two-sevenths or a little more than one-fourth of the propodus, are 3-times as long as broad 

 at their base, — the length of the dactyli being the straight distance between the tip of the 

 ventral hook and the proximal end of their anterior margin — , as well in the specimens from 

 Stat. 273 as in those from Atjeh and from the Maldive Archipelago; sometimes as in the 

 specimen taken at Stat. 33 the proportion between length and width becomes 2,8 and in the 

 adult female from Stat. 144 the dactyli are comparatively broader at their base, the proportion 

 between length and width being here 2,5. According to Coutière (1. c. 1905), in that species 

 which was regarded by him as the true Syn. neomeris, the thickness of the dorsal hook should 

 be no more than one-third that of the ventral and the former should be half as long as the 

 latter; in the variety streptodactylus the dorsal hook should measure at least two-thirds the 

 length of the ventral, which should be only twice as thick as the dorsal hook. All the specimens 

 collected by the "Siboga" now present the characters of this variety streptodactylus, but the 

 ventral hook shows a stouter shape than in Fig. 1' of Coutière's paper: in the "Siboga" 

 specimens the conical ventral hook is namely 2,5-times, in the adult female from Stat. 144 even 

 only twice as long as thick at its base, but in Fig. i' it appears 3,6-times as long as thick. 

 The ventral hook, in the "Siboga" specimens, agrees with Fig. 1, but this figure is probably in- 

 accurate, for the ventral hook appears here only twice as thick at its base as the other, whereas, 

 after the description, it should be 3-times as thick as the dorsal hook. I wish to add that the 

 specimens from the Maldive Archipelago, kindly sent me by Coutière, fully accord with those 

 collected by the "Siboga" as regards the shape of these dactyli, the ventral hook, however, 

 appears comparatively a little less thick, though being not yet 3-times as long as thick. 



Table A. 



N" 6. 

 2,6 



Proportion between length of telson and width of posterior margin . 

 Proportion between the greatest width and that of posterior margin . 

 Proportion between length of telson and the distance of the anterior 



pair of spinules from the posterior margin 1,97 1,07 i,6S 1,8 1,81 1,9 



Proportion between the distances of the tw'o pairs of spinules from 



the posterior margin i,ö 1,04 1,53 1,01 1,74 1,75 



N° 1 female with eggs from the Maldive Archipelago ; N u 2 specimen from Atjeh, 

 described by me in 1897 as Alpheus neomeris. (Private Collection); N u 3 adult egg-bearing female 

 from Stat. 144; N IJ 4 female with eggs from Stat. 273; N° 5 female with eggs from Stat. 310; 

 N° 6 young specimen from Stat. 315. 



Table B, 

 indicating the proportion between the length of the meri, carpi and propodi of the third and 

 fourth legs. 



Merus 



Carpus 



Propodus 



Merus 



Carpus 



Propodus 



of the third legs 



of the fourth legs 



N'o 1. 



2,73 

 1 



2,69 



2,6 



I 



2,71 



NO 9. 



2,7 



I 

 2,6 



2,4 

 I 



2,5 



97 



SIBOGA-EXl'EDITIE XXXIXrt '. 



