INDEX TO STRUCTURES AND SUBJECTS. 



The italic numbers refer to pages in the text, while the erect Roman and ordinary numerals refer to Plates and Figures. 

 01. I., 01. ii., etc. indicate different Classes of double monstrosity, while a., trans., norm., horiz., etc. are abbreviations 

 respectively for section, transverse, normal, horizontal, etc. 



Absence, 52 (of lateral muscles) : 54 (of notochord) : 55, 61 (of 

 certain fins) : 61 (of eye) : XXVI. 113 (absent notochord). 



Acardiac condition in triple monster, 34, 39. 



Acquired, abnormalities, xi. See also under environment. 



Air-ducts or air-sacs, 13 (normal): 15 (01. I.): IS (01. II.) : 

 XII. 45 (a. horiz. 01. 1.) : XXII. 95, XXIII. 97, 98 (triple 

 monster). 



Albinism, 56. 



Alimentary canal. See under intestinal canal and stomach. 



Alternation of generations, xi, 5. 



Ambicoloration, 56-57. 



Amphibia, 5 (twinning) : 25 (hemididytnus) : 37 (super- 

 numerary parts). 



Anadidymus, 3 (classification): 6-7 (mode of origin, frequency, 

 etc.) : 9-23, 30-33 (structure). 



Anakatadidymus, 3 (classification) : 7 (mode of origin, etc.) : 

 23-24 (structure, etc.). See also 30-32. 



Anal fin. See under ventral edge membrane. 



Aorta (dorsal), 14 (01. i.) : 18 (01. n.) : IV. 18-19, VI. 24-26 

 (s. trans, norm.): VI. 27-29 (s. trans. 01. vi.): VII. 32 

 (triple monster) : IX. 38 (s. trans. 01. i.): XVI. 55 (s. 

 horiz. 01. in.): Ao in XVIII. 67 (01. I.), 68 (01. n.): 

 XXIII. 69 (triple monster) : XXVI. 113 (s. trans, absent 

 notochord). 



Aorta (ventral). See under truncus arteriosus. 



Aortic arch, or root, IS (normal): 14 (01. I.) : 17 (01. n.): 

 IV. 18 (s. trans, norm.): XI. 42 (s. horiz. 01. i.): XIV. 

 51 (s. trans. 01. n.) : XVIII. 67 (01. i.), 68 (01. n.). 



Apical growth, 28. 



Arrest of development. See under defect and parasitism. 



Artery. See under carotid, caudal, choroidal, hyoid, pseudo- 

 branch. 



Artificial breeding of trout, 2 (first account of). 



Ascidia, 48 (hermaphroditism). 



Atavism, 5 (in relation to twinning, etc.): 45, 48 (herma- 

 phroditism) : 50 (pug-head). 



Atrophy. See under defect and parasitism. 



Auditory cartilage. See under labyrinth and periotic. 



Auditory organs, inner, 10 (Moser's specimen) : 17 (01. II.) : 

 26 (hemididymus). See also under otocyst, saccule, 

 semicircular canal, utricle. 



Auricle of heart, 13 (normal): 19 (01. m.): 20 (01. iv.): 

 IV. 18 (s. trans, norm.) : IX. 38 (s. trans. 01. i.) : XVI. 

 54 (s. horiz. 01. HI.): Au in XIX. 73 (normal), 74 

 (01. in.), 75(01. IV.). 



Atitogenetic origin of various abnormalities, xi, 5, 45, 51, 55. 

 Axial organs, 8, 29 (in parallel sets) : 25 (in hemididymus) : 



38 (in triplicity). See also under notochord, spinal cord, 



etc. 



Basihyal (or hypohyal) : 11 (normal): 16 (01. II.): XVI. 



54 (s. horiz. Cl. in.): bh in XVII. 58 (01. I.): Bff in 



XVIII. 64 (01. i.), 65 (01. n.). 

 Barbels, additional, 61. 

 Bile ducts, 19 (01. in.): 20 (01. iv.): XVI. 54 (s. horiz. 



01. HI.) : XXII. 95 (triple monster). 

 Birds, 1, 5, 8, 29, S3, 37 (double or multiple forms) : 38-39 



(triplicity). 



Bladder. See under air and urinary. 

 Blastocyst, 8 (mammalian) : 38 (of sheep) : 38 (of Tatusia). 

 Blastoderm, 6, 37 (extension over yolk) : 6, 8-10, 35-37 (two 



or more embryos on one blastoderm). 

 Body cavity, 24 (anakatadidymus) : 25 (mesodidymus) : 48 



(hermaphroditism): V. 23 (s. horiz. norm.): XII. 46 



(s. horiz. 01. I.). 

 Brain cavity, in parallel union, 29 : diagrams of, XVIII. 69 



(normal), 70 (01. i.), 71 (01. n.), 72 (01. i.): XXI. 90, 



93 (showing planes of sections). 

 Branchial cartilages. See under visceral arch. 

 Bulldog-head, 48 et seq. 



Calcification, premature, of notochord, 53. 



Canal of spinal cord, V. 21 (a. horiz. norm.) : XV. 52 (s. 



horiz. 01. in.): Spc in XVIII. 69-71. See also under 



spinal cord. 

 Cardinal vein, 12 (normal): 19 (01. m.): 20 (01. iv.): IV. 



19-20 (s. trans, norm.): V. 23 (s. horiz. norm.): XVI. 



54 (s. horiz. 01. in.). 



Carotid artery, 13 (normal) : 14 (01. i.) : 17 (01. II.). 

 Carron river, " tailless " trout from, 56. 

 Cartilage. See under basihyal, ceratohyal, copula, glosso- 



hyal, haemal arch, hyoid, hyomaudibular, hypohyal, 



Meckel's, neural arch, olfactory, palato-pterygoid, para- 



chordal, pectoral girdle, periotic, tegminal, trabeculae 



cranii, visceral arch. 

 Caudal artery, 20 (01. v.) : 23 (01. vi.). 

 Caudal fin, 13 (normal): 22 (Cl. vi.): 34 (triple monster): 



53 (hemididymns) : 54-55 (various abnormalities). 

 Caudal vein, 20 (Cl. v.) : 21, 23 (Cl. vi.) : VI. 26 (s. trans. 



norm.) : VII. 31 (s. trans. Cl. VI.), 32 (triple monster). 



