GAMMA.RUS LOCUSTA. 379 



Hist. 2 ser. xix. p. 144. Cat. Amph. Brit. 

 Mus. p. 266, pi. xxxvi. fig. 6. ZADDACH, 

 Syn. Crust. Pruss. Prod. p. 4. LILJEBORG, 

 Kongl. Vet. Akad. Handl. 1853, p. 448. 

 Ofvers. af Kongl. Vet. Akad. Forhandl. 1852, 

 p. 9. BURGERSDYCK, Annot. de quil Crust. 

 p. 18. BRUZELIUS, Skand. Amph. Gramm. 

 p. 52. VAN BENEDEN, Recherches sur la 

 Faune lit. de Belgique. Crustaces, p. 144. 



Gamm.ai v us Duebenii. LILJEBORG, Ofvers. af Kongl. Vet. Akad. For- 



handl. 1851, p. 22. 



Gammarus mutatus. LILJEBORG, Kongl. Vetensk. Akad. Handl. 



1853, p. 448. 



IN this species the three anterior segments of the tail 

 have the infero-posterior angle produced to a point. 

 The eyes are of a long reniform shape, and are white in 

 colour. The antennae have the peduncles strongly 

 hirsute. The superior antennae are nearly half the 

 length of the animal, and terminate in a very slender 

 flagellum; the secondary appendage is about one-third 

 the length of the primary ; in full-grown specimens it 

 consists of nine, but in younger individuals of only four 

 or five articuli. The inferior antennae are rather more 

 robust than the superior, and about one-fourth shorter ; 

 the flagellum has but few articuli. The hands are 

 small, nearly of one size, and furnished with several 

 fasciculi of hairs ; the palm of the second pair is more 

 oblique than the first. The first two pairs of walking 

 legs are short, the last three are unequal in size, the 

 middle being the longest. The first three segments of 

 the tail have the posterior margin unarmed, whilst 

 the last three are respectively furnished with three 

 fasciculi of spines, the lateral ones having about six 

 spines in each. The last pair of caudal appendages have 

 the branches subfoliaceous, and nearly of one length, 

 the inner one sometimes one-fourth or one-third smaller 

 than the outer one ; both are fringed with bundles of 



