1871.] 409 [Wilder. 



involved. One word as to the historical sketch; I can hardly hope 

 to have done justice to all; especially to those whose works have not 

 been directly accessible; but while the diagrammatic arrangement of 

 the authors will make my errors more apparent, it will also enable 

 every one to find or alter his own proper place, or that of another 

 upon the scheme. 



Finally I beg that the whole paper may be viewed as a " topog- 

 raphy of our ignorance," and as an effort to map out our future 

 work, rather than as an ad captandum attempt to decide the great 

 questions herein presented. 



ADDENDA. 



Page 161. It is worth noting that the great work of Bourgery and Jacob 

 contains the following suggestion to a symmetrical comparison of the membra, 

 which, however, like many another, fell still-born ; "En resume, l'epaule n'est 

 autre chose que le bassin renverse." Anat. de l'homme, torn i, p. 107. 



Page 169. I trust that the new technical terms here proposed will not be 

 included by the Rev. J. G. Wood in his reference to the " Cacophonic combina- 

 tions of syllables" (111. Nat. Hist, of Birds, p. 173). Yet his general criticism 

 upon scientific nomenclature is w r ell merited; and would only perhaps be more 

 useful if coming from one whose style was less diffuse than that of the above- 

 mentioned popular writer. 



Page 173. Synonyms of Annularis; from Huxley, 78; Ulnar finger, p. 266, 

 Ulnar digit, p. 270; Fourth digit, p. 269. 



Page 311. As to the morphical value of numerical composition Mivart says, 

 " I think the degree of segmentation of such structures (ribs) of very little 

 consequence morphologically." Vertebrate skeleton, p. 374. 



Page 326. The phrase " morphological value " occurs in Wy man's paper on 

 the Development of Raia batis, 337, 35. 



Page 328. As to establishing different kinds of groups upon certain organs, 

 Agassiz says, " No system can be true to Nature which is based upon the con- 

 sideration of a single part, or a single organ" ; 201, 289. And Alfred Newton, in 

 reviewing Huxley's new classification of Aves, speaks as follows: "It does 

 seem a question very much deserving of attention, how far any approach to a 

 natural system can be based upon the modifications of one part of an animal's 

 structure, without any reference whatever to other portions of it." Zoolog. 

 Record, 1867, p. 48. 



Page 330. Agassiz intimates that orders are based upon internal structure, 

 in contradistinction to form upon which families are founded ; 201, 213. 



Page 332. I greatly regret that Kowalewsky's researches upon the develop- 

 ment of Amphioxus were not accessible to me when this paper was written: 

 the little creature is a good illustration of the contrast between teleological 



