Citege ef. Cornell Aniversity Library BOUGHT WITH THE INCOME FROM THE SAGE ENDOWMENT FUND THE GIFT OF Henry W. Sage PQCER AA ie AIR rec rats tela nena BELT. 3513-1 i 2 464 ain DATE DUE GAYLORD Cornell University The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu81924024535464 THE CAMBRIDGE NATURAL HISTORY EDITED BY S. F. HARMER, Sc.D., F.R.S., Fellow of King’s College, Cambridge ; Keeper of the Department of Zoology in the British Museum (Natural History) AND A. E. SHIPLEY, M.A., Fellow and Tutor of Christ’s College, Cambridge ; Reader in Zoology in the University VOLUME IV 9. MACMILLAN AND CO., LIMITED LONDON + BOMBAY + CALCUTTA MELBOURNE THE MACMILLAN COMPANY NEW YORK + BOSTON + CHICAGO ATLANTA + SAN FRANCISCO THE MACMILLAN CO. OF CANADA, LTD. TORONTO CRUSTACEA By Grorrrey SmiTH, M.A. (Oxon.), Fellow of New College, Oxford ; and the late W. F. R. Wetpon, M.A. (D.Sc.,Oxon.), formerly Fellow of St. John’s College, Cambridge, and Linacre Professor of Human and Comparative Anatomy, Oxford TRILOBITES By Henry Woops, M.A., St. John’s College, Cambridge ; University Lecturer in Palaeozoology INTRODUCTION TO ARACHNIDA, AND KING-CRABS By A. E. Surprey, M.A., F.R.S., Fellow and Tutor of Christ’s College, Cambridge ; Reader in Zoology EURYPTERIDA By Henry Woops, M.A., St. John’s College, Cambridge ; University Lecturer in Palaeozoology SCORPIONS, SPIDERS, MITES, TICKS, Etc. By Cecrt Wargurton, M.A., Christ’s College, Cambridge ; Zoologist to the Royal Agricultural Society TARDIGRADA (WATER-BEARS) By A. E. Surptey, M.A., F.R.S., Fellow and Tutor of Christ’s College, Cambridge ; Reader in Zoology PENTASTOMIDA By A. E. Suipiey, M.A., F.R.S., Fellow and Tutor of Christ’s College, Cambridge ; Reader in Zoology PYCNOGONIDA By D’Arcy W. Tuompson, C.B., M.A., Trinity College, Cambridge ; Professor of Natural History in University College, Dundee MACMILLAN AND CO, LIMITED ST MARTIN'S STREET, LONDON T909 All the ingenious men, and all the scientific men, and all the fanciful men, in the world, with all the old German bogy- painters into the bargain, could never invent anything so curious, and so ridiculous, as a lobster. CuHar.es Kincs.ey, The Water-Babies. For, Spider, thou art like the poet poor, Whom thou hast help’d in song. Both busily, our needful food to win, We work, as Nature taught, with ceaseless pains, Thy bowels thou dost spin, I spin my brains, Soutnry, To a Spider. Last o’er the field the Mite enormous swims, Swells his red heart, and writhes his giant limbs. Erasmus Darwin, The Temple of Nature. PREFACE Tue Editors feel that they owe an apology and some explanation to the readers of Vhe Cambridge Natural History for the delay which has occurred in the issue of this, the fourth in proper order, but the last to appear of the ten volumes which compose the work. The delay has been due principally to the untimely death of Professor W. F. R. Weldon, who had undertaken to , write the Section on the Crustacea. The Chapter on the Branchiopoda is all he actually left ready for publication, but it gives an indication of the thorough way in which he had intended to treat his subject. He had, however, superintended the preparation of a number of beautiful illustrations, which show that he had determined to use, in the main, first-hand knowledge. Many of these figures have been incorporated in the article by My. Geoffrey Smith, to whom the Editors wish to express their thanks for taking up, almost at a moment’s notice, the task which had dropped from his teacher’s hand. A further apology is due to the other contributors to this volume. Their contributions have been in type for many years, and owing to the inevitable delays indicated above they have been called upon to make old articles new, ever