38 BOTANICAL GAZETTE [jantjary 



development of the extremity 



in the form 



uncommon 



pigment 



the tubercles proper to the upper side. 



An interesting case in animals, which has lately come to my 



notice, is furnished by a crab, the claw being modified as shown in 



fig. 6. The superfluous claw, developed 

 upon the normal dactyl, repeats in detail 

 the style of the larger claw, as regards 

 the general form and even the teeth. 10 



Fig. 6. — Crab claw, showing . . 



homoeosis. moulting. 



The formation is believed not to be 

 congenital, but to result from a wound 

 to the normal claw near the time of 



The presence of the principle in 

 animal development greatly enhances the interest which the botanical 

 student of morphogenesis must entertain with respect to homoeosis. 



In plants the transposition of organs has frequently been described 



m\ — _ 



in teratolog 



enomena 



confused with those of a different nature, and the larger relations of 

 homoeotic formations have not been recognized by teratologists. 

 Masters devotes a short chapter to the subject, under the caption 

 heterotaxy 11 — an expression which, as used by him, seems only in 

 part to cover the ideas I am here endeavoring to formulate. Mas- 

 ters' chapter is a miscellany of teratological facts which will not go 



compendium. His 



metamorphy 12 is too general for the present ^ 



10 Photograph in St. Nicholas Magazine 25:177. 1907. The specimen is in my 

 possession. A number of similar anomalies have been described by W. Faxon, Bull. 

 Mus. Comp. Z06I. Harv. Coll. 8:257. 1881; by F. H. Herrick in "The American 



11 i 4 1 TV It mm j~ Mi m M 



writers 



work a summmary appears in Bateson's Materials. These authors do not specifically 

 recognize the homoeotic nature of the anomaly. 

 "Vegetable teratology 156. 1869. 



"It will be remembered that Goethe employed the word metamorphosis in a 

 different sense. Sachs, again, has a definition: "Metamorphosis is the varied develop- 

 ment of members of the same morphological significance resulting from their adapta- 

 tion to definite functions."— Sachs, Text-book of botany, tr. by Bennett & Dye* 



(1875). tax. 



