115 



40. Eucypris crassa (O. Fr. Miiller). 



(PI. LIII, fig. 1). 



Cypris crassa, O. Fr. Miiller, Entomostraca, p. 61, PI. 6, figs. 1 & 2. 

 Syn : Cypris dromedaria, Fischer. 



Specific Characters. Female. Shell rather tumid, seen laterally, of quite 

 an unusual shape, being somewhat gibbous in front and narrowly produced 

 behind; greatest height anteriorly and about equalling half the length, dorsal 

 margin forming in front a bold gibberiform curve and sloping obliquely 

 behind, with a slight concavity above the posterior extremity, ventral margin 

 rahter deeply sinuated, anterior extremity broady rounded off, and rather 

 sharply defined above by a conspicuous depression in front of the ocular region, 

 posterior much narrower and obtusely blunted at the end; seen dorsally, 

 regularly oblong oval, greatest width in the middle and nearly attaining half 

 the length, both extremities remarkably contracted at the ends, which project 

 as sharp rostriform points. Valves rather thin, with a well-marked pellucid 

 marginal zone; inner duplicatures remarkably broad both in front and behind; 

 surface smooth and shining. Anterior antennae with the terminal part some- 

 what longer than the basal one, joints successively diminishing in size. 

 Posterior antennae with the penultimate joint almost as long as the preceding 

 one, apical claws rather slender, natatory setae not fully extending to the tips 

 of the claws. Maxillae with the masticatory lobes less attenuated than in the 

 other species, palp likewise somewhat dissimilar, its distal joint being com- 

 paratively shorter and broader. Caudal rami rather strong, with the distal 

 claw very long and slender, almost attaining the entire length of the ramus. 



Colour light greenish. 



Length of adult female amounting to 1.90 mm. 



Male unknown. 



Remarks. This is a very distinct and easily recognisable form, differing 

 conspicuously from any of the other known species in the shape of the shell, 

 as also somewhat in the structure of the maxillae, though being apparently 

 referable to the present genus. The specific name dromedaria, under which 

 it has been recorded by Fischer, alludes to the peculiar shape of the shell, 

 as seen laterally. 



Occurrence. The only place where I have hitherto met with this form, 

 is on the high-plateau of Ekeberg, near Christiania. It occurred here early in 

 the spring very abundantly in a shallow grassy swamp, which later in the 



