KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 21. N:0 5. 



1. TYRO CORNIGERA, H. MILNE EDWARDS, 1830. 



Diagll. Caput superne carinatum. Auteiuirr primi paris corpove longiores. Pedes perni primi paris 

 validi, metacarpo filitormi. Dactyli pedum tertii et quarti parium validissimi. Rami 

 externi pedum uri obsoleti. 



The head is keeled on the iipper side. The first pair of antennw are louger than tlie hodv. 

 The first pair of perewpoda are strong, with filiform metacarpus. The tliird and fourth 

 pairs with very strong dactyli. The exteriör rami of the iiropoda are obsolete. 



Hab. »The Athmtic, captiired by Mr Raynaiid». (M. E.). 



Syn. 1830. Hyperia cornigera. H. MILNE EDWARDS. — — »Extrait de Recherches pour 



servir ä Thistoire iiaturelle 

 des Crustacés ainphi- 

 podes». Ann. Se. Nat. 

 Torne 20™<', p. 387. 



Tyro » » » 1840. Histoire uaturelle des Cru- 



stacés. Torne 3'"^ p. 80. 



1) » » Spence Bate. 1862. Catal. Arapli. Crust. Brit. 



Museum, p. 308. 



» » » t'. Bov.\LLius. 1887. »Systematical list of the Am- 



phipoda Hyperiidea». Bih. 

 t. K. Sv. Vet. Ak. Haudl. 

 Bd. 11. N:o 16, p. 3. 



I have not been able to identify Tyro cornigera with any of the specimens I 

 have examined, but I think that it is closely allied to T. atlantica or 2\ (jracilis. 



H. MiLNE Edwards has already pointed out the sexual difference, mentioning the 

 long slender four-jointed second pair of antennte in the inale, and the rudimentary ones 

 in the female. The characteristic of divergent obtuse keels on the upper side of the head 

 is common to all species I know, being only raore or less distinct, and depends upon a 

 median depression caused by the strong development of the basal joints of the first pair 

 of antennai. 



Here follows an extract of the description of Milne Edwards. 



The upper side of the head is provided with two small, obtuse, divergent crests. 



The firsl pair of antennce are longer than the body; the inner mai^gins feebly ciliated. 



The second pair of antennce are rudimentary in the female; in tlie male they consist 

 ot four joints, the last two the longest. 



The first pair of jJereiojwdn are tolerably robust, the tibia and carpus are elongated, 

 the metacarpus is almost iiliform. 



