1913-] S. Kemp: Crustacea Stomatopoda of the Indo-Pacific Region. 151 



From this result various interesting speculations arise. Must we conclude (i) that 

 all the small specimens exhibiting extremes of variation die before reaching maturity, 

 or (ii) do they represent dwarf races capable of breeding and perpetuating their precise 

 type, or (iii) do they at subsequent moults lose their peculiar features and approximate 

 to the typical form ? l 



Of these alternatives the second is, I believe, very improbable, 2 though with our 

 present lack of knowledge regarding the size of sexually mature specimens, it cannot be 

 wholly disregarded. There remain the first and third ; the former implies a large nu- 

 merical preponderance of small individuals, a factor at present unproved, while the latter, 

 the theory to which I myself am inclined, can only be properly substantiated by pro- 

 longed rearing experiments demanding infinite patience and beset with many technical 

 difficulties. This theory nevertheless will acquire much probability if the two others 

 can be disproved, a task somewhat easier in performance. 



The question of the nomenclature of this varietal series in G. chiragra is one of less 

 interest. Numerous terms such as incipiens , tumidus , anancyrus, etc., have been em- 

 ployed ; but if, as I believe, it can be shown that the case is to a very large extent one of 

 continuous variation, the adults approaching a standard type while young examples 

 exhibit a much greater diversity of form, all the terms must lapse, for the application 

 of names to arbitrarily selected points in a perfectly graded series cannot be upheld, 

 nor is it clear that any limit can be set to such a process. 



In this connection I would refer to Borradaile's valuable discussion on ' Varieties 

 in Decapod Crustaceans ' 3 and in particular to the following passage in the opening 

 paragraph. — " It must, however, be borne in mind that the intermediate specimens 

 between varieties are much less numerous than those which exhibit the peculiarities 

 of the varieties in a typical development. Otherwise it is only possible to say that the 

 species exhibits considerable range of variation, but that definite varieties are not 

 established." 



With this statement I am in entire agreement. The author was doubtless un- 

 aware of the main features of the present case when, at a later date k he divided the 

 species G. chiragra into a considerable number of named varieties and the same time 

 added to the named varieties of G. glabrous. That data of value from a distributional 

 or from some other point of view are likely to accrue by a precise definition of these 

 varietal phases is not improbable, but they should be designated by the letters or 



1 In most known instances of variation the distinctions between the varietal and typical forms are more 

 readily perceptible in the adult than in the young and instances similar to that found in G. chiragra seem 

 to be exceedingly rare. The only case, of which I am aware, that presents features of an analogous nature 

 is afforded by Thalassochelys caretta. Gadow notes that in this species of turtle the number of dorsal 

 scutes varies from 16 to 24 ; in adults, however, there are as a rule only 16 and abnormalities are from four 

 to seven times as common in new-born as in mature specimens. The explanation, according to Gadow, lies 

 in the partial or complete correction of the abnormalities in the course of growth. [Gadow, Orthogenetic 

 variation in the shells of Chelonia. Willey's "Zoological Results," p. 207.] 



a There is, however, some evidence that this is the case with the form to which the name ' smithi ' 

 has been applied. 



3 Borradaile, " Fauna and Geog. of Maldives and Laccadives,' ' I, p. 193- 



