151 



65. Limnicythere inopinata, (Baird). 



(PI. LXIX, fig. 2.) 



Cy there inopinata. Baird, British Entomostraca, p. 172, PI. XX, fig. 1, 1 a c. 

 Syn: Limnicythere incisa, Dahl. 



Specific Characters. Female. Shell, seen laterally, oval quadrangular 

 or short reniform in shape, greatest height exceeding somewhat half the length, 

 dorsal margin almost straight and horizontal, forming in front, above the eye, 

 a slight indication to an angle and joining the hind edge by an abrupt curve, 

 ventral margin deeply sinuated in the middle and rather bowed at the posterior 

 corner, both extremities broadly rounded off, the posterior a little broader than 

 the anterior; - - seen dorsally, more or less irregularly ovate in outline and 

 somewhat constricted in the middle, anterior extremity narrowly pointed, posterior 

 more obtuse. Valves in most cases (but not always) provided with 2 very con- 

 spicuous obtuse protuberances, best seen in the dorsal aspect of the shell, the 

 one occurring a little behind the middle and near the ventral face, the other, 

 somewhat larger, placed more behind and more approximate to the dorsal face; 

 anterior and posterior edges finely denticulated, the denticles being rather more 

 conspicuous on the hind edge; marginal zone rather broad and crossed by 

 scattered striae. Structure of the several appendages very like that in the 

 preceding species. Caudal rami however somewhat different, being conical 

 in shape and directed more forwards, with the apical bristle much prolonged. 

 Genital lobes very small, reniform in shape. 



Colour of shell whitish pellucid, with a slight bluish or yellowish tinge. 



Length of adult female 0.62 mm. 



Male unknown. 



Remarks. This form was described and figured as early as the year 

 1850 by Baird as a species of Cythere, and may properly be regarded as the 

 type of the present genus. It is of smaller size than the preceding species, 

 and moreover easily distinguished by the shorter and more regularly quadran- 

 gular shape of the shell, the distinctly denticulated posterior edge of the valves, 

 and in most cases also by the very conspicuous lateral protuberances, which 

 give to the shell a rather irregular appearence. These protuberances are 

 however in some cases much reduced or may even be quite absent, and this 

 has led to the establishment of a spurious species, viz. L. incisa, Dahl. 



Occurrence. I have taken this species occasionally in 2 small tarns near 

 Christiania, and moreover rather abundantly in a grassy swamp at Tj0t0, on 

 the Nordland coast. The specimens taken in the neigbourhood of Christiania 