an ungrateful labour. The appearance of this volume completes the work the Editors embarked on some sixteen years ago. It coincides with the cessation of an almost daily intercourse since the time when they “came up” to Cambridge as freshmen in 1880. S. F. Harmer. A. HE. SHIPLEY. March 1909. CONTENTS PAGE SCHEME OF THE CLASSIFICATION ADOPTED IN THIS VOLUME : ‘ i xi CRUSTACEA CHAPTER I CRUSTACEA GENERAL ORGANISATION 3 ‘ 3 CHAPTER II CRUSTACEA (continued) Entomostraca —- BRANCHTIOPoDA — PHYLLorvopA — CLADOCERA — WATER- FLEAS ‘ ' 18 CHAPTER III CRUSTACEA ENTOMOSTRACA (continued) CopEPODA . : F : , . 55 CHAPTER IV CRUSTACEA ENTOMOSTRACA (continued) CiRRIPEDIA—PHENOMENA OF GROWTH AND SEX—OsTRACODA . 79 vil Vill CONTENTS CHAPTER V CRUSTACEA (continued) . PAGE Maxacosrraca: LEprosrRaca—-PHYLLOCARIDA: EUMALACOSTRACA. SYN- CARIDA — ANASPIDACEA: PERACARIDA — Mysipacra — CUMACEA — IsoPODA—AMPHIPODA : HopLocARIDA—STOMATOPODA 110 CHAPTER VI CRUSTACEA MALACOSTRACA (continued) EUMALACOSTRACA (CONTINUED): EvcARIDA — EUPHAUSIACEA — COMPOUND Eyres—DeEcapoba . 144 CHAPTER VII CRUSTACEA (continued) REMARKS ON THE DISTRIBUTION OF MARINE AND FRESH-WATER CRUSTACEA. 197 CHAPTER VIII CRUSTACEA (continwed) TRILOBITA : ; ‘i 221 ARACHNIDA CHAPTER IX ARACHNIDA—INTRODUCTION . 255 CHAPTER X ARACHNIDA (continued) DELOBRANCHIATA = MEROSTOMATA— XIPHOSURA 259 CHAPTER XI ARACHNIDA DELOBRANCHIATA (continued) EURYPTERIDA=GIGANTOSTRACA . . , . 283 CONTENTS ix CHAPTER XII ARACHNIDA (continued) PAGE EMBOLOBRANCHIATA—SCORPIONIDEA—PEDIPALPI . ‘ » 297 CHAPTER NIII ARACHNIDA EMBOLOBRANCHIATA (continued) ARANEAE—EXTERNAL STRUCTURE—INTERNAL STRUCTURE . 4 . 314 CHAPTER XIV ARACHNIDA EMBOLOBRANCHIATA (continued) ARANEAE (CONTINUED) — Hapirs —Ecpysis— TREATMENT OF YouNG— MIGRATION — Wets — Nests — Eaa-cocoons — Porson — FErriniry — ENEMIES—PROTECTIVE CoLORATION—MIMICRY—SENSES—INTELLIGENCE —Marine Hapirs—FosstL SPIDERS . 838 CHAPTER XV ARACHNIDA EMBOLOBRANCHIATA (continued) ARANEAE (CONTINUED)—CLASSIFICATION ‘ . 3884 CHAPTER XVI ARACHNIDA EMBOLOBRANCHIATA (continwed) PALPIGRADI—SOLIFUGAE = SOLPUGAE—CHERNETIDEA = PSEUDOSCORPIONES . 422 CHAPTER XVII ARACHNIDA EMBOLOBRANCHIATA (continued) Popocona = RIcInuLEI— PHALANGIDEA = OPILIONES— HaBITS—STRUCTURE— CLASSIFICATION ‘ , 439 CHAPTER XVIII ARACHNIDA EMBOLOBRANCHIATA (continued) Acarina—Harvest-pucs— Parasitic Mires—Ticks—Spinnincg MiTEs— STRucTURE—M ETAMORPHOSIS—CLASSIFICATION i 454 x CONTENTS CHAPTER XIX ARACHNIDA (APPENDIX I) PAGE TARDIGRADA — OccURRENCE — Ecpysis — SrrucruRE — DEVELOPMENT — AFFINITIES—BIO0LOGY—DESICCATION—PARASITES—SYSTEMATIC . . 477 CHAPTER XX ARACHNIDA (APPENDIX II) PENTASTOMIDA — OccuRRENCE — Economic ImporTANCE — STRUCTURE — DEVELOPMENT AND Lirs-Histrory—SysrEMATIC 4 4 488 PYCNOGONIDA CHAPTER XXI PYCNOGONIDA ‘ ‘ x ‘ 7 501 INDEX 4 : 543 SCHEME OF THE CLASSIFICATION ADOPTED IN THIS VOLUME The names of extinct groups are printed in italics. Divisions. Orders. r Branchio- poda (p. 18) CRUSTACEA (p. 3). ENTOMOSTRACA (p. 18). Sub-Orders. Tribes. Phyllopoda (pp. 19, 35) Ctenopoda { (p. 51) Calyptomera (pp. 38, 51) | Anomo- Cladocera poda (p. 87) (p. 51) Gymnomera | (pp. 38, 54) 7 \ [cee (p. 57) Gymnoplea | | (p. 57) lauds (p. 58) | Podoplea (p. 61) Ampharthrandria (p. 61) \ (Continued on the next page. ) xi Families. Branchipodidae (pp. 19, 35). Apodidae (pp. 19, 36). Limnadiidae (pp. 20, 36). Sididae (p. 51). Holopediidae (p. 51). Daphniidae (p. 51). Bosminidae (p. 53). Lyncodaphniidae (p. 53). Lynceidae = Chydoridae (p. 53). Polyphemidae (p. 54). Leptodoridae (p. 54). Calanidae (p. 57). Centropagidae (p. 58). Candacidae (p. 60). Pontellidae (p. 60). Cyclopidae (pp. 61, 62). Harpacticidae (pp. 61, 62). Peltiidae (p. 63). Monstrillidae (p. 63). Ascidicolidae (p. 66). Asterocheridae (p. 67). Dichelestiidae (p. 68). xii SCHEME OF CLASSIFICATION Divisions, Orders. Sub-Orders. Tribes. Families. ( i ( ( Oncaeidae (p. 69). Corycaeidae (p. 69). Lichomolgidae (p. 70). Ergasilidae (p. 71). Bomolochidae (p. 71). Chondracanthidae (p. 72). Eucopepoda ; Podoplea ; Isokerandria Philichthyidae Copepoda | (contd.) (contd.) 