203 



both forms are identical. As well Stimpson's Syn. biunguiculatus as Syn. brachyceros Nob. are 

 perhaps identical with Syn. prolificus (Sp. Bate) (Report Challenger Macrura, p. 556, PI. XCIX, 

 fig. 4), a species that also occurs at the Hawaiian Islands but that is insufficiently known, 

 because in the only specimen, a female, which was captured by the "Challenger", the first pair 

 of legs were missing. In fig. \c of Spence Bate's Report the third antennular article appears 

 decidedly longer than the second, just as is the case in Syn. brackycerosl 



I. Comatularum group. 



f 1. Synalpheus amboinae (Zehntner). 



Alpheus amboinae L. Zehntner, Crustacés de 1'Archipel Malais, Genève 1894, p. 202, PI. VIII, 

 fig. 23, 23 a, 23b. 



Stat. 50. April 16/18. Bay of Badjo, West coast of Flores. Depth up to 40 m. Mud, sand 



and shells, according to locality. 1 specimen of medium size. 

 Stat. 273. December 23'26. Anchorage off Pulu Jedan, East coast of Aru-islands (Pearl-banks). 



13 m. Sand and shells. 1 young specimen. 

 Stat. 282. January 15/17. 8°25'.2S., i27°i8'.4E. Anchorage between Nusa Besi and the N.E.- 



point of Timor. 27 — 54 m. Sand, coral and Lithothamnion. 1 very young specimen. 

 Stat. 303. February 2/5. Haingsisi, Samau-island. Depth up to 36 m. Lithothamnion-bottom. 



1 adult specimen, without the large cheliped. 



In the young specimen from Stat. 273 the rostrum just reaches beyond the 2 nd anten- 

 nular article and its tip as also the tips of the slightly divergent, orbital spines are a little 

 curved upward ; in the still younger specimen from Stat. 282 the rostrum reaches even to the 

 middle of the 3 rd article, but it projects straight forward, whereas the orbital spines that are 

 parallel, are also hardly curved upward. In the specimen from Stat. 50 the rostrum extends to 

 the middle and in the adult specimen from Haingsisi just beyond the middle of the 2 nd article 

 and in both rostrum and orbital spines that run parallel, project straight forward. The subacute 

 rostral carina is separated by deep grooves from the orbital hoods which are rounded above. 



The antennular peduncle accords with Zehntner's description and is as long as the 

 carpocerite; the blade of the scaphocerite extends to the middle of the 3 rd antennular article 

 and the outer margin that runs like a S, ends in a spine which is slightly curved inward and 

 which reaches for a short distance beyond the apex of the blade, extending as far forward as 

 the inner peduncle; the lower spine of the basicerite is as long as the orbital spines, but the 

 upper spine which is slightly directed upward, measures but one-third of the lower. 



In the adult male from Stat. 303 the rounded, lower margin of the first abdominal 

 pleura is produced posteriorly into an acute tooth or spine directed backward; those of the second 

 somite carry also an acute tooth at the posterior angle and the four following end in a similar, 

 pointed, acute tooth. The telson is 3,2-times as long (3,06 mm.) as its posterior margin is 

 broad (0,95 mm.) and the greatest width anteriorly is 2,5-times that of the posterior margin; 

 in Zehntner's type, that is lying before me, the proportion between the length of the telson 

 and the width of the posterior margin is 3,6 and the telson appears anteriorly a little less 

 broad, in the young specimen, finally, from Stat. 273 the length of the telson is 4,5-times that 

 of the posterior margin. The anterior pair of spinules which are of a rather large size, 



71 



