Dr. A. Philippics Zoological Notices, 99 



quently orange-red or brown-red, sometimes even brown with 

 whitish transparent variously indented (gezacktem) margin, 

 so that rarely two individuals look perfectly like one another ; 

 I once found one which was very beautifully marked with a 

 white T on a dark-brown ground. The pale margin is an- 

 teriorly broader, so that the two minute distant eyes may 

 distinctly be recognised. The front feet scarcely exceed 

 the length of the body ; the posterior ones are nearly twice 

 as long. The four coxae are close to each other on every 

 side, and the anterior ones even touch in the central line. 

 (See PL IV. fig. 5.) Between the coxae I find two small points, 

 of the importance of which I am not able to form an opinion. 

 Of the following joints the first are the shortest, the last the 

 longest ; in gradual progression they are all nearly cylindrical ; 

 nevertheless the femur seems to be excavated above, the 

 tibia slightly below. All the joints, with the exception of the 

 last, are beset on the under side, at the extremity, and like- 

 wise in the centre, with bristles. The last is perfectly bare, 

 at the extremity obliquely truncated above, and bears two 

 hooked claws curved under a rather acute angle. Upon the 

 under side of the body there is an annular pointed lamella 

 which surrounds the fissure of the generative organs, fig. 5.f 

 as in Diplodonta and At ax. Of the cibarian organs I have 

 only been able to distinguish the two palpi. These are nearly 

 half as long as the anterior feet, filiform, and quinquarticu- 

 lated. The first joint is very short; the second and third 

 thick and cylindrical ; the fourth the longest of all, likewise 

 cylindrical, but much thinner; the fifth short and acute. 

 Palpi and feet are nearly colourless, at the most yellowish. 



Of the six genera which at present constitute the division 

 of the Hydrachnae, viz. Diplodonta, Atax, Arrhenurus, Eulais, 

 Limnochares and Hydrachna, it agrees by the annular lamellae 

 surrounding the sexual apparatus and other characters, mostly 

 with the first; but differs from them; — 1 .by the four coxae being 

 close on each side ; 2. by the construction of the palpi, which 

 in Diplodonta have at the fourth joint an apex of the length of 

 the fifth ; — Atax possesses a very long fourth joint, which at the 

 extremity is somewhat excavated in order to receive in the outer 

 bend the fifth joint. The other four genera differ still more : 

 Arrhenurus and Limnochares by the very short palpi ; Eulais 

 by the palpi and the hips ; and Hydrachna by the palpi, the 

 beak, &c. It hence follows, that even disregarding the maxillae 

 not discovered by me, there are differences enough to justify 

 the establishment of a new genus, which I call Pontarachna, 

 and characterize as follows : — 



Corpus subglobosum. Oculi duo, remoti. Mandibulse . . . nullse ? 



H 2 