1 (p. 69) \ (p. 78). (contd. ) Nereicolidae (p. 73). Hersiliidae (p. 73). Caligidae (p. 73). Lernaeidae (p. 74). Lernaeopodidae (p. 75). Choniostomatidae a ae l (p. 76). “p. 76) } Argulidae (p. 76). Polyaspidae (p. 84). 3 Pentaspidae (p.87). PORRNe Miata Spe) Tetraspidae io 88). Anaspidae (p. 89). ( Verrucidae (p. 91). Octomeridae (p. 91). Operculata (p. 89) + Hexameridae Cirripedia . : (p. 91). (p. 79) Tetrameridae (p. 92). Acrothoracica (p. 92). Ascothoracica (p. 93). Apoda (p. 94). Rhizocephala (p. 95). Cypridae (p. 107). Cytheridae (p. 107). Halocy pridae (p. 108). Ostracoda Cypridinidae (p. 107) (p. 108). Polycopidae (p. 109). Cytherellidae (p. 109). 3 MALACOSTRACA (p. 110). Canu, Trav. Inst. Zool. Litte. vi., 1892. III PODOPLEA—AMPHARTHRANDRIA 67 Ascidiella scabra at Concarneau), in which the female has lost its segmentation, the mouth-parts and thoracic legs being purely prehensile, and various species of LHnterocola, parasitic in the stomach of Compound Ascidians, in which the female is a mere sac incapable of free motion, while the male preserves its swim- ming powers and a general Cyclops-form (Fig. 34). We Fig. 34.—Hutervcola fulgens. A, Ventral view of 2, x 85; B, side view of 8, x 106. . Abd.1, 1st abdominal segment; Ant.1, Ant.2, Fic. 35.—Asterocheres Daglacene, &, Ist and 2nd antennae; cm, gland-cells; 1, with egg-sacs, x 57, (After ventral nerve-cord ; og, oviducal gland ; ov, ovary ; Giesbrecht.) po, vagina; Th.1, 1st thoracic appendage ; Th. 4, Th.d, 4th and 5th thoracic segments. (After Canu.) have here the first instance of the remarkable parallelism between the degree of parasitism and the degree of sexual dimorphism, a parallelism which holds with great regularity among the Cope- poda, and can be also extended to other classes of parasitic animals. Fam. 6. Asterocheridae.'—These forms retain the power of swimming actively, and are very little modified in outward appearance by their parasitic mode of life (Fig. 35), though they 1 Giesbrecht, Fawna and Flora G. v. Neapel, Monogr. 25, 1899. 68 CRUSTACEA——COPEPODA CHAP. possess a true siphon in which the styliform mandibles work. The siphon is formed by the upper and lower lips, which are produced into a tube with three longitudinal ridges; in the outer grooves are the mandibles, while the inner groove forms the sucking siphon (see transverse section, Fig. 36). In Ratania, however, there is no siphon. The first antennae possess a great number of joints, and may be geniculated in the male (Cancerilla). The members ; of this family live as ectoparasites on various species of Echinoderms, Sponges, and As- cidians, but they frequently change their hosts, and it appears that one and the same species may indifferently suck the juices of ie Be 36. — Diagrammatic very various animals, and even of Algae. ransverse section through the distal part Cancerilla tubulata, however, appears to live i bere aicetire Oe only on the Brittle Starfish, Amphiura tum (Asterocheridae). squamata. ge co Fam. 7. Dichelestiidae.