V)92 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxvi. 



h Natatory sette of second antennje reaching to tips of terminal claws. Shell pale 



green rlllosn * ( Jurine). 



hi) Natatory seta? of second antennjc reaching beyond tips of terminal claws. Shell 

 grass-green, at least dorsally .wiarcu/dina ( Vavra) . 



8. POTAMOCYPRIS SMARAGDINA (Vavra). 



Plate LXV, figs. 5-7. 



Ci/pridopsi)^ sii)anit/dl))a Yavk.\, Monog. der Ostrac. Bohmens, Arch. Naturw. 

 Dnrchforsch. v. Bohmen, VIII, 1891, p. 80, fig. 26, 1-3.— Sharpe, Cont. to a 

 Knowl. of the N. American freshwater Ostracoda inch in the fam. Cytheridae 

 and Cyprididc-e, Bull. 111. State Lab. Nat. Hist., IV, 1897, ]>. 470, pi. xlvii, 

 figs. 11-12. 



QindoneUa smaragdi)ia Vavka, Siisswasser-Ostracoden der Hamb. Magal. Sammel, 

 1898, p. 12; Hamburg. 



Leng'th, ().«)5 mm.; height, 0.45 mm.; ])readth, 0.34 mm. 

 I horc give the description as given in my paper of 1897: 



This striking and interesting form appears at first glance, if seen from the side 

 (fig. 6), to be in the shape of a half moon, except that the ventral margin is nearly 

 straight. The shell is light to grass gi'een, especially on its dorsal aspect; alcoholic 

 specimens, however, commonly show but a trace of this coloration. Surface thickly 

 covered with long hairs, which are all parallel to one another, backwardly directed 

 and closely appressed to the shell (fig. 6). 



The eye-spot, instead of being at the highest part of the shell, as in tlie typical 

 forms described by Vavra, is slightly below and anterior to this location. Natatory 

 set;e of the second antenna*, long, reaching beyond the tips of the terminal claws by 

 the length of the claws, thus differing from C. villom. (Jurine), its nearest relative, 

 the natatory setie of M'hich reach l)ut to the end of the terminal claws. 



Furca rudimentary (fig. 7), the basal part cylin(b'ical, more than three times as 

 long as wide, then suddenly narrowing into a long tlagelhnn, which is fully twice as 

 long as the basal part. The furca also has a dorsal seta at the termination of the 

 basal part, which is slightly longer than the width of the ramus. 



At the time the above description was written, I was not sufficient!}^ 

 familiar with the genus Potafmocypris to rank this form as belonging 

 to it. Further study causes me to believe that this genus is a logical 

 one, and that this form belongs here. 



The specimens in the U. S. National Museum were collected in April, 

 1901, by Dr. Alfredo Duges, French consular agent at Guanajuato, 

 Mexico. 



This form occurs in Bohemia (Vavra); South Chicago (Sharpe), and 

 Guanajuato, Mexico. 



23. PARACYPRIDOPSIS Kaufmann, 1900. 



('[/jyridopxis Brady and Nor>[an, A Monog. of the marine and freshwater Dstra- 



coda, Sec. I, Trans. Royal Dublin Soc, 1889, p. 90. 

 Paracypridop.^is Kaufmann, Cypriden and Darwinuliden der Schweiz, Revue 



Suisse de Zool., VIII, 1900, p. 131. 



Shell rather nai-row from al)ove. Natatory seta^ rudimentary, not 

 ada])t(Ml for swinuniiig. Furca rudimentary, lamellar, with a lash-like 

 end bristle and a small dorsal seta. Branchial plate of two seta?. 



