200 



outwards, the 2 seta? of the outer edge rather slender and remote from the apex. 

 Anterior antenna; much shorter than the cephalic segment and rather thick at the 

 base, terminal part not attaining the length of the proximal one. Posterior an- 

 tenna 1 with the outer ranius exceeding half the length of the terminal joint and 

 uniarticuhite. 1st pair of h-s \ v ith the inner ranius distinctly 3-articnlate and 

 somewhat longer than the out'!'. 1 -t joint much shorter than the other 2 com- 

 bined. Natatory legs rather strongly built, with the first 2 joints of the outer 

 ranius considerably thickened and densely spinulose, spines of outer edge very 

 coarse. Last pair of legs rather large, with very long and slender marginal setse, 

 distal joint narrow oblong, tapered towards the end and fringed with 5 seta-, 

 inner expansion of proximal joint narrow lingiiiform. extending somewhat be\ond 

 the middle of the distal joint, marginal seta' i> in number. 



Mnli' considerably smaller than female and of more slender form of body. 

 Caudal rami rather unlike those in female and of quite normal appearance. Legs 

 of 3rd pair with the spine of the middle joint of the outer ranius exceedingly 

 strong and detlexed ; inner ramus 3-articulate. with the middle joint produced 

 inside to a slender delle\ed stylet, last joint oblong oval in form, tipped with 2 

 unequal seta.-. Last pair of legs rather small, with the inner expansion of prox- 

 imal joint very slight and only provided with 2 denticulated spines. 



< 'olour whitish grey. 



Length of adult female 0.62 mm. 



/.' i>nnkx. This form was described (but not figured) by the present au- 

 thor as early as the year lsi>2 as a species of the genus Canthocamptus. It was 

 subsequently observed by Prof. Brady, who regarded it as new, and described it 

 in his well-known Monograph as the type of the genus Attlii't/rl/n. under the name 

 of .1. sjtiiitisn. The form recorded by the same author at a later date as Pur<<- 

 liirlniliti.-- iiti'riitix, I am unable to distinguish from the present species. The 

 peculiar shape of the caudal rami in the female will suffice at once to distin- 

 guish this species from any of the other forms of Alllifi/rlln. 



Occurrence. \ ha\e only met with this form in larger lakes, on a muddy 

 bottom at a depth of some |r\\ fatlioiiis. It \\as lirst observed in two lakes near 

 < 'In '1st lama, SogDBVand and .Maridalsvand, and 1 have subsequently also found it 

 in our largest lake. .Mjosen. as also in some other lakes in the southern part of 

 the country. It moves rather slovvlv. and more frequently keeps to the bottom, 

 tuistm'j its very flexible body between the loo.se mud. into which it is also en- 

 abled to bury itself \\ith great dexterity. 



Distribution. Sweden (Lilljeborg), British Ulesi r.rady), Germany (Schmeil), 



Holland (v. Urn-men). 



