KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 21. N:0 5. 13 



Ovitectrices arc present on the third to the sixth pairs; they are large, very thin 

 lamina?, fringed with some few distant thick hairs. 



The pleon in the male equals the length of the last four pereional segments, but in 

 the female only the length of the last three and half the fourth. The segments are equal 

 in length. The lateral parts are marked by a feeble keel, the continuation of the cpimeral 

 line on the pereion. The hinder corners are obtusely rounded. 



The pieopodn (PI. II, fig. 9) are well developed; the peduncles are robust and thick, 

 longer than the rami. The outer ramus is 8 — 9-jointed, the inner 10 — 11 -jointed. The 

 cilia? are not longer than the rami, and not pedunculated. 



The urus (PI. II, fig. 10); the second and third segments are coalesced, and as long 

 as the first, but narrower. 



The uropoda; the inner rami of all the pairs are scarcely shorter than the corresponding 

 peduncles; the exterior rami of the first and second pairs are very minute, those of the last 

 pair are distinct, finely serrated along the inner margin, shorter than half the interior ramus. 

 The first pair are minutely serrated along the outer margin and slightly but more coarsely 

 along the upper two thirds of the inner margin; the second pair are smooth along the 

 outer, and finely serrated along the inner margin. The third pair are smooth on the 

 whole inner margin and on the outer margin of the peduncle, but finely serrated along 

 the outer margin of the interior ramus. The last pair reach beyond the first pair. The 

 uropoda contain distinct glands. 



4. TYRO ATLANTICA, C. BOVALLIUS, 1885. 



PI. II, fig. 11—18. 



Diagn. Corjnis leviter carinatum. Caput paullo altius quam longius, superne carinatum, carinis 

 divergentibus. Antenna primi paris corpore paullo breviores. Pedes pereii primi paris 

 carpis haud elongatis. Pedes quinti paris pedibus sexti multo longiores; femur ante non 

 serratum, leve, post distincte serratum, articulis tribus sequentibus brevius, spin am rectam, 

 genu paullo longiorem, gerens; tibia carpo multo brevior; carpus metacarpo duplo longior. 

 Pedes septimi paris tertiam partem longitudinis pedum quinti paris superantes. Segmenta 

 uri duo ultima coalita. Pedes uri lati, minute serrati; rami extend primi et secuudi 

 parium parvi, rami externi tertii paris magni, pedunculo paullo breviores. Kami intend 

 trium parium pedunculis multo longiores. Telson anguste lingulatum, dimidium rami ex- 

 terni tertii paris haud aequans. 



The body is feebly keeled. The head is a little deeper than long, provided on the upper 

 side with two divergent keels. The first pair of antennae are a little shorter than the body. 

 The first pair of pereiopoda with the carpi not elongated. The fifth pair are much longer 

 than the sixth; the anterior mai-gin of the femur smooth, not serrated, the posterior distinctly 

 serrated; it is shorter than the three following joints together; the apical spine-like process 

 is a little longer than the genu, straight; the tibia is much shorter than the carpus; the 

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



