24 



lias collected it under similar conditions on the shores of Karmo, and 

 several specimens are preserved in our university Museum, brought home by 

 the late professor Kaseh, probably from the district of Christiansurid. It is a 

 very active animal, being enabled to jump away by very quick and abrupt 

 leaps, so that it is only to be caught with great difficulty. 



Dixtfilniticm. - Atlantic coast of Europe: Denmark, Br'tish Islands. 

 France ; Mediterranean ; coast of Algiers (Chevreux) ; Azores (Barrois). 



Gen. 2. Orchestia, Leach, 1814. 



Body more slender and compressed than in Talitrus. First pair of 

 eoxal plates rather small; 5th pair almost as deep as the preceding and deeply 

 bilobed. Cephalon, antennse and oral parts almost exactly as in Talitrus. 

 Anterior gnathopoda small, subcheliform in both sexes, the propodos having 

 a distinctly defined palmar border. Posterior gnathopoda very dissimilar in 

 the two sexes, in female about as in Talitrus, in male very strongly developed, 

 terminating with a very large and powerful subcheliform hand. Pereiopoda 

 about as in Talitrus, but the last pair somewhat more elongated and often 

 peculiarly modified in the male. Branchial lamellae small. Incubatory lamella 3 

 of the same structure as in Talitrus, but considerably larger. Appendages 

 of metasome and urosome almost as in the latter genus. 



Reiudrkx. This genus is chiefly distinguished from Tfilitru* by the 

 structure of the gnathopoda, the 1st pair of which, instead of being simple, 

 are subcheliform in both sexes, whereas the 2nd pair show a very unequal 

 development in the two sexes. The genus is widely distributed and comprises 

 numerous species, which in their habits closely resemble the Talitri, being 

 evidently terrestrial in character. In Norway only a single species has 

 hitherto been recorded. 



2. Orchestia littorea, (Mont). 



(PI. 10). 



Cancer ( (i<innnix) Htlomtx, Montague, Linn. Trans. IX, p. 96, PI. 4, fig. 4. 



Syn : Ta lit run trij>ii<U(t)is, Kroyer, 

 Orcliestia Euclwrc, F. Mtiller. 



Body rather slender, with the back evenly rounded throughout, Oepha- 

 Inn scarcely longer than the 1st segment of the mesosome. First pair of 

 '<>\al plates triangular, much smaller than the 2nd and partly covered 

 I'y the same; f>1h pair having the anterior lobe somewhat larger than the 



