368 Harris Hawthorne W ilder 



notliiug more than a working hypothesis, which may point out the direc- 

 tion in which needed work may be done, and its establishment, modi- 

 fication or refutation are a matter of indifference so long as our knowl- 

 edge of the subject is advanced. Concerning the probability of each 

 of the points suggested the reader must judge after the consideration of 

 the following report, which presents the results of my investigation of 

 the subject. 



As material I have had the opportunity of studying the following 

 monsters ; the numbers given in connection with them being those under 

 which I have filed them in my notes. These will be used for convenient 

 reference throughout the paper. 



I. I'ig embryo; Diprosopus tetrophthalmus. [Lambert.] 

 II. Two-headed snake (Storeria). [Davison.] 

 III. Human Synote (imperfect Janus), advanced fetus. [Bald- 

 win.] 

 lY. Human Thoracopagi, one parasitic ; advanced fetuses. [Wis- 

 tar Inst. Coll. No. 2884.] This specimen is figured by Hirst 

 and Piersol, Part IV, Pis. XXXVIII and XXXIX. ' 

 V. Chick embryo, two bodies, head apparently single, but imper- 

 fectly formed. [Smith College Laboratory, incubated.] 

 VI. Human Cyclops, child at term. [Wistar Inst. Coll. Xo. 

 6956.] 

 VII. Pig Cyclops, large fetus. [Wistar Inst. Coll. Xo. 2913.] 

 VIII. Human Paracephalus. [Wistar Inst. Coll. Xo. 4926.] This 

 specimen is figured by Hirst and Piersol, Part III, PI. XXIA^. 

 IX. Pig embryo, perhaps a Cyclops, but very imperfect. [Lam- 

 bert.] 

 X. Human Omphalopagi, advanced fetuses. [Wistar Inst. Coll. 

 Xo. 4996.] This specimen is figured by Hirst and Piersol, 

 Part IV, PI. XXXV. 



emphasize the position talcen here, that true oosniobia of all sorts, normal, 

 excessive, and defective, are due to a cause existing in the germ, or applied 

 during the very early stages of development, and it is there that our efforts 

 should be directed if we may hope to produce such an organism artificially, 

 a result that we can hardly expect to reach by purely mechanical means. 

 As the tendency to produce duplicate twins and other sorts of abnormal 

 cosmobia seems inherent in certain organisms, and to be transmitted by 

 heredity, it Is quite possible that we may be able to breed certain of the 

 viable forms. In this connection the remarkable experiments of Stockard, 

 which are now being carried on, are of the greatest moment, and will yield 

 important conclusions. 



