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



21 



8. TYRO MARGINATA, C. BOVALLIUS, 1885. 



PI. Ill, fig. 18—33. 



Diagn. Corpus non carinatum, lateribus marginatis. Caput duplo altius quam longius, superne 

 carinatum, carinis divergentibus. Antenna' primi paris dimidio corporis breviores. Pedes 

 pereii primi et secundi parium metacarpis ante productis. Pedes quinti paris pedibus 

 sexti paris multo longiores; femur ante fortiter, post leviter serratum, articulis tribus 

 sequentibus multo brevius, spinam rectam validissimam, genu quinquies longiorem, gerens; 

 tibia carpo paullo brevior; carpus metacarpo paullo longior. Pedes septimi paris dimidio 

 longitudinis pedum quinti paris paullo breviores. Dactyli parium trium ultimorum curti, 

 validi, fortiter curvati. Segmenta uri duo ultima coalita. Pedes uri lati, partim fortiter 

 • sjerrati; rami externi primi paris parvi, secundi paris longi, angusti; tertii paris magni, 

 duas partes longitudinis pedunculi superantes. Kami interni primi et secundi parium 

 pedunculis valde longiores, rami secundi paris margine interiore excavato; rami interni 

 tertii paris pedunculos requantes. Telson minimum, rotundatum. 



The body is not carinated, the lateral parts with a distinct margo. The head is twice deeper 

 than long, keeled on the upper side, the keels divergent. The first pair of antermce are 

 shorter than half the body. The first and second pairs of pereiopoda with the metacarpi 

 produced anteriorly into sharp processes. The fifth pair are much longer than the sixth; 

 the anterior margin of the femur strongly, the posterior feebly serrated; the femur is 

 much shorter than the three following joints; the apical spine-like process is straight, very 

 strong, five times longer than the genu; the tibia is a little shorter than the carpus; the 

 carpus is a little longer than the metacarpus. The seventh pair are scarcely longer than 

 half the fifth pair. The dactyli of the last three pairs are short and robust, strongly curved. 

 The last two ural segments are coalesced. The uropoda are broad, partly strongly serrated. 

 The exterior rami of the first pair are small, those of the second pair long, narrow; those 

 of the third pair are longer than two thirds of the length of the peduncles. The interior 

 rami of the first and second pairs are much longer than the peduncles, those of the second 

 pair with the inner margin excavated; the interior rami of the third pair are as long as 

 the peduncles. The telson is very small, rounded. 



Colour. White. 



Length. (3 mm., without antennas 4 mm. 



Hab. The Mediterranean; captured at Messina by Professor W. Leohe. (S. M.). 



Syn. 1885. Tyro marginata, C. BOVALLIUS. »On some forgotten genera among the Amphipodous 



Crustacea». Bih. t. K. Vet. Ak. Handl. Bd. 10. 

 N:o 14, p. 15. 

 » » » 1887. "Systematical list of the Amphipoda Hyperiidea». Bih. 



t. K. Vet. Ak. Handl. Bd. 11. N:o 16, p. 5. 



Tyro marginata is a very well defined species, w r hich is at once distinguished from 

 its allies by the sharp metacarpal processes of the first two pairs of pereiopoda, the long 

 and strong femoral process of the fifth pair, the peculiar form of the dactyli of the last 

 three pairs, and the dilated, almost tumid joints of the same pairs of pereiopoda. 



