Hutton. — On New Species of Moas. 7 



ferent type from those found at the sandhills at the mouth of 

 the Shag Eiver associated with skulls with rounded beaks. 

 This larger species of elephantopus forms the type of Lydekker's 

 genus Pachyoruis, and the genus Euryapteryx will contain 

 only the blunt-beaked species E. pondcrosa and E. gravis. I 

 find also from the Shag Point collection that the sternum of 

 Euryapteryx resembles that of Mesopteryx (or Syomis), but is 

 more robust and has no pneumatic depressions at the inner 

 anterior corners. 



An examination of the collection from Enfield has shown me 

 that rheides and casuarina are congeneric with didina, and will 

 all come into the genus Mesopteryx, distinguished by its slender 

 pointed beak and shallow temporal fossae. This leaves crassus 

 isolated; and, for the present, it must take Eeichenbach's 

 generic name of Emeus. The skeleton of Emeus is, however, 

 very imperfectly known. A skull from Enfield, which I refer 

 to it, comes near Mesopteryx, but has narrower and deeper 

 temporal fossae. The sternum which I refer provisionally to 

 Emeus resembles that of Euryapteryx, but has slight pneu- 

 matic depressions. In fact, Emeus appears to be intermediate 

 between Mesopteryx and Euryapteryx, and further information 

 is necessary before we can say whether it should be joined to 

 either of them. 



It may be thought by some that too many species of moas 

 have already been made ; but with this I cannot agree. The 

 study of individual skeletons has shown me that bones, which 

 I formerly regarded as being merely varieties of one species, 

 belong really to different genera ; and the more I study the moas 

 the more I see the necessity of limiting the amount of varia- 

 tion allowed to each species. An important biological problem, 

 perhaps not found elsewhere, is presented to us in the develop- 

 ment of the moas. This is the variation of an herbivorous 

 race of animals, well supplied with food, and without the check 

 due to the presence of carnivorous mammals preying on them. 

 This problem can only be attacked by studying closely the 

 distribution of the moas both in time and in space ; and to do 

 so it is necessary that the species should be closely defined. 

 Again, the relative ages of our Pliocene and Pleistocene ter- 

 restrial deposits can probably only be ascertained by the help 

 of moa bones, and here, again, unless the different species and 

 varieties are kept separate, we can never obtain the data 

 necessary to settle these questions. 



It may, however, be said, Why give them all names ? Why 

 not consider them as varieties of a few species ? The answer 

 is that there is still plenty of room for varieties within the 

 limits of these species. For example, individuals of Duioruis 

 robustus and D. strcuuus from Enfield are larger than those 

 from Hamilton. The specimens of D. torosus from Enfield 



