112 Bybüs 



below the prominent posterior angle. Pleon segment 3, postero-lateral 

 angles obtusely rounded. Corneal lenses 4 or none. Mandibular palp with 

 2^ Joint narrow, 3*^ uarrow and rather short. Peraeopods 3 and 4, 2*^ Joint 

 rather broad, its front edge moderately curved, ö^^ Joint carrying several 

 transversa rows of spines. Peraeopod 5 (Fig. 27), 2'^ Joint strongly produced, 

 the long bind margiu nearly straigbt, inner and lower margins of the 

 squarely descending lobe ' carrying a dense fringe of plumose setae; 3*^ Joint 

 shorter than 4*^, 4*'i and 5*^ rather wide, 6*^^ sublinear, 7^^ spiniform. üropod 3 

 scarcely reaching beyond the others, rami narrowly lanceolate, not setose 

 in o, confronted edges more or less serrate. Telson short and broad, not 

 very deeply cleft. Two pairs of hepato-pancreatic caeca. 



10 sjjecies. 



Synopsis of species: 



I Gleft of telson minute — ^ 2. 



\ Cleft of telson not minute — 5. 



/ Antenna 2, ultimate joiut of peduncle longer tlian 



) penultimate 1. B. erythrops . . p. 112 



I Antenna 2, ultimate Joint of peduncle not longer 

 than penultimate — 3. 



j Corneal lenses wanting 2. B. abyssi . . . . p. 113 



I Corneal lenses not wanting — 4. 

 Antenna 2, ultimate Joint of peduncle shorter than 

 penultimate: peraeopods 1 and 2, 6tli Joint much 



longer than öth 8. B. gaimardii . . p. 113 



Antenna 2, ultimate Joint of peduncle equal to 

 penultimate; peraeopods 1 and 2, 6th Joint not 



much longer than 5tli . . . • 4. B. longicornis . . p. 113 



. Antenna 1 reaching well beyond peduncle of 

 ) antenna 2 — 6. 



I Antenna 1 reaching scarcely or not beyond 

 ' peduncle of antenna 2 — 8. 



J Antenna 1 not very long 5. B. afflnis . . . . p. 114 



) Antenna l very long — 7. 



I Corneal lenses absent 6. B. crassieornis . p. 114 



) Corneal lenses present 7. B. guernei . . . p. 114 



) Corneal lenses absent 8. B. serrata . . . p. 114 



) Corneal lenses present — 9.' 



I Branchial vesicles and peraeopod 2 of normal length 9. B. kallarthra . . p. 115 

 9 I Branchial vesicles and peraeopod 2 of abnormal 



I length 10. B. lepta ..... p. 115 



1. B. erythrops 0. Sars 1882 B. e., G. O. Sars in: Forh. Selsk. Christian., 

 nr. 18 p. 109 t. 6 f. 3, 3a ! 1891 B. e., G. O. Sars, Crust. Norway, v. 1 p. 187 t. 65 f. 3 | 

 1893 Ampelisca gaimardii (part.), A. DellaValle in: F. Fl. Neapel, i". 20 p. 472. 



Corneal lenses very small, lower pair removed fi'om lov?er corners of 

 front, pigment bright red. Antenna 1 little shorter than antenna 2, peduncle 

 reaching considerably beyond end of penultimate Joint of peduncle of antenna 2, 

 flagellum in o 3o-jointed, more than twice as long as peduncle; ultimate Joint of 

 peduncle of antenna 2 notably longer than penultimate. Peraeopod 5, 2^ Joint 

 produced below the 4*^*^, its front and lower edges in a continuous curve, 5*^ Joint 

 as long as 3* and 4*^ combined, a little longer than the 6*^. üropod 3 with 

 rami very slightly' serrate on the confronted edges. Telson almost Square, 



