494 REPORT ON THE ORDER STOMATOPODA—BIGELOW. vol.xvii. 



the telsou, the whole dorsal surface beset with numerous minute prickles ; 

 two large submecliau marginal spines, with minute movable tips, the 

 intermediate and lateral spines being obsolete, and the basal prolonga- 

 tion of the uropod ending in two tiattened curved spines, of which the 

 outer is the longer. 



Qcneral descripiion. — Except for the telsou, this species corresponds 

 in structure almost exactly with the well-known 0. chiragra., Latreille. 

 The telson also resembles that of the last-named species, but it has 

 striking and characteristic differences. The three central dorsal promi- 

 nences are higher than in G. chiragra, broader and more closely pressed 

 together. The vertical diameter of the telson exceeds half the hori- 

 zontal diameter, which is not the case in the other species. The basal 

 cariu^e of the submediau and intermediate marginal spines are repra- 

 sented by broad, rounded, longitudinal prominences, separated from 

 each other and from the central ones by narrow grooves. The lateral 

 marginal jiair of carinje is inconspicuous. But what is most charac- 

 teristic is that the whole dorsal surface of the telsou, except the bot- 

 tom of the grooves, is roughened by minute projecting spines. The 

 telson appears at first sight to have but a single large pair of marginal 

 spines. Closer examination, however, reveals two small teeth on each 

 side that are evidently homologous to the intermediate and lateral 

 spines of such a form as G. grajithuriis, for instance. The submediau 

 spines have a large number of minute denticles on their inner margins. 



The first antennae are short, the second joint not extending beyOnd 

 the eyes. The second antennte are nearly as long as the first pair, 

 but the anteunary scale is small, not larger than half the short cara- 

 pace. The basal prolongation of the uropod is broad and fiat and the 

 spines are curved inward. The outer one has no tooth on its inner 

 margin. The distal segment of the exopodite is about half as long 

 as the proximal one, which bears nine movable spines. 



When I published my preliminary description of this species 1 had 

 not seen Pfefier's paper (1889) iu which he describes a very similar spe- 

 cies from Zanzibar, G. spinosissimus. It is possible that the two forms 

 may prove finally to be merely varieties of a single species, but at pres- 

 ent they appear to be distinct in spite of the fiict that they disagree iu 

 very few particulars. The chief differences are in the fifth and sixth 

 abdominal somites. In our specimens there is but a single pair of cariune 

 on the fifth somite, and the sixth bears six prominences with smooth and 

 shining surfaces, the spaces between being somewliat jjubescent. Each 

 prominence or carina is tipped with a spine. The outer pair are the 

 longer, the other four are of more nearly the same length, the inter- 

 mediate pair being smaller and atrifie sliorter than the submediau pair. 

 The other form, on the contrary, has, according to Pfefifer, two pairs 

 of carinas on the fifth abdominal somite, and on the sixth there are 

 four rounded knobs, the middle pair near one another and separated 

 from the lateral by a deep furrow. The last-mentioned pair is also 



