On the Oviparous Species of Onychophora

ON THE OVIPAROUS SPECIES OP ONYCHOPHOLU. 363 On the Oviparous Species of Onychophora. By Arthur Dendy, D.Sc, F.L.S., Professor of Biology in the Canterbury College, University of New Zealand. With Plates 19—22. CONTENTS. PAGE 1. INTRODUCTION ....... 363 II. THE GENUS OOPERIPATUS ..... 368 a. Diagnosis ...... 368 b. External Characters ..... 369 c. Internal Anatomy ..... 372 d. Eggs and Development ..... 375 e. Distribution and (Ecology .... 386 / Phylogeny 387 III. DESCRIPTION OF SPECIES AND SYNONYMY . 393 1. Ooperipatus oviparus .... 393 2. Ooperipatus viridimaculatus . 399 3. Ooperipatus insignis .... 403 IV. SUMMARY OP RESULTS ..... 408 V. LIST OF LITERATURE REFERRED TO . 410 VI. DESCRIPTION OF FIGURES ..... 413 I. INTRODUCTION. THE present memoir is an attempt to bring together and extend our information with regard to a very remarkable group of Onychophora, the species of which are characterised by their egg-laying habit and by a corresponding change in 364 ARTHUR DENDY. the structure of the female organs. The subject is one upon which I have been engaged at intervals for more than twelve years, and our knowledge of which for various reasons has progressed very slowly. Owing in part, at any rate, to an unfortunate confusion in nomenclature, for which I can scarcely hold myself entirely responsible, my earlier observations were at first met with scepticism1 and hostile criticism, (Fletcher, 6) and the scarcity of material and difficult nature of the investigation were equally discouraging. The recent discovery of a new egg-laying species in New Zealand has, however, stimulated further inquiry, and though I cannot even now make the work anything like complete, I think the time has come when a general account of the subject with the necessary illustrations may be found useful. As previous observations on these species have been published in scattered periodicals, I prefix to this memoir a short historical notice. In December, 1888,1 found two specimens of Peripatus in a fern-tree gully at Warburton, on the Upper Yarra, Victoria. These specimens I described in a letter to 'Nature' (1), published on February 14th, 1889.2 Peripatus had previously been known from Victoria only by a single specimen discovered at Warragul by Mr. R. T. Baker, and exhibited by Mr. J. J. Fletcher at a meeting of the Linnasan Society of New South Wales on July 27th, 1887. Mr. Fletcher (1) considered the specimen to be "in all probability an example of P. Leuckartii, Sanger." Owing, however, to the peculiar colour-markings of the Warburton specimens, I came to the conclusion that these belonged to a new species, which I, however, refrained from naming. In reply to my letter to f Nature ' Mr. Sedgwick (3) wrote to the same journal (February 28th, 1889), and expressed a doubt as to the distinctness of the Victorian species. The examination of additional specimens unfortunately 1 Compare Sedgwick (4, p. 10). " All species are viviparous. It lias lately been stated that one of the Australian species is normally oviparous, but this has not been proved." 2 Also in 'The Victorian Naturalist,' January, 18 9 ON THE OVIPAROtJS SPHCIES OF ONYCBOPHOllA. 365 convinced me that Messrs. Fletcher and Sedgwick's sugges- tions as to the specific identity of the Victorian species with P. Leuckartii were correct, and on several subsequent occa- sions (2, 3, 4, 5, 6, 7, 8, 9) I referred to the Victorian species under that name. In 1891 I made the somewhat surprising discovery that the Victorian Peripatus, unlike all other known species, lays eggs, and I therefore announced that P. Leuckartii was oviparous (6, 7, 8, 9). For making this statement I was very severely criticised by Mr. J. J. Fletcher (6), who certainly showed conclusively that the common New South Wales Peripatus is viviparous, like the great majority of species, a fact which, through the kindness of my friend Mr. T. Steel, I was subsequently enabled to verify for myself. The unfortunate controversy on this subject, which has probably done much towards preventing zoologists from appreciating the true facts of the case, was really due to the confusion between two species (the nomenclature of one of which is not yet by any means definitely settled), so that perhaps it was hardly worth while to say so much about it. As, however, I replied fully (11) to Mr. Fletcher's criticisms at the time, I need say no more about them in this place. Meanwhile, in 1890, I had described (5), under the name Peripatus insignis, a second Victorian species, dis- tinguished by the presence of only fourteen pairs of walking legs, and this species was afterwards found by Professor Baldwin Spencer (2) in Tasmania, which would appear to be its headquarters. In my Presidential Address to the Biological Section of the Australasian Association for the Advancement