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7. Macrocypris minna (Baird). 



(PI. XXIV & XXV) 



Cythere minna, Baird, Britisli Entomostraca, p. 171, PI. 20, figs. 4, 4 a d. 

 Syn : Bairdia minna, G. O. Sars. 



Specific Characters. Female. Shell moderately tumid, seen laterally, of 

 a somewhat irregular oblong trigonal shape, greatest height a little in front of 

 the middle and about equal to 2 '5 of the length, dorsal margin forming a bold 

 and quite even curve sloping gradually behind to the posterior corner of the 

 shell, ventral margin nearly straight and horizontal, though exhibiting a slight 

 concavity in front of the middle, anterior extremity rounded off, posterior tapering 

 to an acuminate corner; seen dorsally or ventrally, oblong fusiform in outline, 

 greatest width in front of the middle and somewhat exceeding x /3 of the length, 

 anterior extremity obtusely pointed, posterior gradually tapered to an acute 

 point; hing-line somewhat flexuous. Valves very little pellucid, with the surface 

 smooth and polished, being almost bare, except at the anterior extremity, where 

 a fringe of extremely fine and delicate hairs may be discerned. Caudal rami 

 sublinear in form, slightly tapered distally, and somewhat curved, each carrying 

 on the tip a slender, somewhat flexuous seta, and in the middle of the doral 

 edge a bundle of very small hair-like bristles. 



Male of rather smaller size than female, but resembling it in the shape of 

 the shell. Prehensile palps of maxillipeds of moderate size and not much 

 dissimilar, propodus oval in form and armed at the end inside with 2 short 

 spines, dactylus somewhat broader on the right than on the left palp. Caudal 

 rami still more rudimentary than in female, and scarcely more than twice as 

 long as they are broad, each ramus tipped with 3 very small bristles. Copulative 

 appendages oblong triangular in outline and terminating in a thin lamella 

 rounded off at the end and somewhat bowed in front. 



Colour of shell in both sexes milk-white, limbs more or less deeply tinged 

 with chestnut-brown. 



Length of adult female amounting to about 3 millimeters; that of male 

 scarcely exceeding 2.50 mm. 



Remarks. This is by far the largest and finest of the marine Cypridae, 

 and is moreover easily recognisable by the characteristic shape of the shell 

 and its milk-white colour. It is the type of the present genus, in the restrict- 

 ion here adopted. 



Occurrence. The present Ostracod is by no means rare on the Norwegian 

 coast. I have met with it not unfrequently in many places, from the Christiania 

 Fjord up to the Lofoten islands, but always only in greater deeps, from 50 to 



