INDEX OF SUBJECTS. 



Acanthoderes nigricans, double (?) leg, 



548 

 Acanthodrilus, double tail, 565 

 Acanthothyris, double monster, 566 

 Accessory hoofs of Ox, connected with 



supernumerary digits, 285 

 Acherontia atrojjos, colours of larvae, 304, 



305 

 Acinojms lepelletieri, extra legs, 498 

 Actinometra, variation in number of 



radial joints, 421; 4-rayed specimen, 



437 ; 6-rayed, 437 

 Adaptation, Study of, as a method of 



solving problems of species, 10 ; 



logical objection to the method, 12 ; 



speculations as to, avoided, 79; of 



species, approximate only, 11 

 Adimonia tanaceti, double (?) antenna, 



550 

 Agabus uliginosus, double (?) leg, 548 

 Agestrata dehaanii, extra legs, 491 

 Agonum sexpunctatum, double (?) leg, 



547; viduum, double (?) antenna, 550 

 Agra catenulata, extra legs, 512 

 Akis punctata, double (?) antenna, 551 

 Alaua sordidus, extra legs, 508 

 Aleochara masta, extra legs, 488 

 Allantus, extra appendage, 544 

 Allolobophora, generative organs of, 160, 



162, 165 ; duplicity of head and tail, 



565; lissaensis, sperinatheca?, 165 

 Allurus, generative organs of, 164, 165 ; 



putris, 165 ; hercynius, tetraedrus, 164 

 Alytcs, vertebrae, 127; axial duplicity, 



561 

 Ainblypneustes, 4-rayed, 443; 6-rayed, 



446 ; partial reduction of a ray, 443 ; 



partial duplicity of a ray, 446 

 Ammocvctes, alleged case of eight pairs 



of gill-openings, 174 

 A»i})edus ephippium, double (?) antenna, 



551 

 Amphicyclus (Holothurian), tentacles 



not in multiples of five, 435 

 Amphimallus solstitialis, extra antennae, 



515 

 Amphioxus, number of gill-slits, 174 

 Anagallis arvensis, colour-variation, 44 

 Anas querquedula, division of digits, 392 

 Anchomenus sexpunctatus, extra antenna?, 



523; double (?) antenna, albipes, an- 



gusticollis, 550 

 Angora breeds, 55 

 Anisoplia Jloricola division of epistome, 



454 

 Annelids, segmentation compared with 



that of Chordata, 86; imperfect seg- 

 mentation, 156; spiral segmentation, 



157 ; variation in generative organs, 

 159 ; axial duplicity, 563 

 Anomala junii, extra antenna?, 515 

 Anser, spinal nerves, 130, 133 

 Antcdon, variation in number of radial 

 joints, 421; 4-rayed specimen, 436: 

 6-rayed specimen, 437; abnormal 

 branching, 438 

 Antenna developed as foot, 146, 147 

 Antenna?, variation in number of joints, 

 Prionida?, 411; Polyarthron, 

 412; Lysiphlebus, 412; 

 Donacia, 413; Forjicula, 

 413 

 extra, in Secondary Symmetry, 

 513-522 ; symmetry un- 

 known, 522; arising from 

 head, 551 . 

 supposed double, 548 

 Anthia, extra legs, 502 

 Anthocharis cardamincs, colour-varia- 

 tion, 45 

 euphcno, 45 ; ione, 72 

 Anthropoid Apes, Variation in Verte- 

 bra?, 116; teeth, 199; digits, 349 

 Aphodius, extra legs, 494 

 Apis mellifica, union of compound eyes, 



461 

 Appendages, joints of, 410 



supernumerary, arrange- 

 ment of evidence, 474 

 in Secondary Symmetry, 

 475 ; mechanical model 

 illustrating relations, 

 480; duplicity of, 406, 539 

 Apteryx, brachial plexus, 130 

 Apus, extra flabellum, 536 

 Aquila chrysaetos, extra digits, 393 

 Arcliibuteo lagopus, extra digit, 392 

 Arctia, colour-variation, 46 

 Arctocephalus australis molars, 243 

 Argepherusa, eye-spots, 295 

 Arion, sinistral, 54 



Aromia moschata, extra legs, 485, 503, 

 512 ; double (?) antenna, 3 cases, 551 

 Artemia, salina and milhausenii, 96; 

 gracilis, 100; relation to Branchipus, 

 96 ; segmentation of abdomen, 100 

 Arteries, renal, 277; in a case of double- 

 hand, 333 

 Arthronomalus, number of segments, 94 

 Arthropoda, variation in number of 

 segments, 87; Homceosis in append- 

 ages, 146; axial duplicity, 565 

 Articular processes, change from dorsal 

 to lumbar type, 109; variations in 

 position of change, 110, 112, 114, 117, 

 122 



