117 



Icun bestaaeude af to simple Lameller, iiden eiiliver 

 lievæbiiinn-. Fodderne hos Hunnen 12 Par, hos 

 Hannen 10 Par; den dorsale Lap af Exopoditen paa 

 de 7 forreste Par enormt udviklet, paa 9de og 10de 

 Far hos Hunnen omformet til cylindriske omboiede 

 Strenge. Æggene omgivne af en simpel Skal og 

 sammenhobede under den bagre Del af Hunnens 

 Skal til 2 kageformige Masser. Larven ved sin 

 Udklækning forsynet med et stort, fladt Rygskjold. 



Bemærkninger. — Denne Slægt er opstillet i 

 Aaret 1840 af Loven for en sydafrikansk Art, L. 

 WaMbercji. Den kort Tid efter af Liévin opstillede 

 Slægt Hedessa er identisk med Loven's Slægt. Man 

 kjender ialt 8 eller 9 for.skjellige Arter, som dog 

 ikke alle er tilstrækkeligt characteriserede. Slæg- 

 ten synes at have en meget vid geographisk Ud- 

 bi'edning, idet Repræsentanter er fundne i samtlige 

 Verdensdele. Hos os forekommer kun én Art. 



Limnetis bracliyupus, (Miill) 

 (Pl. xvin— XX). 



Lynceus brachyurus, 0. F. Muller, Entomostraca, p. 60, Tab. 



VIII, figs. 1—12. 

 Hedessa Sieboldi, Liévin, Schriften des naturf. Gesellsoh. in 



Danzig, Bd IV, Heft II, p. i. Tab. I. II. 

 Hedessa hracliyiira, Siebold, Preuss. Provincialbl. 1849, Kd. VII, 



Heft 3, p. 198. 

 Limnetis branchym-us, Grube, Archiv f. Naturgeschichte, Bd. 



XIX, p. 71, Tab. V— VII. 



Årtscharacter. — Skallen, seet fra Siden, rund- 

 agtig, næsten ligesaa hoi som lang, den største 

 Hoide forti], Rygkanten noget skråa og kun svagt 

 Iniet, de frie Kanter af Valvlerne dannende en uaf- 

 brudt Biie, Forenden meget bredere en Bagenden: 

 — seet ovenfra liredt ægformig, den største Bredde 

 bag Midten. Langs Dorsalsiden en dyb Fure, i 

 hvis Bund Valvlerne er forbundne med hinanden. 

 Hovedet hos Hunnen næsten saa langt som Truncus, 

 Dorsalkauten jevnt buet, Rostrum endende i en 

 skarpt tilspidset Fortsats, ved Basis af hvilken der 

 er to korte laterale Fremspring. Hovedet hos Han- 

 nen kortere, Rostrum tvært afkuttet, iiden nogen 

 terminal Spids. Haledelens Endeflige hos Hannen 

 betydelig mere forlængede end hos Hunnen. Iste 

 Par Fodder hos Hannen med Haanden næsten qva- 

 dratisk og bevæbnet langs Inderkanten med en Rad 

 af 9 stærke, pladeformige Tænder, Kloen leformigt 

 krummet og tilspidset i Enden, den subapicale Lap 

 temmelig smal, kloformigt indadkruramet, og borste- 

 besat alene i Spidsen. Farven mork olivengren. 

 Længden af Skallen indtil 47-' mm. 



any tentacular projection. Second pair of maxillæ 

 consisting of only two simple lamellæ, quite unarmed. 

 Twelve pairs of legs in the female, in the male lO; 

 dorsal lobe of the exopodite in the 7 foremost pairs 

 enormously developed, in the 9th and lOth pairs, in 

 the female, transformed into cylindrical cords bent 

 at the tip. Eggs surrounded by a simple shell, 

 and accumulated beneath the hinder part of the 

 female's shell, into 2 cake-like masses. The lai'va, 

 when hatched, furnished with a large, flat carapace. 

 Remarks. — This genus was established in the 

 year 184(i, by 'Loven, for a South African species, 

 L. Wahlbergi. The genus Hedessa, e.stablished a 

 short time after by Liévin is identical with Loven's 

 genus. Eight or nine diiferent species are already 

 known, not all, however, sufficiently characterised. 

 The genus seems to have a very wide geographical 

 distribution, representatives being found in all quar- 

 ters of the globe. Only one species occurs in this 

 country (Norway). 



Limnetis brachyurus, (MuU.) 



(Pl. XVIII— XX). 



Lyncetis brachyurns, O. F. Miiller, Entomostraoa, p. 69, Tab. 



VIII, figs.' 1-12. 

 Hedessa Sieboldi, Liévin, Schriften des naturf. Gesellsch. in 



. Danzig, Bd. IV, Heft II, p. 4, Tab. I, II. 

 Hedessa hrachyura, Siebold, Preuss. Provincialbl. 1849, Bd. VII, 



Heft 3, p. 198. 

 Limnetis branchyunis, Grube, Archiv f. Naturgescliichte, Bd. 



XIX, p. 71,' Tab. V— VIL 



Specific Characters. — Shell, seen from the 

 side spheroidal, almost as high as it is long, 

 the greatest height being in front; dorsal margin 

 rather oblique and only slightly arched, the free 

 edges of the valves forming an uninterrupted curve : 

 the anterior end much broader than the posterior. 

 Seen from above, the shell is broadly ovate, with 

 the greatest breadth behind the middle. Along the 

 dorsal surface, runs a deep furrow, at the bottom 

 of which the valves are connected with each other. 

 Head in the female almost as long as the trunk, 

 dorsal margin evenly curved, rostrum ending in a 

 sharply pointed projection, at the base of which 

 there are two short lateral prominences. Head in 

 the male shorter, rostrum abruptly truncated with- 

 out any terminal point. Terminal lobes of the caudal 

 part in the male considerably more produced than 

 in the female. First pair of legs in the male with 

 the hand almost square, and armed along the inner 

 margin with a row of 9 strong, lamellar den- 

 ticles; claw falciformly curved, and pointed at 

 the extremity; sub-apical lobe rather narrow, bent 

 inwards like a claw, and clothed with bristles only 



