88 
structure of this carapace presents the following appearance: the ribs 
are strongly marked and are somewhat prominent, the lower edge 
being beaded or ornamented with a line of raised round dots of a 
rather regular figure. The surface between the ribs is slightly con- 
cave, and is marked very distinctly with numerous raised dots or 
punctations of a rather irregular form and size. 
Hab. Strasbourg, Hermann. Toulouse, Joly. Oran, M. Bravais. 
Algeria, Lucas. Regency of Tunis, Mr. Frazer. Brit. Mus. 
That this is the Daphnia gigas of Hermann I think there is no 
doubt, and quite different from the Limnadia Hermanni of Bron- 
gniart. The body of the Limnadia is entirely enclosed within a cara- 
pace, regularly oval, transparent, and of a whitish colour. That of 
the Daphnia gigas, according to Hermann, is enclosed within a cara- 
pace of the colour of amber, horny, transparent, oval, with the back 
gibbous, keeled, and edged with brown. The carapace of the Lim- 
nadia is smooth, or offermg only two or three zones parallel to its 
free edge. That of the Daphnia gigas has 7 rings or parallel zones 
on the two lower thirds of its body, and to judge from the figure 
given by Hermann, has several more on the upper portion. In struc- 
ture and form it thus agrees with the characters of the genus Estheria, 
and appears to me to be perfectly identical with the Isawra Cycla- 
doides of Joly. 
Sp. 2. Esrueria Metirtensis, Nobis. (Pl. XI. f. 2, 2a, 26, 2c.) 
Carapace-valves of an elongated oval form, considerably narrower 
at the posterior than the anterior extremity ; of a light horny colour, 
and semitransparent. Anterior extremity rounded; the beaks si- 
tuate near that extremity and prominent, causing that part of the 
shell to be much more convex than any other portion. Ribs some- 
what prominent, the surface between them slightly concave and com- 
pletely covered with numerous very small dots or raised punctations 
of rather a regular figure. The lower edge of each rib is beaded like 
the last, but the dots are smaller. The shell is considerably more 
elongated than in preceding species, and the beaks are more pro- 
minent and rather nearer the anterior extremity. The colour is 
much lighter; the ribs rather less prominent, and the punctations 
on the intermediate spaces much smaller and a great deal more nu- 
merous. 
Hab. Pool of rain-water at Malta, Rev. Mr. Hennah. Brit. Mus. 
Sp. 3. Esruertia porita, Nobis. (Pl. XI. f. 3, 3a, 34, 3c.) 
Carapace-valves obovate, resembling in form the shell of a Pisidium. 
Anterior extremity somewhat broader than posterior, much more 
convex and gaping. Beaks prominently elevated, and situated near 
the anterior extremity. The shell is of a light yellowish horny co- 
lour internally and externally, and of a fine glossy polished appear- 
ance and finely pellucid. The ribs are numerous, about 27 in num- 
ber, elevated, and smooth. The spaces between are slightly concave, 
and are beautifully dotted with numerous small impressed punctations. 
Hab. India, Captain Boys. Brit. Mus. 
