i Canadian Ardtic Expedition, 1913-18 



iii the female, obtusely rounded off. Prehensile palps of maxillipeds (figs. 8, 9) 

 distinctly unequal, propodus of the left palp (fig. 9) with a deep sinus about in 

 the middle, bounded proximally by a rather prominent linguiform expansion; 

 dactylus however in both palps narrow and greatly curved. Copulative append- 

 ages (fig. 13) comparatively smaller than in the type species and less strongly 

 chitinized, differing also conspicuously in shape. Ejaculatory tubes (fig. 14) 

 comparatively short. 



Colour not yet ascertained. 



Length of adult female about 1 mm., that of male 0-90 mm. 



Remaeks. — ^The above described' form is unquestionably specifically 

 different from C, marginata, being of much smaller size and differing conspicuous- 

 ly in the shape of the shell, as seen laterally. Moreover well-marked differencies 

 are found in the prehensile palps of the maxillipeds in the male, as also in the 

 copulative appendages and the ejaculatory tubes. 



OccxTEEENCE. — Two perfect specimens only of this form, a female and. a 

 male, were picked up from a sample taken by Mr. F. Johansen, in May, 1923, 

 from pools at BiUings bridge, Ottawa, Ont. In the same sample some detached 

 valves of quite young specimens were also found. 



Group Enctprides 



Genus Cypris 0. Fr. Mueller (sens, strict.) 



2. Cypris pubera 0. Fr. Mueller 



OccuERENCE. — Of tWs large and easily recognizable Ostracod a considerable 

 number of specimens have been collected by Mr. F. Johansen, chiefly from 

 pools at Billings bridge, Ottawa, Ont., in the month of June, 1921-23. 



Genus Eucypris Vavra. 



3. Eucypris crassa (0. Fr. Mueller) 



Ogctjreence.— A few, somewhat damaged specimens of this peculiar species 

 were found in a sample taken by Mr. F. Johansen in May, 1923, from some 

 pools at Billings bridge, Ottawa, Ont. 



Genus Cypriconcha, new genus 



Generic Characters. — Shell subcompressed, reniform in shape, and 

 scarcely at all flattened ventrally. Valves sub-equal, thin, and densely hairy, 

 with the edges unarmed; inner duplicatures broad, in particular behind. Anten- 

 nae comparatively feeble, but apparently well adapted for swimming. Mandibles 

 strong, with the palp distinctly articulate and the vibratory plate well developed. 

 Maxillae with the masticatory lobes comparatively narrow, palp rather pro- 

 duced and having the distal joint cylindric in shape. Prehensile palps of maxil- 

 lipeds in male slightly unequal, both having a very conspicuous thumb-like 

 process issuing inside the propodus. Legs comparatively slender, but of normal 

 structure. Caudal rami very much prolonged, with the dorsal edge finally 

 spinulose. Copulative appendages of male of moderate size and slightly lobular 

 behind. Ejaculatory tubes large, with numerous whorls of radiating spikes. 

 Spermatic vessels confined to the posterior part of the valves. 



Remarks. — This new genus is established to include the remarkable form 

 described below and originally recorded by Forbes as a species of the genus 

 Cypris. It is, however, evidently not a genuine Cypris, in the sense now^ener- 

 ally adopted, nor can it, as believed by Turner, be: referred to the genus Herpeto- 

 cypris, as it differs essentially in the structure/of the valves, and in the posterior 

 ^.ntennae bfeing .provided with distinctly deyeldpeii, natatory setae. As it also 

 otherwise' exhibits soihe characteristic differences frorh the other genera included 



