending to ventral margin of finger guard ; ventral finger gently 

 curved throughout its length. Finger guard prominent with its 

 anterior margin straight and its ventral margin emarginate with 

 three small prominences. Clasping apparatus with vertical and 

 horizontal rami somewhat distinctly delunited; vertical ramus with 

 a bend of about 45° just proximal to midlength and joining horizontal 

 ramus (external borders) at an angle of about 100°; internal border 

 or horizontal ramus with three evenly spaced teeth and apex with 

 three denticles; external borders of both rami entire. 



Female. — Shell of triunguis female (fig. Ic) distinctly larger than 

 that of male, with its greatest height slightly posterior to midlength 

 and distinctly lower anteriorly than posteriorly; ventral margin entire; 

 marginal setae as in male. Prominent J-shaped rod and ruffled 

 amiculum present. Range of shell size of 8 specimens recorded in 

 table 1. 



Type-locality and range. — Otter Creek, Cumberland County, 

 Tenn., approximately 3.5 miles upstream from the Obed River on 

 the Cumberland Plateau. This species is known only from the type 

 locality where it was found associated with Dactylocythere pachy- 

 sphyrata, new species. 



