Canon A. M. Norman on British Amphipoda. 203 



Genus 15. Tryphosa, Boeck. 

 = Orchemenella, G. O. Sars. 



34. Tryphosa nana (Kroyer). 



1846. Anonyx nanus, Kroyer, Naturhist. Tidsskr., 2 Raekkes, vol. ii. 



p. .30 ; Voyage en Scand. &c. pi. xvii. fig. 2. 

 1876. Tn/phosa nana, Boeck, (lliS) p. 181. 

 1882. Tryphosa ciliata, G. O. Sars, (102) p. 81, pi. iii. fig. 4. 

 1888. Tryphosa ciliata, A. O. Walker, Proc. Biol. Soc. Liverpool, 



vol. ii. p. 172, pi. xiii. figs. 1-4. 

 1891. Orchemenella ciliata, G. 0. Sars, (142) p. 69, pi. xxv. fig. 2. 

 1893. Tryphosa nana, J. Bonnier, " Les Aniphipodes du Boulonnais, 



III.," Bull. Sci. France et Belgique, vol. xxiv. p. 191, pi. vi. figs. 1-9. 

 1895. Orchemenella nana, G. O. Sars, (142) Appendix, p. 683. 



Hob. Shetland; Durham coast {A. M. N.) ; Isle of 

 Cumbrae (D. R.) ; Polpeiro, Cornwall (Laughrin) ; Firth of 

 Forth (T. S.) ; ' Porcupine,' 1869, off W. Ireland, 40 fathoms : 

 Mus. Nor. 70-80 miles off Spurn Head, near Hull (T. S.) ; 

 Isle of Man ; North Wales ; Valentia Harbour and Bray- 

 Head, Ireland {A. 0. W.). 



Distrih. South Norway [G. 0. Sars) ; Denmark {Copen- 

 hagen Museuni) : Mus. Nor. Jsedaren, south coast of Norway 

 (6^. 0. Sars) ; west coast of France [Chevreux) . 



My friend the late Dr. D. Robertson wrote of this species 

 in his " Second Contribution " : — " This seems to be one of 

 the sea-scavengers. A fisherman brought to me portions of 

 the crab Lithodes maia from his bait-creel, and every part of 

 it was crowded with this species clustered on the top of each 

 other. All the flesh was as perfectly cleaned off the body, 

 legs, and claws of the crab as if the parts had been bleached 

 on the shore for a twelvemonth. The number of these 

 Amphipods was quite surprising, and I had a six-ounce 

 bottle filled with them. So far as I have seen, they are all 

 of the same species. The wonder is why they remained on 

 the empty shell of the crab after having cleaned out all the 

 soft parts, unless, like the boa-constrictor after a great feast, 



they require a long time to digest it It is a curious 



fact that the Amphipoda met with at these great banquets, so 

 far as I have seen, are mostly of one species. Sometimes 

 they are exclusively Tryphosa nanoideSy or at other times 

 wholly Lafystius slurionis, Orchemenella nana { = ciliata)j or 

 Callisoma crenatum. Whether each species has its own 

 particular prey, or whether the weaker species give way to 

 the stronger, cannot easily be proved." It is not always so, 

 for I may mention that at Falmouth on a dead fish in a crab- 

 pot I found Orchomene humili's and Socarnes erythrophthalmus 