—The males and females are similarly parasitic, and the body in both is highly deformed, the segmentation being suppressed and the thoracic limbs being produced into formless fleshy lobes ; they are placed among the Ampharthrandria owing to sexual differences in the form of the first antennae. There is a well- developed siphon in which the mandibular stylets work, except in Lamproglena, parasitic on the gills of Cyprinoid fishes; the succeeding mouth-parts are prehensile. The majority of the species are parasitic on the gills of various fish (Dichelestium on the Sturgeon, Lernanthropus’ on Labraa lupus, Serranus scriba, etc.), but Steuer ® has recently described a Dichelestiid (Mytilicola) from the gut of Mytilus galloprovincialis off Trieste. This animal and Lernanthropus are unique among Crustacea through the possession of a completely closed blood- vascular system -which contains a red fluid; the older observers believed this fluid to contain haemoglobin, but Steuer, as the result of careful analysis, denies this. The parasite on the gills of the Lobster, Nicothoe astact, possibly belongs here. The inclusion of Micothoe and the Dichelestiidae among the Ampharthrandria rests on a somewhat slender basis; this basis is afforded by the fact that none of the parasitic Isokerandria have more than seven joints in the first antennae, whereas 1 Arb. Zool. Inst. Wien, ii. 1879, p. 268. * Ibid. xv., 1905, p. 1. se PODOPLEA—ISOKERANDRIA 69 Nicothoe and some of the Dichelestiidae! have more numerous joints. In most of the Dichelestiidae, however, the number of joints is less than seven and practically equal in the two sexes. TRIBE Il. ISOKERANDRIA. The first antennae are short, similar in the two sexes, and are never used by the male as clasping organs. This function may be subserved by the second maxillae. FamMs. ONCAEIDAE, CORYCAEIDAE, LICHOMOLGIDAR, ErGa- SILIDAE, BOMOLOCHIDAE, CHONDRACANTHIDAE, PHILICHTHYIDAE, NEREICOLIDAE, HERSILIIDAE, CALIGIDAE, LERNAEIDAE, LERNAE- OPODIDAE, CHONIOSTOMATIDAE. The families Oncaeidae and Corycaeidae contain pelagic forms of flattened shape and great swimming powers, but the structure of the mouth-parts in the Corycaeidae points to a semi-parasitic habit. Fam. 1. Oncaeidae.—This family, including the genera Oncaea, Pachysoma, ete., does not possess the elaborate eyes of the next family, nor is the sexual dimorphism so marked. Fam. 2. Corycaeidae.—These are distinguished from the Oncaeidae, not only by their greater beauty, but also by the possession of very elaborate eyes, which are furnished with two lenses, one at each end of a fairly long tube. The females of Sapphirina are occasionally found in the branchial cavity of Salps, and their alimentary canal never contains solid particles, but is filled with a fluid substance perhaps derived by suction from their prey. S. opalina may occur in large shoals, when the wonderful iridescent blue colour of the males makes the water sparkle as it were with a sort of diurnal phosphorescence. The animal, however, despite the opinion of the older observers, is not truly phosphorescent. It may be that the ornamental nature of some of the males is correlated with the presence of the curious visual organs, which are on the whole better de- veloped in the females than in the males. As in so many pelagic Copepods, the body and limbs may bear plumed setae of great elaboration and beautiful colour, eg. Copilia vitrea (Fig. 37). We now pass on to the rest of the parasitic Copepods,’ which 1 Heller, Reise der Novara, vol. iii., 1868. 2 For fish-parasites in British waters consult Scott, Fishery Board for Scotland, Scientific Investigations, xix., 1900 et seq. 7O CRUSTACEA—COPEPODA CHAP. probably belong to the tribe Isokerandria, and we meet with the same variety of degrees of parasitism as in the Ampharthrandria, often leading to very similar results. In the first seven families mentioned below there is no Se he SSAZ Ulli nee 7) : ail SS Sa Fia. 37.