104 



distance from them. Anterior antennae, when reflexed, reaching to about the end 

 of the anterior division of the body. Natatory legs exactly as in E. hirundoides. 

 Last pair of legs with the penultimate joint armed outside, as in E. hirundoides, 

 with 2 spines, which however are considerably shorter; outer apical spine likewise 

 shorter than in the said species ; unguiform process rather strong and extending 

 straight inwards, at a right angle with the axis of the leg. Ovisac of moderate 

 size, rounded. 



Male resembling that of E. hirundoides, but differing slightly in the 

 structure of the last pair of legs, the 2nd joint of which is less dilated; terminal 

 joint of right leg very slender, being scarcely at all dilated at the base, that of 

 left leg terminating in 2 rounded lobes. 



Colour. Body in both sexes highly pellucid and almost colourless. 



Length of adult female 1.30 mm. 



Remarks. This form was first described by Poppe as Temorella lacustrls, 

 and was subsequently recorded by Nordqvist under another specific name, viz., 

 T. intermedia. It is closely allied to E. hiftuiduides, though differing conspicuously 

 in the simple structure of the last segment of the metasome, which does not form 

 any lamellar expansions in the adult female. Moreover the delicate spikes with 

 which the anal segment and the caudal rarai in E. hirundoides are clothed, are 

 wanting here. Finally, the last pair of legs exhibit in both sexes some small 

 differences referred to in the above diagnosis. 



Occurrence. I have hitherto only found this form in a single locality, 

 viz., in the Femsjo, where some few specimens were captured It is never found 

 except in perfectly fresh water; hence the specific name proposed by Poppe. 



Distribution. Sweden (Lilljeborg), northern Germany (Poppe), Finland 

 (Nordqvist), Ladoga (idem). 



Gen. 17. HeterOCOpe, G-. 0. Sars, 1863. 



Generic Characters. Body more or less robust, with the anterior division 

 moderately vaulted above. Cephalosome somewhat expanded in the middle and 

 having above a distinct cervical depression, front quite unarmed below. Last 

 segment of metasome confluent with the preceding one, and without any lateral 

 expansions. Urosome moderately slender, genital segment in female much the 

 largest and more or less protuberant below. Caudal rarai comparatively short 



