Arteries in Monsters of the Diceplialus Group 443 



is obviously essential it means the accumulation of a mass of unrelated 

 facts, each fact interesting in itself, but valuable only as it contributes 

 to a fuller understanding of the subject as a whole. 



H. H. Wilder^ has pointed out that a certain class of monsters may 

 pass through a development as natural, orderly, and symmetrical as a 

 normal individual "in accordance with the laws of growth inherent in 

 the organism." He has granted that the monsters in this class are 

 uniisual, "abnormal" in the root meaning of the word, but they are 

 neither deformities nor malformations, and should be carefully distin- 

 guished from deformed or pathological anomalies. This distinction 

 Wilder has made, and he has shown that the class includes "forms with 

 less and those with more than the normal number of parts," and that it 

 suggests an almost complete single series of symmetrical anomalies lying 

 upon either side of and including normal beings. If this be true, it 

 further suggests a progressive relationship between defective and dicepha- 

 lous monsters. 



This separation of unusual from deformed or pathological monsters 

 necessitates a distinct term for the former, one which is broad enough 

 to include also normal beings. Wilder has proposed the name Cosmo- 

 BiON (plural Cosmobia) meaning "an orderly living being," and since 

 he has explained the term in full I shall adopt its use without further 

 consideration. 



The verity of his assumption that there is, "First, a distinction be- 

 tween the symmetrical anomalies on either side of a normal being and 

 the various sorts of deformed and misshapen monsters resulting from 

 abnormal conditions during development, and, second, the possibility 

 of considering in a single series both those forms with less and those 

 with more than the normal number of parts, including also normal 

 beings," can be proved only by the investigation of the structure of 

 all kinds of cosmobia, and by careful comparisons of those that belong 

 in the same series. Hence, what are needed now more than descriptive 

 investigations are comparative investigations of material already at 

 hand. 



This paper is presented, therefore, as the first comparative study of 

 cosmobia with the hope that it may stimulate further research in this 

 field. I shall endeavor to show that the four cases of monsters, studied 

 in the details of their internal anatomy, represent four progressive 

 stages between normal creatures and complete, symmetrical duplicity, 



^Wilder, H. H.. Morphology of Cosmobia, this Journal, 1908, p. 355. 



