298 EUG. DADAY DE DEÉS 
arcuatus, in marginem dorsalem ventralemque sine limite visi- 
bili ineuns. Margo dorsalis rectus, longitudine dimidia concha- 
rum, in marginem posleriorem sine limite visibili ineuns. 
Fig. 67. — Cyzicus sibericus Dad. n. Sp. — a, Q concha a latere, 1 : 3; 0, o'concha 
a latere, 1 :3: ce, o caputa latere, 1 :5:4, © conchae supra visac, 1 :3:e, oO conchae 
Supra visae, 1 : 3; f, © caput a lalere, 1 : 5; g, © pars apicalis pedum primi 
paris. Reich. Oc. 1, Obj. 0; X, o' pars apicalis peduim 2-di paris. Reich. Oe. 1}, 
Obj. 0:12, & © aculei telsoni marginales. Reich. Oc. 1, Obj. 2: X, © pars apicalis 
pedum primi paris. Reich. Oc. I, Obj. 0 ; {, & © pars valvulae concharum. Reich. 
Oc. TI, Obj. 0; m, © telsonum et segmenta aliquot antecedentia. Reich. Oc. I, Obj. 0: 
n, © pars apicalis pedum 10-mi paris. Reich. Oc. 1, Obj.0:; 0, ovum. Reich. Oec. 1, 
Obj. 2. 
Margo posterior regulariter et sat acutiusculo arcuatus, in 
marginem ventralem parum ventricose rotundatum sine limite 
visibili ineuns (fig. 67, 4). 
Conchae infra vel supra visae sat late fusiformes, latitudine 
maxima in medio sila ; apice anteriore posteriore parum bre- 
