NO. 3542 OSTRACODS — HOBBS AND WALTON 9 



are in the collections of C. W. Hart, Jr., and the joint collection of 

 the authors. 



Relationships. — Thermastrocythere harti has its closest affinities 

 with members of the genus Undnocythere (Hart, 1962) and is perhaps 

 more closely allied to U. simondsi (Hobbs and Walton, 1960) than to 

 any other species; similarities exist in the armature of the clasping 

 apparatus and in the distal portion of the peniferum; however, the 

 penis in harti reaches the anteroventral extremity of the peniferum — 

 an arrangement that does not exist in any known species of the genus 

 Undnocythere. 



Remarks. — We are pleased to name this species in honor of our 

 friend and colleague, C. W. Hart, Jr., who has contributed much to 

 our knowledge of the entocytherids. 



Genus Undnocythere Hart, 1962 



Undnocythere stubbsi, new species 



Figures 2a-d 



Male. — Eye present. Shell (fig. 2b) highest near midlength and 

 with dorsal margin evenly contoured anteriorly and posteriorly; 

 ventral margin convex without an emargination; submarginal setae 

 evenly but widely spaced anteriorly, ventrally, and posteriorly, absent 

 dorsally. Range of shell size of 10 specimens recorded in table 1. 



Copulatory complex (figs. 2a, d) with posterior margin of peniferum 

 entire, its ventral margin excised with anteroventral extremity directed 

 ventrally and posteroventral extremity directed an tero ventrally; 

 anteroventral portion with a heavy, acute, dorsally directed penis 

 guide. Penis of moderate size, its length approximately one-half 

 anterior-posterior dimension of distal portion of peniferum and situated 

 far distal to base of clasping apparatus within ventral one-third of 

 area between dorsal margin of spermatic loop and ventral extremity 

 of peniferum. Dorsal and ventral fingers slender, latter with strong 

 caudal bend at distal end of proximal one-third. Clasping apparatus 

 with vertical and horizontal rami of subequal lengths, and extensions 

 of their rounded junction forming angle of less than 90°. Vertical 

 ramus entire but with distal one-third curved posteriorly. External 

 border of horizontal ramus gently rounded and entire; internal border 

 with three teeth — largest immediately proximal to midlength and 

 two smaller ones near distal extremity; terminal extremity with 

 three teeth. 



Female. — Shell of triunguis female (fig. 2c) distinctly larger than 

 that of male with its greatest height slightly posterior to midlength 

 and distinctly lower anteriorly than posteriorly; ventral margin with 



