290 



■ 



proximal third part of the inner branch is almost one and a half as broad as the middle and bears 

 at the outer distal angle two appendages. The outer or stylamblys is styliform, 0,3 mm. long 

 and 7-times as long as thick, with a rounded tip without cincinnuli; while the stylamblys measures 

 one-third the length of the endopodite, the other appendage, the appendix masculina, is 0,64 mm. 

 ong, twice as long and reaches to the tip of the endopodite. The appendix 

 miasculina shows an uncouth shape, it seems to be formed of two joints, of which the proximal 

 is 0,54 mm. long and 0,06 mm. broad in the middle, 9-times as long as broad, and a little 

 widened distally, the distal margin oblique and two setae at the antero-internal angle ; the much 

 smaller distal joint, 0,1 mm. long and 0,06 mm. broad at base, measures but one-fifth the 

 other and bears 5 or 6 long setae on the tip and the inner margin, while the lateral margins of 

 the proximal part are glabrous. In the following pleopods of the male both the endopodite and 

 the stylamblys are as well-developed as in the 2 nd , being not or hardly reduced. 

 The 3 ld and the 4" 1 were not examined, but I come to this conclusion by the examination of 

 the 5 lh pleopod (Fig. 69//, 69/) the measurements of which are the following: exopodite long 

 1 mm. and 0,3 mm. broad, endopodite long 0,84 mm., 0,2 mm. broad in the middle, little 

 short er than the exopodite, stylamblys long 0,24 mm., 6-times as long as thick, measuring 

 still almost one-third the length of the endopodite. 



Of the 2 nd pleopod of the female (Fig. 69/') the outer branch is 1,25 mm. long and 0,35 mm. 

 broad, presenting the same form as in the male. The endopodite is 0,72 mm. long, four- 

 sevenths the length of the outer branch and reaching about to the middle of it; it is nearly 

 4-times as long as broad, shows till near the tip the same width and carries im media tel y 

 behind the middle a stylamblys which is very short, 0,14 mm. long and 0,04 mm. 

 thick, measuring only one-seventh the length of the endopodite; the stylamblys carries on 

 the rounded tip two long, feathered setae, but is for the rest glabrous and without 

 cincinnuli. Two long setae occur just behind the base of the stylamblys and six between it and 

 the apex of the endopodite, that is tipped with one long seta, while three are implanted on 

 the inner margin of the branch immediately behind the apex, for the rest the margins are 

 glabrous. Also of the female the 3 rd and 4 th pleopods were not examined, but of the 5 th the 

 endopodite is very small, the exopodite o,S mm. long and 0,26 mm. broad, the endopodite, 

 however, 0,26 mm. long and 0,12 mm. broad, measuring but one-third the length of the 

 outer branch and twice as long as broad; a stylamblys could not be observed, 

 but 5 or 6 feathered setae occur on the outer margin and the tip, while the inner margin is 

 glabrous. The endopodite, no doubt, will prove to be gradually more reduced, like 

 also the stylamblys, in the 3 rd and 4 th pleopods. 



Doflein's type was only about 10 mm. long and laden with a moderate number of 

 comparatively large eggs. 



General distri but ion: Sagami bay, Japan (Doflein). 



Aegeon (Risso) Guér.-Ménev. 



The genus Aegeon (Risso) Guér.-Ménev., as defined by Steiïbing and Alcock, is nowadays 

 represented by 11 species and 3 varieties, including the new A. Sibogae and the two new 



