212 Miscellanbous. 



reservoirs were carried to a certain heiglit by upheavals, which 

 lowered the temperature of their surface. lu the course of these 

 events the marine fauna disappeared, with the exception of a few 

 fishes and Crustacea less sensitive than their fellows to the action of 

 fresh water. 



Prof. Heller has carefully investigated the marine forms inhabit- 

 ing the Italian lakes. He confirms and extends most of the disco- 

 veries of M. von Martens, at the same time rectifying some of them. 

 He shows that Fahcmon lacnstris is a species very widely diffused 

 in the fresh waters of the Mediterranean basin. He cites it in the 

 lake of Albano, in the ditches of the terra Jirma in the neighbour- 

 hood of Venice, in the marshes round Pavia, in the lake Trasimenc, 

 in that of Garda, in the brooks of Dalmatia, in Corfu, in the lake of 

 Albufera in Spain, and, finally, in Egypt. But this species is not 

 peculiar to the fresh waters ; it still exists in the North Sea and the 

 Baltic. M. Heller, in fact, recognizes in it the species introduced 

 into science under the names of P. vurians and P. antennarins. It 

 appears, however, to be wanting in the Mediterranean. M. Mihie- 

 Edwards certainly mentions it, in his ' Histoire NatureUe des Crus- 

 taces,' as occurring in the Adriatic; but the author himself has 

 found this statement to be erroneous, the specimen in the Paris 

 Museum having really been derived from Lake Trasimene. The 

 crustacean in question is distinguished from all the Palaimons by 

 the want of a palpus on the mandibles, by which it ai:)proaches the 

 genus AncMst'ia. But as other characters distinguish it from that 

 genus, M. HeUcr proposes for it the new generic name of Palcemo- 

 netes (P. varians). It is probable that this Pala'monetes existed at 

 a prehistoric period m the Adriatic and Mediterranean, as at pre- 

 sent in the bays of the North Sea, in places where the water was 

 comparatively not very salt. Subsequently, after the transformation 

 of the bays into lakes, the species gradually accommodated itself to 

 the fresh water, although without attaining its original size. In 

 fact the freshwater individuals are always smaller than the marine. 

 A similar lot may be reserved in the future for another crustacean 

 of the Adriatic. Nephrops norvegiats, which is so common in the 

 northern seiis, occurs here and there in the Mediterranean and the 

 Adriatic. In the Gulf of Qiiarnero, however, it exists in considera- 

 ble (juautity. If this gulf should one day be converted into a lake 

 by an upheaval, this animal would, no doubt, in time become a true 

 freshwater crustacean, whilst its congeners would still live in the 

 northern seas. 



TheJjylmsa JluvlatiUs is not entirely confined to the lakes of Albano 

 and Ncmi ; it occurs also in the south of Italy, in Greece, in Cyprus, 

 in the Crimea, in Syria, and in Egypt. As regards the H^pluvroma 

 of the Pontine Marshes, it presents the greatest resemblance to a 

 s])ocies (*S'. gramdatum) inhabiting the Adriatic and ^Mediterranean, 

 although they cannot be completely identified. 



Lastly, M. IleUcr describes two new freshwater Crustacea of ma- 

 rine forms. The first is an Amphipod {(laDiniarns Veneris) found 

 by M. Kotschy in the Well of Venus, near Hierokiiios, in Cyprus, at 



