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II. the Subterranean Crustacea of New Zealand

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II. the Subterranean Crustacea of New Zealand 11. 17he Xubterranean Crustacea of New Zealand: with some general Remarks on the ;Fauna of Caves alzd Wells. By CHARLESCHILTON, M.A., D.Sc., F.X.X., Rector, District High School, Port Chalmers, New Zealand. Read 20th April, 1893. (Plates XV1.-XXIII.) CONTENTS. Page I. Introduotion ................................................................ 163 11. Historical Sketch . , . , . ,. .. 165 111. History, Distribution, and Occurrence of the New Zealand Subterranean Crustacea . 180 IV. Detailed Descriptions of the New Zealand Subterranean Crustacea . 185 Isopoda. The Genus Phreatoicus : P. ccssimilis, sp. nov. ; P. typicus, Chilton ; Comparison of the three known species of Phreutoiczcs ; Special points in the structure of Phreatoicus ; Affinities of Phrecctoicus . 185 The Genus Cruregens: C. fontanus, Chilton . 209 Amphipoda. The Genus Crungonyx : C. compactus, Chilton . 218 The Genus Gcimmams : G. fragilis, Chilton . .. 226 The Genus Cnlliopius : C. subtermneus, Chilton . , . , . , . .. 233 Summary of the more important points in Part IV. , . , . 244 V. The General Fauna of the Subterranean Waters of Canterbury . , . ,. , . 246 VI. The Canterbury Plains and their Underground Waters . :. 248 VII. Origin of the Subterranean Crustacea . 253 VIII. The Special Characteristics of the Subterranean Fauna : Colour ; Loss of Eyes ; Compensation for Loss of Eyesight ; Food ; Arrested Development ; Habits ................................................................ 259 IX. Bearings of the Phenomena of Subterranean Life on the Theory of Descent . 266 X. Conclusion .................................................................. 272 XI. Bibliography . .. 273 XII. Explanation of the Plates . .. .. .. .. 281 I. INTRODUCTION. INthe following paper an attempt is made to give a fuller account than has yet been published of the Blind Crustacea found in the underground waters of the Canterbury Plains in the South Island of New Zealand. The existence of similar Crustacea in the caves and wells and in the deep waters of lakes in Europe and North America has long been known, and has attracted much attention, both because of the inherent interest of the subject, and because of the bearing that the facts have on some general questions of Biology connected with the Theory of Descent, particularly on the effects of yse and disuse, and on the influence of the environment on the animals. SECOND SERIES.-ZOOLOGY, VOL. VI. 22 164 DR. C. CHILTON ON THE SUBTERRANEAN 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 Wrzeiniowski’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, helonging to five different 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, Cammarus, is more or less allied to the blind Niphargzcs of Europe, the species of which were indeed originally assigned to Gammarus, and are still so assigned by some writers. Two genera are new : one, Crzcregem, belongs to a family, the Bnthzcridz, no members of which were prmiously known to inhabit underground waters, and the other, Phreatoiczcs, 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 remarkable 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 their occurrence and distribution, of their habits, and of the peculiarities 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 geueral questions of Biology. For 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 Ashburton, 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. Nr. Smith, of Ashburton, has been particularly zealous and CRUSTACEA OF NEW ZEALAPU-D. 165 unwearying in his efforts to obtain specimens for me, and I am much indebted to him for additional knowledge on their distribution and on the general question of the underground waters of the plains. My friend and fellow-worker, Mr. G. M. Thomson, Science Master of the Dunedin High Schools, has assisted me in many wags by his advice and criticism, and by his kindness in supplying me with works from his library that I could not otherwise have obtained. To many writers I am indebted for copies of their various papers, particularly to Professor A. S. Packard and to Dr. R. Moniez, who have sent me copies of important works by them on the subterranean fauna of their respective countries ; while, in common with all other workers on the Amphipoda, I am greatly indebted to the Rev. T. R. R. Stebbing for the very full and valuable Bibliographical Introduction to his Report on the Challenger ’ Amphipoda. Situated as I am at the Antipodes, far from the chief biological libraries of Europe and America, to which one would have liked to have recourse, I can perhaps appreciate the full value of this introduction better than those who are more favourably circumstanced in this respect. 11. HISTORICALSKETCH. The following historical sketch of the growth of our knowledge of the Sessile-eyed Crustacea inhabiting caves and wells is in many respects very imperfect, for I am unable to consult many of the original papers and works quoted ; it contains, however, I trust, references to most of the more important works on the subject. In its compilation I have derived much assistance from Alois Humbert’s paper on Niphargw putea$iw, var. Forelii [62], Professor Packard’s paper on the (‘Cave Fauna of North America ” [83], from Wrzebiowski’s work on “ Three Subterranean Amphipoda ’) [12$], and from the bibliographical introduction Lo Stebbing’s “ Report on the Challenger ’ Amphipoda ” [108]. I have endeavoured to include the Subterranean Isopoda as well as the Amphipoda, but the part’s bearing on them are, I fear, much more incomplete than those on the Amphipoda, as there is no general bibliography on the Isopoda at all comparable to that which Stebbing has compiled with so much care and labour for the Amphipoda. F~NZYON PAULA SCHRANK, in his account of Gammarus pulex [98, p. 5351 says, ((Habitatin aquis, Tivis, fontibus ; albiesimus dum natat.” From the words ‘(in fontibus ; albissirnus durn natat ” Stebbing po8, p. 31) thinks it is fair to infer that Schrank had seen one of the well-shrimps. If this be SO it would appear that we have in this work of Scbrank (1781) the first mention of Subterranean Crustacea. W. E. LEACH[72]. The first undoubted reference to “well-shrimps” appears to have been made by Leach. In the article “ Crustaceology ” in the ‘ Edinburgh hncyclopaedia,’ published probably in 1813-1814, after Gammarus pukx a species is mentioned [72, p. 4031 which is not numbered but <( which Mr. Leach considers to be different from pulex.” It came from a well in London. (( It differs principally from Gammarus pulex in having the upper process of the tail much longer. The co1our, when alive, was cinereous, but so translucent that the eyes could not be distinguished. It stands in Mr. Leach’s cabinet under the specific name subterraneus.” It is evident from this brief description that the animal in question is not a true Gammarus, but is a subterranean species, probably a Niphargus. Stebbing j108, p. 841 thinks it is probably identical with Niphargus aquilex, Schiodte, 0 22” 166 DR. C. CHILTON ON THE SUBTERRANEAN and it is assigned to this species also by Spence Bate and Westwood [4, p. 3161. Wrzehiowski [124, p. 6021 thinks that the description given is scarcely sufficient to enable us to decide whether the animal belongs to Niphargus aquilex, Schiiidte, or Crangonyx compactus, Spence Bate ; but in the latter species the terminal uropoda are not very long, and, as Leach specially mentions that they are long in his specimen, it appears more likely that it is a Niphargus.
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