Dr. A. Philippi’s 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 coxe 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 coxe 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 Atax. 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 Hydrachne, viz. Diplodonta, Atax, Arrhenurus, Eulais, 
Limnochares and Hydrachna, it agrees by the annular lamellze 
surrounding the sexual apparatus and other characters, mostly 
with the first; but differs from them ;—1.by the four coxe 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 ;—Az¢az 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 maxillz 
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. Mandibule ... nulle? 
H 2 