of Science, at Brisbane in January, 1895,1 pointed out a further element of doubt which enters into the nomenclature of the Australian species of Peripatus. Professor Baldwin Spencer had obtained in London a translation of Sanger's original diagnosis of Peripatus Leuckartii, of which he had kindly given me a copy. Concerning this I made the following remarks in my address : 366 ARTHUR DENDT. "The diagnosis commences: fFound in New Holland, north-west from Sydney. Fifteen pairs of legs—one pair without claws, fourteen with.' If this be correct, then the common Australian species usually accepted as P. Leuckartii is certainly not the species described by Sanger under that name, for I can certify that it has fifteen pairs of legs, all of which bear claws. There appear to me to be two possibilities in the case: (1) Sanger has failed to observe the claws on one of the pairs of legs, or (2) there were really only fourteen pairs of claw-bearing legs in his specimen, and he counted the oral papillae as a pair without claws. It is difficult to say which of these alternatives is more likely to be correct, but it seems just possible that my P. insignis may be the real Leuckartii, with only fourteen pairs of claw-bearing legs. The only way to settle the question definitely would be by an appeal to Sanger's original specimen, which is stated to have been in the possession of Professor Leuckart." Up to the present time no such appeal to Sanger's original specimen has, so far as I am aware, been made. After my address was written, when passing through Sydney I called upon Mr. Fletcher and discussed the question of nomenclature with him, and found that he had independently arrived at conclusions similar to those contained in my manuscript. It was then arranged that we should each contribute a paper on the subject at the next meeting of the Linnean Society of New South Wales, and that in my contribution I should confine myself to the egg-laying species of Victoria, which we agreed should receive a name. My description of: P. oviparus (16) was published in accordance with the above arrangement. Before finishing his paper on the subject (7), however, Mr. Fletcher received specimens from Western Australia which caused him to modify his views; and,after a lengthy discussion, he comes to the conclusion that the most satisfactory arrangement would be to consider all known Australian specimens of Peripatus as referable to one comprehensive species with four varieties, viz.: ON THE OVIPAROUS SPECIES OF ONYCHOPHORA. 367 1. P. Leuckartii, var. typica = P. insignis, Dendy. 2. P. Leuckartii, var. occidentalis, var. nov. (for the West Australian specimens). 3. P. Leuckartii, var. orientalis, for the New South Wales and presumably the Queensland specimens (the P. Leuckartii, auctorum). 4. "The Victorian Peripatus to be dealt with by Dr. Dendy," referring to Peripatus oviparus, my description of which is placed after Mr. Fletcher's paper. Although I myself pointed out that P. in signis might be identical with P. Leuckartii, the latter possibly having only fourteen pairs of claw-bearing legs, instead of fifteen, as usually believed, yet I do not by any means consider that the evidence is sufficient to justify the rearrangement proposed by Mr. Fletcher. Indeed, it seems to me very improbable that Sauger should ever have had Peripatus in signis in his possession. In any case the original accounts by Leuckart and Siinger are so inadequate and apparently contradictory that the species (without re-examination of the type) cannot be certainly identified, and therefore we are fully justified in following the usual custom, and applying the specific name Leuckartii to the common New South Wales species, while retaining the name insignis for the very different southern species with fourteen pairs of legs. This question will be more fully discussed later on. So far, however, from agreeing with Mr. Fletcher that all the Australian forms are varieties of the same species, I maintain that there are in Australia two genera of Onychophora each with at least two species. I consider, in fact, that P. oviparus may be regarded as the type of a new genus, for which I have (19) proposed the name Ooperipatus, and in which I also include P. insignis and the species from New Zealand lately (17) described by me under the name P. viridimaculatus. All these three species differ from the common Australian Peripatus (P. Leuckartii, auctorum) in the possession by the female of a prominent 308 ARTHUR DBNDT. ovipositor.1 P. oviparus and viridiraaculatus certainly lay eggs with thick sculptured shells. In P. insignis the same habit may be inferred from the presence of the ovipositor. It is this extremely interesting group of egg-laying species which forms the subject of the present memoir.

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