109 



47. Heterocope appendiculata, G. 0. Sars. 



(PI. LXXIV). 



Heterocope fij>i>fii<1i<-til(tta, G. O. Sars. Oversigt af de indenlandske Ferskvandscopepoder. 



Chr. Vid. Selsk. Forh. 1862, p. 15. 



Specific Characters. Female. Body considerably more slender than in 

 the 2 preceding species, with the anterior division, seen dorsally, oblong in form, 

 greatest width but slightly exceeding l /- A of the length, and occurring somewhat 

 in front of the middle. Urosome exceeding half the length of the anterior division, 

 genital segment shorter than the other 2 combined, and carrying in front of the 

 genital orifice a transverse row of 8 peculiar, reflexed appendages; anal segment 

 longer than the middle one. Caudal rami about twice as long as they are broad, 

 bristle at the outer corner wanting, and replaced by a slight dentiform projection. 

 Anterior antennae very slender and elongated, reaching, when reflexed, beyond the 

 caudal rami. Last pair of legs with the terminal joint very narrow, denticles of 

 the inner edge simple, apical spine very slender. 



Male still more slender than female, and having the middle section of 

 right anterior antenna only slightly tumefied. Last pair of legs differing con- 

 spicuously from those in the 2 preceding species, right leg rather produced and 

 peculiarly contorted, having the 3 outer joints confluent into a falciform piece; 

 left leg with the thumb-like process bulbously dilated at the tip, terminal joint 

 rather narrow, with the apical spine quite short. 



Colour. Body semipellucid and generally of a light bluish green hue, 

 anterior antennae and urosome in male tinged with orange. 



Length of adult female 2.20 mm. 



Remarks. This species may at once be distinguished from the 2 pre- 

 ceding ones by its more slender form of body, the greatly elongated anterior 

 antennae, and the peculiar appendages occurring in front of the female genital 

 orifice, the latter character having given rise to the specific name. It is also 

 rather inferior in size to the other 2 Norwegian species, and exhibits a somewhat 

 different structure in the last pair of legs. 



Occurrence. In the southern part of Norway, this species is by far the 

 commonest, occurring in great abundance in almost all the larger lakes, and 

 there constituting an essential part of the food of several fresh-water fishes. 

 In the northern and western parts of the country, as also in the mountain lakes, 

 its place is taken by H. saliens, with which it agrees perfectly in habits. 



Distribution. Sweden (Lilljeborg), Finland (Nordqvist), Ladoga (idem), 

 Northern Germany (Zacharias), Russian Lapland (Richard). 



