170 



Ortmann in his revisiun of the genus Leander, in : Zoolog. 

 Jahrb., Abtli. f. Syst. Bd. V, 1890, p. 514 makes also use of this 

 character for distinguishing both species. ïhe study of the nume- 

 rous specimens at my disposal now proved at once tJiat this 

 character is not consistent and does not hold good. In all the spe- 

 cimens, except the two from Rovigno, the shorter ramus appears 

 distinctly shorter than the peduncle, measured from the orbital 

 margin ; in the larger female from Rovigno the peduncle is but 

 0,5 mm. longer than the shorter ramus and in the other female 

 from the same locality both are of equal length. In 12 of 28 

 adult specimens examined the shorter ramus proved to be 0,5 

 to 2,5 mm., usually 1 mm., shorter than the rostrum, in 8 it 

 reached just to the apex and in 8 it reached 1,5 to 2,5 mm. 

 beyond the rostrum ; in the young individuals, however, from the 

 Straits of Calais the shorter ramus projects invariably 1 to 2 mm. 

 beyond apex of rostrum, in the young specimens from Brixham 

 even 2,5 to 3,5 mm. and in the specimens from Port Said that 

 are 70 mm. long, 2 to 2,5 mm., so that in these young indivi- 

 duals the shorter ramus extends for two-fifths to three-quarters 

 of its length beyond the apex. According to Heller the shorter 

 ramus should be fused to the longer for one-third, according to 

 S. Kemp for about one-quarter its length: in 13 out of 30 adidt 

 specimens it proved to be coalesced only for one-fifth, in 8 for 

 somewhat more than one-fifth^ and in 9 for one-quarter its length^ 

 in the young specimens also for one-quarter, rarely for a little more. 



The mandibular palp (S. Kemp, l. c. fig. \h) is three-jointed 

 and presents exactly the same form in the specimens from the 

 English Channel as in the females from Rovigno and as in the 

 specimens from Port Said. In an adult female from the English 

 Channel (Fig. 4a) the 1** or basal joint is 0,7 mm. long, the 

 2d 0,6 mm. long and 0,22 mm. thick in the middle, 2,7-times 

 as long as thick, the 3^ joint 1,1 mm. long and 5-times as long 

 as thick at base. In the smaller ova-bearing female from Rovigno 

 the basal joint (Fig. 4b) is 0,8 mm. long, the 2^ 0,6 mm. long 

 and 0,24 mm. thick, 2, 5-times as long as thick, the 3'! joint 



