I9I3-] S. Kemp: Crustacea Stomatopoda of the Indo-Pacific Region. 163 



breadth is usually not more than 18-5 ; the majority of the specimens were specially 

 selected because they appeared broader than was customary. 



Along with this character is correlated a difference in the dactylus of the raptorial 

 claw. In G. chiragra the slender terminal portion is long and its apex is always very 

 definitely inturned. In the var. platysoma, however, the finger is much shorter and is 

 not, or is only very slightly, bent at the tip. 



In the form of the telson all the specimens of var. platysoma correspond very closely 

 with the individuals to which Manchester gave the name of acutus (1903, pi. xxiii, fig. 3). 

 The keels on the dorsal surface are narrow and the median one is not anchor-shaped and 

 does not terminate in a spine ; the lateral marginal teeth are entirely absent. Lan- 

 chester's examples are perhaps identical with those named by Wood-Mason ; but the 

 point cannot be definitely settled, for the former author does not mention the other 

 characters that separate platysoma from typical chiragra. It is rather remarkable 

 that, among normal G. chiragra in the Indian Museum, no specimen occurs with this 

 type of telson, whereas all the examples of the var. platysoma from three widely distant 

 localities, agree in possessing it. It seems possible, therefore, that this feature is 

 correlated with the other characters of the variety; but the variation in the telson is 

 so great among typical G. chiragra that it would be astonishing if the form proved 

 constant in a large series of specimens. 



The six examples retain but little trace of their original colour, but in four that are 

 better preserved than the rest there is a pair of conspicuous round black spots, placed 

 close together in the middle of the first abdominal somite. These spots seem only to 

 occur very rarely in typical G. chiragra and perhaps constitute a special feature of the 

 variety. 



The specimens are registered as follows : — 

 3j|-2 Port Blair; Andamans. G. H. Booley. 2 J 1 9 , 77—80 mm. TYPES. 



—^ Society Is. Otago Museum. 1 ? , 75 mm. 



^ Mauritius. Purchased. 2 9 , 48*5 and 70 mm. 



The examples which Manchester recorded as G. chiragra var. acutus were taken at 

 Minikoi, and those which I,enz attributed to the same form were found at Zanzibar and 

 Madagascar. 



2. Gonodactylus acutirostris, de Man. 



1898. Gonodactylus chiragra var. acutirostris, de Man, Zool. Jahrb. Syst., X, p. 695, pi. xxxviii, 



figs, yyb, c. 



1899. Gonodactylus chiragra var. acutirostris , Borradaile, in Willey's Zool. Results, p. 400. 



1903. Gonodactylus chiragra var. acutirostris, L,anchester, Faun, and Geog. Maldives and I^accadives, 



I, P- 454- 

 1907. Gonodactylus acutirostris, Borradaile, Trans. I^inn. Soc. Zool. (2), XII, p. 210. 



This species, known from a single specimen only, may perhaps prove to be merely 

 an abnormal example of G. chiragra) it is distinguished by the following features : — 



1 . The antero-lateral angles of the rostrum are acute : distinctly sharper than in 



G. chiragra. 



2. The customary pair of tubercles near the anterior margin of the telson are 