—Copilia vitrea (Corycaeidae), 9, x 20. (After Giesbrecht. ) siphon. The Lichomolgidae and Ergasilidae have not much departed from the free-living forms just considered, retaining their segmentation, though in the Ergasilidae the body may be somewhat distorted (Fig. 39). In both families the thoracic swimming feet are of normal constitution. Fam. 3. Lichomolgidae.'—These are semi-parasitic in a number of animals living on the sea-bottom, such as Actinians, ? Cann, Joe. cit. p. 66. I PODOPLEA—ISOKERANDRIA 71 Echinoderms, Annelids, Molluscs, and Tunicates, Lichomolgus agilis (Fig. 38) occurs in the North Sea, Atlantic, and Mediter- ranean, on the gills of large species of the Nudibranch, Doris, while Z. albeus is found in the peribranchial cavity and cloaca of various Ascidians. Sabel- liphilus may infect the gills of Annelids such as Sabella, and is common at Liverpool. Fam. 4. Ergasilidae. — hersites (Fig. 39) is parasitic on the gills of various fishes, eg. 7. gasterostei, which is common on Gasterosteus aculeatus on the French and North Sea coasts, and may even be found on specimens of the fish that have run up the River Forth into fresh water. The animal Fic. 38. — Lichomolgus agilis, 3 x10. Abd.1, 1st abdominal possesses claw-like second antennae by segment ; cpth, cephalothorax ; which it clings to its host. Th.1, 1st thoracic segment ; oe 2 . Th.5, 5th thoracic appendage. Similarly characterised by the (After Canu.) Fia. 39.—Thersites gasterostet. A, eg, x 10; B, dg, x 20. Abd. 1 & 2, Fused 1st and 2nd ab- dominal segments; Ant. 1, Ant.2, 1st and 2nd antennae ; ¢.s, egg- sac; Zh, thoracic appendages. (After Gerstaecker. ) absence of a siphon are three other families of fish-parasites, the Bomolochidae, Chondracanthidae, and Philichthyidae. Fam. 5. Bomolochidae.—Pomolochus (Fig. 40), parasitic on the skin of the Sole (Solea) and in the nostrils of Cod (Gadus), is held to be related to the Ergasilidae. The first thoracic limb is remarkably modified. Were it not for the absence of a siphon, it would be hard to separate this family from the Caligidae. 72 RUSTACEA—COPEPODA CHAP. Fam. 6. Chondracanthidae.— These Copepods infest the gills Fira. 40,—Bomolochus, sp. (Bomo- lochidae), x 8. Abd. 1, 1st abdo- minal segment; 1 Claus, Untersuchungen zur Erforschung des Crustaceensystems, Wien, 1876. Brady and Norman, ‘Monograph of the Marine and Fresh-Water Ostracoda of the N. Atlantic,” Zrans. R. Dublin Sov. (2) iv., 1889, p. 63. Miiller, Fauna und Florw G. von Neapel, Monogr. xxi., 1894; “ Deutschlands Siisswasser-Ostracoden,” Chun’s Zoologica, xii., 1900. 108 CRUSTACEA—OSTRACODA CHAP. being pediform and used in walking. The telson in the Cytheridae is rudimentary, but is well developed in the Cypridae. The heart is altogether absent. In many of the fresh-water forms, eg. common species of Candona and Cypris, males are never found, and parthenogenetic reproduction by the females appears to proceed uninterruptedly. Weismann? kept females of Cypris reptans breeding partheno- genetically for eight years. He also remarks on the fact that these, and indeed all parthenogenetic female Ostracoda, retain the receptaculum seiminis, used normally for storing the spermatozoa derived from the male, unimpaired. Some of the Cytheridae occur in deep water. Thus Cythere dictyon was frequently taken by the Challenger in depths of over 1000 fathoms, but the majority prefer shallow water. The Halocypridae and Cypridinidae comprise marine genera Fie, 75,—Asterope oblonga, @, removed from its carapace, x 25. A, Alimentary canal; Aj, 45, Ist and 2nd antennae; FH, eye ; (, gills ; GLO, generative opening ; H, heart; M, mandible; 7, 6th appendage ; 7’, last appendage (cleaning foot). (After Claus. ) of a pelagic habit. The first antennae are chiefly sensory, but the second antennae are biramous, and they do not merely move up and down, as in the preceding families, but sideways like * «