NO. 3587 OSTRACODS — HOBBS 5 



10' Horizontal ramus of clasping apparatus with more than one tooth on 



internal border 11 



11(10') Width of clasping apparatus at major bend less than two times least 



width of vertical ramus runki (Hol)bs, 1955, p. 330) 



11' Width of clasping apparatus at major bend more than two times least 



width of vertical ramus 12 



12(11') Peniferum with prominent hump on posterior margin paralleling ac- 

 cessory groove; posterior margin of finger guard strongly concave, 

 distal end with single emargination. 



xystroides (Hoi)bs and Walton, 1983, p. 400) 

 12' Peniferum without prominent hump on posterior margin paralleling 



accessory groove; posterior margin of finger guard only slightly 

 concave, distal end with two emarginations. 



pachysphyrata (Hobbs and Walton, 1966, p. 3) 



13(9') Finger guard with three distinct distal tubercles 14 



13' Finger guard with less than three distinct distal tubercles .... 15 

 14(13) Posterodistal thickening of peniferum distinctly rounded with opening of 

 peniferal groove directed anteriorly; apical portion of clasping appa- 

 ratus serrate suteri (Crawford, 1959, p. 162) 



14' Posterodistal thickening of peniferum angular with opening of peniferal 



groove directed anteroventrally; apical portion of clasping apparatus 



with teeth but not seri'atc . . . chelomata (Crawford, 1961, p. 242) 



15(13') External border of vertical ramus of clasping apparatus with angular 



shoulder 16 



15' External border of vertical ranuis of clasping apparatus entire, rounded. 



17 

 16(15) Internal border of horizontal ramus of clasping apparatus with four 



teeth, distal extremity with two phoxa, new species 



16' Internal border of horizontal ramus of clasping apparatus with two teeth, 



distal extremity with three jeanae, new species 



17(15') Vertical ramus of clasping apparatus wider than horizontal ramus, 

 extremities directed subparallel to each other. 



steevesi (Hart and Hobbs, 1961, p. 180) 

 17' Vertical ramus of clasping apparatus not wider than horizontal ramus, 



extremities directed at angle of 35° to 50°. 



ungulata (Hart and Hobbs, 1961, p. 177) 

 18(4) Shell with antero ventral protuberance. 



amphiakis Hart and Hart (1966, p. 3) 

 18' Shell without antero ventral protuberance. 



daphnioides (Hobbs, 1955, p. 325) 

 19(7') Three proximal teeth on internal border of horizontal ramus of clasping 

 apparatus subequal in size and eciually spaced. 



arcuata (Hart and Hobbs, 1961, p. 177) 

 19' Proximal tooth on internal border of horizontal ramus of clasping appar- 



atus much larger than following two and widely separated from them. 



amicula Hart and Hart (1966, p. 1) 

 20(8) Height of horizontal ranuis of clasping apparatus at level of proximal 

 tooth almost twice that of height at level of third tooth. 



brachystrix Hobbs and Walton (1966, p. 2) 

 20' Height of horizontal ramus of clasping apparatus at level of proximal 



tooth only slightly more than that of height at level of third tooth. 



exoura Hart and Hart (1966, p. 5) 



228-9G9— 66 2 



