200 



kins has shown, and parallel cases eonld be drawn from the 

 rest of the fanna and from the flora. If we postulate a con- 

 tinental area to account for the presence of certain land shells 

 and for the absence of others, we confront a vastly greater 

 task to account for the absence of vast groups of animals and 

 plants. 



]\[ost paleogeographers insist on a larger land area in the 

 Southern Pacific than exists at present and on an extension 

 of the northwestern portion of South America, or the western 

 coast of Central America, in a northwesterly direction. Such 

 land areas would greatly alter ocean currents and increase the 

 probabilities of "drift" reaching the Hawaiian Islands from 

 those regions. 



Prof. Pilsbry's opposition to the flotsam and jetsam method 

 of stocking islands breaks down considerably when he admits 

 such a method to stock low islands of the Pacific and in such 

 cases as TornateUlna in the Galapagos. 



After considering the evidence of the fauna and flora, and 

 of geology and hydrography, it appears to me that the theory 

 of the continental nature of the Hawaiian Archipelago is the 

 less tenable, as it raises greater problem's than it is called upon 

 to solve. Therefore in the following Review I shall consider 

 that the Islands are oceanic ; that the fauna is descended from 

 immigrants which arrived at different periods, and that the 

 Islands are of enormous antiquity, instead of the alternative 

 continental theory vhich would make our fauna the descend- 

 ants of continental type Avhich flourished in late Palaeozoic 

 or early Mesozoic times. 



Origix of the IIawatiax Aloiiixi. 



In the systematic portion of this Review it has been shown 

 that the species can hv divided into two groups. In one group, 

 Leialohae, consisting of LcidloJia and Nesodryas, the first joint 

 of the antennae is very short ; in the other, Alohae, consisting 

 of Aloha. Nesorestias, Dictyophorodelphax and Nesosydne, the 

 first joint (-f the antennae is much longer. A study of the 

 male genitalia leads to tlie conclusion that they are of inde- 

 pendent origin and foi'ui two distinct phylogenetic groups. 

 The form of the aedeagus, the styles and the mechanism for 

 coordinating their movements with that of the anal segment 

 ai'c different. 



