85 
for 1830, M. Krynicki has described a third species belonging to the 
family, which he found in Russia. M. Audouin, in the ‘ Annales de 
la Soci¢té Entomologique’ for 1837, announced to the Society that 
he had received specimens of another species of the same family, 
found by M. Bravais, a naval officer, near Oran on the coast of Africa, 
in a little marsh of brackish water ; and in the same year M. Straus 
Durckheim published a description and good figure of a fifth species 
found by Dr. Riippell in Abyssinia. M. Guérin-Ménéville, in the 
‘Magazin Zoologique’ for the same year, 1837, has published the 
description of a sixth species brought from the Mauritius, collected 
there by M. Desjardins; and finally, M. Joly, in the ‘Annales des 
Sciences Naturelles,’ 2nd series, vol. xviii. 1443, has published an 
elaborate memoir upon a species collected by him at Toulouse. 
From a careful examination of the figures and descriptions given 
by these authors, it is evident that these animals do not belong all to 
the same genus. It is perhaps in vain now to attempt to ascertain 
the species mentioned above as described by Linneus. Hermann 
says, the animal described by him “‘is very likely to be in reality the 
Monoculus lenticularis of Linneeus;”’ and upon examining the Lin- 
nzean cabinet in the possession of the Linnean Society, I have found 
one mutilated specimen of a species belonging to this family which 
bears much resemblance to that figured by M. Hermann. As there is 
no ticket attached to the specimen, it is impossible now to decide whe- 
ther this is really the individual originally in the possession of Lin- 
nzeus ; but if it be, it confirms my opinion, derived from comparing the 
figures and descriptions of the two species given by Hermann and 
Brongniart, that the latter author is decidedly in error in considering 
them to be identical. The species found at Fontainebleau is the true 
representative of the genus Limnadia, whilst that of Strasbourg forms 
the type of another genus. This genus was indicated by Audouin 
and Straus Durckheim in the same year; the former proposing for 
the species brought by M. Bravais from Oran, the name of Cyzicus; 
and the latter for that brought by Dr. Riippell from Abyssinia, the 
generic name Estheria. From the simultaneous publication of these 
two generic names, it is difficult to decide which should stand; and 
M. Joly, apparently feeling the difficulty, has proposed a third name, 
taking as the type the species found by him at Toulouse, and calling 
it Isaura. As M. Audouin merely indicates the genus without 
giving a description of either genus or species, whilst M. Straus de- 
tails at full length both generic and specific characters, and figures 
the typical species, I propose adopting his name and retaining the 
generic name Estheria, a name originally proposed by Dr. Rippell 
himself. 
' The genus Limnadia thus at present contains two species :— 
1. Limnadia Hermanni of Ad. Brongniart. 
2. Limnadia Mauritiana of M. Guérin. 
The genus Estheria at present contains three species :— 
1, Estheria gigas, the Daphnia gigas of Hermann, identical with 
the Cyzicus Bravaisii of Audouin and the Isaura cycladoides of 
Joly. 
