TRIPLE MONSTROSITY— CLASSIFICATION 39 



be of this type through inclusion of the smaller acardiac embryo in the body-wall of its more 

 vigorous neighbour. 



B. 1. This is the commonest kind of triple monster in the fish. See cases 2, 4, 5, 6, p. 35. 

 The type usually exhibits bifurcation of one of the branches of an already divided axis, but it seems 

 possible that simultaneous tripartite division may have been present in case 6 of the fish series, and 

 perhaps also in some of the three-headed monsters recorded by older authors, to which reference is 

 made in Taruffi (247 III. 466 d seq.\ Oss. 4, 5, 6, 7, 9, 12, 14). However, very careful dissection 

 will be required before tripartite division is definitely shown to have occurred. In the case of the 

 fish embryo, the examination would need to be done by serial sections. 



The triplicity in the cases just mentioned is anterior, but posterior axial triplicity seems also to 

 occur in mammals (247 III. p. 471 ; Oss. 15, 16, 17). 



B. 2. Specimens 7 and 8 of the fish series belong to this subdivision, which also includes 

 what may be called the classical instance in the human subject, viz. that described by Keina. 1 



B. 3. Examples are recorded by von Froriep 2 in the sheep, and by Fiedler 3 and Bettoli and 

 Fattori 4 in the human subject. 



' Atti dell. Accad. Oioen. 8 p. 203. 'Gurlt'a Lehrbuch der Pathologischen Anatomie, II. p. 201, Berlin 1832. 



'Quoted from 247 III. p. 465. ' Quoted from Bruch, Joiaische Zeilschr. 2?atw. 7 p. 158. 



