295 



at least, for, in 1888, the number of known species of Alpheus (inclusive Synalpheus) was 

 much smaller than nowadays. Coutière's biunguiculatus, however, is not identical with 

 the species described by me in 1888. Instead of creating now a new name for the biunguiculatus 

 of CoutièrEj I prefer to do so for the species which I have described in 1888, especially 

 because the former has given the name to the Biunguiculatus group. No less than 47 specimens 

 were, in 188S, lying before me, all collected by the late Dr. Brock at Amboina and in the 

 Bay of Batavia: it is therefore quite noteworthy that in the "Siboga" collections this species 

 is only represented by three specimens, two of which are very young. 



One of the cotypes, described in 1888, a male, long 27 mm., from my private collection, 

 is lying before me; the female from Stat. 164 is a little younger, but Syn. Antenor attains 

 the length of 40 mm. and is one of the largest representatives of this genus. The following 

 description is taken from the aclult specimen captured at Amboina. 



Rostrum acute, 3-times longer than wide in the middle and slightly reaching beyond 

 the i st third of the visible part of the basal antennular article; lateral spines a little shorter, 

 triangular, subacute and separated from the rostrum by intervals that are narrowing backward 

 and obtuse at their base. The rostrum which is obtusely carinate above, and the lateral spines 

 are setose at their tips. 



In the young specimen, long 11,5 mm., from Stat. 154 the rostrum, 4-times as long as 

 wide in the middle, reaches to the middle of the visible part of basal antennular article. 



The antennular peduncle is slender, 6-times longer than wide, second article twice 

 as long as wide distally, only about one-sixth shorter than the visible part of basal article ; 

 third article half as long as the latter. Stylocerite slender, acuminate, slightly longer than the 

 i st third part of median article. 



In the young specimen from Stat. 154 the antennular peduncle appears a little less 

 slender, about 5-times longer than thick, the second article is one-fifth shorter than the first 

 and the stylocerite reaches to the middle of median article. 



Carpocerite very slender, 9-times (in the young specimen almost 8-times) longer than 

 wide and surpassing the antennular peduncle by two-thirds the distal article; upper angle of 

 basicerite subacute, but without a spin e, lateral spine reaching to the middle of median 

 article. Terminal spine of the scaphocerite reaching to the transverse suture on the third antennular 

 article, slender and curved outward ; the outer margin appears therefore very concave and 

 the terminal spine exceeds b y more than two-thirds i t s length the narrow, rudimentary 

 scale, that reaches to the middle of the second antennular article. 



In the young specimen the lateral spine of the basicerite is shorter than the stylocerite 

 and does not vet reach to the middle of median antennular article; the terminal spine of the 

 scaphocerite is as long as the antennular peduncle. 



The female from Stat. 164, long 26 mm., does not quite accord with the adult specimen, 

 just described. The stylocerite just exceeds the middle of the second antennular article, while 

 the lateral spine of the basicerite extends to the distal sixth part of that article and the terminal 

 spine of the scaphocerite also slightly surpasses the antennular peduncle. 



The telson is quite characteristic, because the spinules of the upper surface are farther 



163 



