95 



Colour. Body generally very pellucid and almost colourless, in some 

 cases, however, of a dark bluish hue. 



Length of adult female 1.30 mm., of male 1.00 mm. 



Remarks. I am by no means prepared to agree with Prof. Brady in 

 regarding this form as only a variety of I), gracilis. True, it is nearly allied 

 to this species; but on a closer comparison, several well-marked differences are 

 found to exist, which seem to be fairly constant and prove this form to be in 

 reality a well-defined species. I was also long ago aware of the existence of this 

 form, and had assigned to it the provisional name D. microlobatus, on account 

 of the small size of the lateral expansions of the last pedigerous segment in 

 the female. 



Occurrence. I have met with this form occasionally in the lake Femsjo. 

 situated at the south-eastern corner of Norway, and also not unfrequently in small 

 tarns at Hammerfest and at Matsjok, Finmark. According to Mr. J. Richard, 

 it has also been found in great abundance, by Mr. Ch. Rabot in the great lake, 

 Rosvand, in Nordland. 



Distribution. Sweden (Lilljeborg), British Isles (Brady), mountain lakes 

 of the Eifel, Germany (Zacharias), Kola Peninsula (Lilljeborg), territory of Ak- 

 molinsk, Central Asia (Lepeschkin). 



Fam. 15. Temoridae. 



Characters. Body of varying form, in some cases rather short and stout, in 

 other cases comparatively slender. Cephalosome well defined from the 1st pedigerous 

 segment, front unarmed, or provided with 2 soft tentacular appendages. Last 2 

 segments of metasome confluent, or at any rate imperfectly defined. Urosome 

 consisting in female of 3, in male of 5 segments; caudal rami of different struc- 

 ture in the different genera. Anterior antennae consisting in female of 24 or 25 

 articulations; right antenna in male distinctly geniculate. Posterior antennse and 

 oral parts on the whole normal. The 4 anterior pairs of legs with the joints of 

 the inner rami more or less reduced in number. Last pair of legs in both sexes 

 simple, not natatory, without any trace of inner rami; those in male, as usual, 

 larger than in female, and prehensile. Ovisac in some cases present, but more 

 frequently wanting. 



