10 Canadian Arctic Expedition, 1913-18 



Colour, opaque whitish. 



Length of shell scarcely exceeding • 56 mm. 



Male . — Unknown . 



Remarks. — This is a very small species and could easily be taken for only 

 the young of some larger form. I have, however, found all the appendages well 

 developed, and, though no ripe ova were observed in the body cavity, I believe 

 that the specimens had arrived at their full size. 



OcctfRRENCE. — Several specimens of this small ostracod, all of about the 

 same size, were picked up from a sample taken by Mr. Fr. Johansen, May 26, 

 1918, from a pool on fields in beaver meadow. Que., near Ottawa. 



Family CYTHERIDAE 



Genus Cytherites, new genus 



Generic Characters. — Shell short, scale-like, and much compressed, 

 with the valves perfectly equal and quite unarmed; surface smooth without 

 any obvious sculpture. Antennae rather strong and built on the usual Cyther- 

 idean type. Mandibles with all the parts well developed. Maxillae, however, 

 without any distinctly defined masticatory lobes. Legs very peculiar, all pro- 

 nouncedly prehensile, terminating in a subcheliform hand. 



Remarks. — The present new genus, the chief characters of which are 

 given above, is in particular highly distinguished by the remarkable structure of 

 the legs, which is unlike that found in any other Cytherid known to me, and 

 points to quite peculiar habits of the animal. The general shape of the shell 

 differs also conspicuously from that usually met with in Cytheridae and looks 

 more similar to that in some of the Cypridae, for instance in the species of the 

 genus Cypria. After all, this genus differs so essentially from the other known 

 Cytherida, that it should more properly be regarded as the type of a particular 

 subfamily. 



16. Cytherites insignipes, n. sp. 



Plate V 



Specific Characters. — Female. Shell, seen laterally (fig. 1), of a short 

 rounded oval shape, with all the edges smoothly curved, greatest height some- 

 what behind the middle and attaining almost two-thirds of the length; dorsal 

 margin boldly arched and sloping more steeply behind than in front; ventral 

 margin scarcely at all sinuated; anterior somewhat oblique; posterior much 

 broader and obtusely blunted, with the lower corner evenly roxmded off; seen 

 dorsally (fig. 2) the shell is very narrow lanceolate in outline, with the greatest 

 width not nearly attaining one-third of the length; anterior extremity somewhat 

 more pointed than the posterior. Valves very thin, with the surface perfectly 

 smooth and almost bare of hairs, inner duplicatures apparently very narrow; 

 eyes not observed. Anterior antennae (fig. 4) moderately strong, with the two 

 joints of the basal part sharply defined and forming with each other an angular 

 bend; terminal part almost twice as long as the basal one, and composed of 

 five joints not much different in length and clothed with comparatively short, 

 simple setae; last joint very narrow, with three apical setae. Posterior antennae 

 (fig. 5) rather stout, with the penultimate joint distinctly subdivided in the 

 middle; last joint armed with two unequal claws, the posterior one being much 

 the stronger and coarsely pectinate inside; flagellum well developed, extending 

 almost to the extremity of the antenna. Anterior lip (see fig. 6) only slightly 

 bowed in front; posterior lip, as usual, strengthened by two securiform and 

 highly chitinised pieces (fig. 7). Mandibles (fig. 8) comparatively slender, 

 but well chitinised, with the extremity coarsely dentate; outermost tooth 



