^ Ostracoda Q 



an abrupt, almost gibbous bend and sloping rather steeply behind, more slowly 

 in front; ventral margin distinctly sinuated in front of the middle and curved 

 evenly upwards behind; both extremities obtusely rounded off, the anterior 

 rather broader than the posterior, which appears somewhat produced behind; 

 seen dorsally (fig. 2) the shell is narrow fusi-form or lancet-shaped, with the 

 greatest width scarcely attaining one-third of the length; both extremities 

 equally contracted and pointed at the end. Valves rather thin, semipellucid, 

 and almost bare of hairs. Anterior antennae (fig. 3) comparatively slender, 

 with the terminal part considerably longer than the basal one and all five joints 

 of about same length; setae of this part rather slender and elongated. Posterior 

 antennae (fig. 4) with the terminal part scarcely longer than the basal one, and, 

 as in the other species of this genus, without any trace of natatory setae. Oral 

 parts (figs. 5, 6) of the usual structure. Anterior legs (fig. 7) comparatively 

 slender and elongated, with the first joint of the terminal part fully as long as 

 the other three combined. Posterior legs (fig. 8) with the penultimate joint 

 distinctly subdivided, terminal joint small but having all the three apical setae 

 well developed. Caudal rami (see fig. 9) evenly curved and much attenuated, 

 with the apical claws rather slerider and considerably exceeding half the length 

 of the ramus; dorsal seta well developed and rather remote from the apex. 

 Genital lobes (ibid) unusually large, and each sending off behind a peculiar, 

 somewhat securi-form lappet. 



Colour not yet ascertained. 



Length of adult female 1 • 35 mm. 

 ^ Male. — Unknown. 



Remarks. — In the general outward appearance this form bears some 

 resemblance to the species of the genus Cryptocandona Kaufmann. It is, how- 

 ever, a true Candona, as proved by the structure of the several appendages, and 

 may easily be distinguished from most other species of that genus by the gib- 

 bously vaulted dorsal face of the shell. The peculiar shape of the genital lobes 

 is one of the most distinctive characters of the present species. 



Occurrence. — A solitary fully adult female specimen of this species was 

 found in a sample taken by Mr. F. Johansen on Aug. 3, 1913, from a brackish 

 pond at Teller, Port Clarence, Alaska.* Another specimen, exactly agreeing 

 with the one here described had been previously picked out from a sample of 

 dried mud kindly forwarded to me from Prof. Ishikawa, and taken from a pond 

 near Tokyo, Japan. 



15. Candona parvula, n. sp. 



Plate IV, figs. 10-15. 



Specific Characters. — Female. Shell less compressed than in the pre- 

 ceding species; seen laterally (fig. 10) rather regularly oblong oval in shape and 

 nearly equally high throughout, with the height about half the length; dorsal 

 margin almost straight and horizontal in the middle and sloping somewhat 

 more steeply behind than in front; ventral margin shghtly sinuated; both 

 extremities obtusely rounded, the posterior a little broader than the anterior; 

 seen dorsally (fig. 11), regularly oblong in outline, with the greatest width some- 

 what less than the height; anterior extremity obtusely pointed, posterior a 

 little broader and more blunted. Valves only shghtly pellucid, with the surface 

 smooth and of a pearly lustre. Antennae and legs (figs. 12-14) comparatively 

 shorter and more robust than in the preceding species. _ Posterior legs (fig. 14) 

 with the penultimate joint not subdivided; shortest apical seta very small and 

 hamiform, curved at the tip. Caudal rami (fig. 15) only shghtly curved and 

 much less attenuated than in C. subgibha; apical claws rather shorter not attain- 

 ing half the length of the ramus. Genital lobes (ibid) simple, rounded off behind. 



*See pp. 3-4 in part N, of this volume. 



