Mr. C. Spence Bate on British Edriophthalmous Crustacea. 143 



Genus 18, Lonchomerus (mihi). 

 Like Lembos. Meros of first gnathopod produced into a long 

 spine. 



1. L. gracilis. Spine of meros of first gnathopod as long as the 

 carpus ; carpus longer than propodos. Bactylos ornate. 

 Polperro, Mr. Loughrin. Glamorgan ; Plymouth, C. S. B. 



Genus 19. Eurystheus (mihi). 



First gnathopod smaller than the second. Upper antenna 

 with secondary appendage. Telson cylindrical. 



1. E. tridentatus (mihi). Palm of second gnathopod convex, 

 furnished with three obtuse teeth. 

 Plymouth, C. S. B. Macduff, Mr. Gregor. 



Genus 20. Gammarella (mihi). 



Antennae like Gammarus, and upper with secondary appendage. 

 Last pair of pleopoda with a single branch. Telson single. 



1. G. orchestiformis. Upper antenna longer than the lower. 

 Hand of first gnathopod small ; hand of second very large 

 and oval. Caudal appendages short. 

 Polperro, Mr, Loughrin. 



Genus 21. Amathia (Rathke). 



Upper antenna with secondary appendage. The telson entire. 

 The animal Gammariform. 



1. A. carinata (Rathke). Head with a small rostrum. Centre 

 of the dorsal surface surmounted by a distinct carina com- 

 mencing at the head and terminating with the caudal 

 segments. 

 Banff, Mr. Edwards. Crimea, Rathke. 



Genus 22. Gammarus (Fabr.). 



Body compressed. Antennae long and slender, with a secondary 

 appendage to the upper. Posterior pleopoda two, branched. 

 Telson double. 



1. G. Sabinii (Leach). 



G. Moggridgii (mihi) (Ann. Nat. Hist. 1851). 



Head with a short rostrum. Dorsal surface marked with a 

 carina commencing about the fourth segment and termina- 

 ting at the caudal appendages. 



Arctic Regions, — Sabine. Banff, Mr. Edwards. Menai 

 Straits, J. Alder, Esq. Glamorgan, C. S. B. 



