AMPHIPODA HYPERIIDEA. 
Diagn. Head free, not coalesced with the first pereional 
segment. 
Eyes mostly large, often occupying the whole surface of 
the head. 
First pair of antenn&e without secondary flagellum. 
Maxillipeds coalesced into a kind of operculum, with- 
out palps. 
Uropoda more or less laminar, forming natatory organs. 
Telson undivided. 
Family 1. TYRONIDE. 
Diagn. Head small not tumid. Eyes small. First pair 
of antenn&e straight, styliform, fixed at the anterior side of the 
head. Second pair angulated, fixed at the inferior side of the 
head. Mandibles without palp. Seventh pair of pereiopoda 
not transformed. 
Gen. 1. TYRO, H. MIiLnE-EDWARDS, 1840. 
Histoire naturelle des Crustacés. Tome 3:me, p. 80. 
1. 'T. cornigera, H. MiLnE-EDwaARrpDs, 1830.!) 
>Extrait de Recherches pour servir å V'hist. nat. des Crustacés am- 
phipodes>. Annales des Sciences nat., tome 20:me, p. 387. 
Diagn. First pair of antenne straight, longer than the body. 
Body Hyperia-like. First pair of pereiopoda strong, with slen- 
der, almost filiform metacarpus. Dactyli of third and fourth 
pairs very strong. Exterior rami of uropoda indistinct. 
Hab. Atlantic. 
') The diagnose of the species is given here because the original diag- 
nose is mixed up with generic and specific characteristics. 
