Family ALPHEIDAE. 



II. Ogy rides Sibogae (de Man). PI. II, Mg. 8 — 8_^. 



Ogyris Sibogae J. G. de Man, Siboga E.xp., Monogr. 39^', Family Alpheidae, 1911 (text) 

 p. 135, 1915 (plates). PI. I, Fig. i — \li. 



7 specimens, 3 of which are provided with eggs, collected by the Siboga expedition at Ambon 

 at a depth of 54 m. 



Among the characters by which O. striaticauda Kemp of the Chilka Lake is distinguished, 

 S'lANLEY Kemp (in: Mem. Indian Mus. Vol. V, 1915, p. 288) adduces the existence on the 

 ventral surface of the telson of "four oblique ridges, the three anterior ones placed close 

 together, the other rather more distant" and the specific name is apparently derived from this 

 character. The examination of the present specimens of O. Sibogae now proved at once that 

 these ridges occur also in this species; the three anterior ones are placed exactly like in the 

 species of the Chilka Lake, but the fourth or posterior was not observed (PI. II, Fig. 8). 



The type specimen on which this species was founded by me in 19 10 and which was 

 captured in the Sulu-Sea at a depth of 535 meter, was 18 mm. long; the present specimens, 

 though apparently adult, because they are ova-bearing, are of a smaller size, about 1 3 or 

 14 mm. long from tip of rostrum to tip of telson. They fully agree with the description of 

 191 I, but the eye-peduncles are not shorter, but as long or, in the ova-bearing females, 

 even a trifle longer than the carpocerite, reaching by half the cornea beyond it, a difference 

 perhaps owing to their smaller size. 



In 4 specimens, one of which is provided with eggs, the carapace is armed anteriorly 

 with three spiniform teeth, in the three others with four as in the type; in the egg-bearing 

 female, the peraeopods of which have been figured, the 3'^'^ or posterior spine is a little farther 

 distant from the 2"'' as the 2"'' from the i*', in another ova-bearing female the 2"'' spine is 

 placed a little nearer to the posterior than to the anterior. 



Figure '6 b represents the scaphocerite of one of the egg-bearing females, it shows a 

 different form from that of O. striaticauda^ the lamella being in the latter species truncate 

 distally, which is not the case in O. Sibogae. ( )f this female the five peraeopods are figured, 

 2'/2-tinies more strongly magnified than in the Siboga Monograph. The measurements taken 



