no. 1651. REPORT OX THE OSTRACODA—8HARPE. 4Q7 



Seen from above (Plate L, figs. 1, 2), the shell is very broadly oval, 

 even approximately subcircular, so plump is it. Right valve slightly 

 overlapping left anteriorly. 



Palps of the right and left maxilla? of the male (Plate LV, fig-. I. 

 G) with hooked terminal segments, these each terminating with a 

 recurved hyaline tip. As is usual with the genus S piracy pris, the 

 testes of the male arise in a number of concentric circles in the ante- 

 rior part of the shell (Plate LIV, fig 4). and after separating into two 

 groups just back of the eye-spot, extend postero-ventrally. 



Natatory setae simple, extending but slightly beyond terminal claws. 



Terminal claws toothed at tip, the three larger the same length, and 

 somewhat longer than the penultimate segment. 



Terminal claws of the first feet strong, toothed at tip, slightly 

 curved, and about one-half longer than the penultimate segment. 



Terminal claws of second feet (fig. 1) one and one-half times 

 length of terminal segment. Terminal segment beak-shaped; ter- 

 minal reflexed seta about twice as long as terminal claw. 



Ejaculatory duct of male in sack (fig. 2) elongate and narrow, and 

 with about 20 wreaths of spines. 



Furca nearly straight, very slender (fig. 3), about 32 times as long 

 as average width ; dorsal margin smooth. Terminal claw nearly 

 straight, very faintly pectinate at tip, one-half as long as furca; 

 subterminal claw four-fifths as long as terminal one. Terminal seta 

 less than two-fifths as long as terminal claw. Dorsal seta slender, 

 twice width of furca from subterminal claw and reaching about to 

 tip of furca. 



This form differs from Spirocypris passaica, the only other de- 

 scribed member of the genus, in the prominent tubercles of the shell, 

 shell coloration, much smaller size, plumpness, and slenderness of 

 furca, its length to breadth being about as 32 to 1, while in S. paxH<ti<<i 

 the ratio is about as 23 to 1. 



Observations. — This form is not especially free swimming, and is 

 usually pretty well confined to the debris and algae of the bottom. 

 It was found in company with many Cladocera, Hydra, Hydrachnids, 

 Cyprais monacha, Cypris fuscata, Cypria dentifera, etc. A num- 

 ber of cultures were made in battery jars, also in Syracuse watch 

 glasses. Those made in the watch glasses were started April 26, 

 1906, and kept in good shape until the latter part of May of the 

 same year in an attempt to get their eggs, but none noted. 



()< ■< ui^rence. — The specimens examined were collected from various 

 localities southeast of Chicago, Illinois. They were first noted in 

 an aquarium started January 28, 1903, with debris, etc., taken through 

 the ice from a shallow T permanent pond, situated near the water- 

 works station in the south end of Jackson Park. Chicago. They 

 were continuously noted in collections made in April and May from 



