164 DE. C. CHILTON ON THE SUBTEREANEAN 



The existence of these animals in New Zealand was first recorded by me [22] about 



eleven years ago, but the original descriptions, though fairly accurate so far as they go, 



were very short and meagre, and the figures were rough and crude, and many points 



were left on which fuller and more complete information was much to be desired. 



Moreover, during the time that has elapsed since they were first discovered, much 



additional information has been gathered as to their occurrence and distribution, and 



no connected account of these has as yet been published. During the same time, too, 



some important works on the Blind Subterranean Crustacea of other parts of the world 



have appeared, particularly Packard's work on the Cave Fauna of North America [83], 



and Wrzesniowski's very important memoir on "Three Subterranean Amphipoda" [124]. 



If we consider the peculiarities of the New-Zealand fauna and flora, and remember 



that New Zealand forms by itself a distinct zoological province, which has long been 



more or less perfectly isolated from other provinces, we should naturally expect that 



the Subterranean Crustacea of New Zealand would present us with some new interesting 



facts, and that they would differ largely from the similar Crustacea found elsewhere. 



This proves to be the case. The Subterranean Crustacean fauna is peculiarly rich, and 



much more varied than that of either Europe or North America ; so far as at present 



known, it consists of six distinct species, three Amphipods and three Isopods, l)clouging 



to five difi"erent genera. Of these genera Crangonyx is already known from the 



subterranean waters of Europe and North America, but none of the others have been 



recorded from underground habitats elsewhere, though one, Gammarm, is more or less 



allied to the blind Niphargm of Europe, the species of which were indeed originally 



assigned to Gammariis, and are still so assigned by some writers. Two genera are 



new : one, Cruregens, belongs to a family, the AnthuridcB, no members of which were 



previously known to inhabit underground waters, and the other, Phreatoicus, which 



now contains three species (two from the subterranean waters of New Zealand, and 



one freshwater one from the top of the Mt. Kosciusko plateau in Australia), is so peculiar 



that it forms the type of a new and very remai-kable family of the Isopoda. 



In the following pages I give a full detailed description of the external anatomy of 

 each of these six species, in addition to the brief specific diagnoses and, usually, a 

 discussion on the characters of the genus. I have given what is known of theu* occurrence 

 and distribution, of their habits, and of the paculiarities which they present in common 

 with or in addition to other Subterranean Crustacea ; their probable origin is discussed 

 at some length. I have given also a short historical introduction showing the growth 

 of our knowledge on the subject of Cave and Well Sessile-eyed Crustacea; and have 

 concluded with some remarks on the bearing of the facts presented by them on the 

 general questions of Biology. 



Eor their kindness in providing me with material, I have to record my best thanks 

 to Mr. R. M. Laing, of the Christchurch Boys' High School, Mr. E. Wilkinson, of the 

 School of Agriculture, Lincoln, Messrs. J. B. Mayne and W. W. Smith of Asliburton, 

 Mr. D. L. Inwood and Miss Young of Winchester. Mr. W. P. Hay of Irvington, 

 Indiana, U.S.A., has kindly supplied me with specimens of some North-American 

 Subterranean Crustacea. Mr. Smith, of Ashburtou, has been particularly zealous and 



