794 W. T. CALMAN. 



favour) even more speedily tliiin is required by ilie " loi de 

 Delboeuf " to wliich Bouvier ri-fers. 



IJordiige also made some experiments on the regeneration 

 of the cliellpeds. lie found that sifter amputation of the 

 chelipeds of an Atya, the; regenerating litiibs had at first the 

 Ortniannia-form — that is to s;iy, the propodus showed a 

 distinct palmar portion. At the first moult after the opera- 

 tion, however, the Atya-forni was assumed, the articuhition 

 of the d.ictylus liaving shifted to the proximal end of the 

 ])ropodus. It is not clear from the account given whether 

 the chela3 were perfectly formed and movable before the first 

 moult. Bordiige regards this as a typical case of atavistic 

 regeneration (regeneration liypotypique), and he also cites a 

 case described by Fritz Miiller ('92) as showing that the 

 regenerated second pair of chelipeds in Ortmannia poti- 

 mirim have an elongated and slender carpus like that of 

 Caridina.^ 



While Bordage's results are highly interesting and sug- 

 gestive, they rest upon a very narrow basis of experimental 

 evidence. There seems to be no reason to doubt his statement 

 that young of the Atya -type were hatched from the eggs of 

 an Ortmannia female, but it is based on the result of a 

 single experiment carried out under unfavourable conditions, 

 and no figures of the young prawns are given. The supposed 

 inability of the Atya females to produce Ortmannia young 

 rests also on the negative result of a single experiment and 

 the simple statement that the two forms do not interbreed 

 deserves to be examined in greater detail. It would be of 

 interest to have further particulars as to the normal course 

 of development in the two forms, and to know whether there 

 is any trace of an Ortmannia stage in the development of the 

 Atya-form of cheliped. The phenomena of regeneration also 

 require more thorough investigation ; it is possible that, as is 



1 It may be mentioned that a comparison of Miiller's original figure 

 with the copy given in Bordage's paper does not increase onr confidence 

 in the diagrammatic drawings Avhich the latter author gives to illustrate 

 liis own observations. 



