24 



lias collected it under similar cdiKlitidiis on the sluires of Karmii, and 

 several specimens are preserved in nnr nniversity Musenm, In'onglit home by 

 the late professor "Rasch, ]irolialil\- from the district of ("hristiansnnd. It is a 

 very active animal, being enabled to jnmp away by very (|nirk and abrn]it 

 leaps, so that it is only to be canght with great difficnlty. 



Dislrihiition. — Atlantic coast of Europe: Denmark, Br'tish Islands, 

 France ; Mediterranean ; coast of Algiers (('hevreux) ; Azores (Barrois). 



Uen. 2. Orchestia, Leach, 1814. 



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

 coxal plates rather small ; 5tli pair almost as deep as the preceding and deeply 

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

 Anterior gnathopoda small, snl)cheliform 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 develojied, 

 terminating with a very large and powerful subcheliform hand. Pereioj)oda 

 about as in Taliti'us, but the last pair somewhat more elongated and often 

 ])eculiarly modified in the male. Branchial lamella^ small. Incubatory lamellff" 

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

 of metasome and urosome almost as in the latter genns. 



Memories. — This genns is chiefly distinguished from Talifruf^ by the 

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

 are subcheliform in both sexes, whereas the "ind pair show a very unequal 

 development in the two sexes. The genns is widely distributed and comjii-ises 

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

 evidently terrestrial in character. In Norway only a single s]iecies has 

 hitherto Ijcen recorded. 



2. Orchestia littorea, (Mont). 



(PI. 10). 



Cancer (Gfimmarnit) Hffomif!, Montague, Linn. Trans. IX, p. lifi, PI. 4, fig. 4. 



iSyu : TaiUrus tripwlianfi, Kroyer, 



- Orchestia Euchnre, F. Miiller. « 



Body I'ather slender, with the back evenly rounded thronglumt. Oepha- 

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

 coxal plates triangtilar, much smaller than the 2nd and partly covered 

 by the same; r)tli pair having the anterior lobe somewhat larger than the 



