by Dr. Ortmann in his work on the Decapod Crustacea of the Strassburg Museum, p. 463. The 

 examination of these specimens proved indeed that Pas. Sivado is different from Pas. propinqua. 



The chief differences are presented by the abdomen. In Pas. Sivado the carapace measures 

 about half the length of the abdomen without the telson, while in Pas. propinqua the abdomen 

 without the telson is almost 3-times as long as the carapace. In one of the 3 specimens 

 the carapace is 1 7^/4 mm. long, the abdomen 45 mm. and 38 mm. without the telson, in 

 another specimen the carapace is i 7Yj mm. long, the abdomen without the telson which is 

 broken, 39 mm., and in the third these numbers are 16''/^ mm., 44 mm. and 38 mm. In Pas. 

 Sivado the abdominal segments are n o t carinate, even the upper border of the 6"' segment, 

 though much compressed, is blunt, not carinate, and the terminal spine runs horizontally 

 backward, whereas in Pas. propinqua this segment is sharply carinate and the terminal spine 

 regularly curved downward. The posterior margin of the telson (PI. I, Fig. 2a) is slightly 

 convex, regularly rounded, presenting another form than in Pas. propinqua and the 

 telson is less deeply grooved. The front (PI. I, Fig. 2) is in Pas. Sivado also triangular, 

 but comparatively broader, less prominent and projects distinctly less forward 

 than the outer orbital angles, that are angular though obtuse, while in l^as. propinqua they 

 are rounded and project nearly as far forward as the front. 



In his valuable work on "The Decapoda Natantia of the Coasts of Ireland, Dublin igio", 

 Stanley Kemp, however, has pointed out, p. 37, that the abdominal somites of Pas. Sivado are 

 not dorsally carinate and that the telson is truncate at apex. A detailed, exhaustive description 

 of Pas. Sivado (Risso) does, however, as far as I know, not yet exist. 



2. Pasiphcra sp. a. PI. I, Fig. 3 — 3 (;. 



Stat. 148. August ID. o°i7'.6S., I29°I4'.5E. Halmaheira Sea. Plankton, i young specimen. 



I do not succeed in determining with certainty this specimen, but nevertheless wish to 

 describe it. The carapace, measured in the middle line, is 4,6 mm. long, the abdomen 9,7 mm., 

 the entire length 14,3 mm.: the carapace is thus half as long as the abdomen. Front (Pig. 3) 

 broadly rounded, little prominent, projecting much less forward than the rounded, orbital angles; 

 no antennular prominence, anterolateral sinuses wanting or hardly indicated, branchiostegal spine 

 small. Carapace compressed, though not carinate dorsally. Postfrontal spine slender, obliquely- 

 ascendant, procurved, acuminate. 



Abdomen not carinate, the terga of the 1*' — 5'*^ somite rounded; the 6"* somite, which 

 is twice as long as the 5''^ and twice as long as wide, is very much compressed, but the upper 

 border is blunt, not carinate, and ends in a small acute tooth. Telson (Fig. 3^) measuring two- 

 thirds the length of the 6'*^ somite, deeply furrowed along its whole length to near the base; 

 posterior margin truncate, very slightly convex, like in Pas. Sivado (Risso), and armed with 

 4 spinules at either side of the middle line. Endopodite of caudal swimmeret projecting beyond 

 the telson by about one-fifth of its length, exopodite by two fifths. 



The antennular peduncle reaches .si.x-sevenths of the way along the distance between the 

 orbital margin and the extremity of the antennal scale; basal article one-third longer than the 



SIROGA-EXPEDITIE XXXlXa'. 2 



