MONSTROSITIES. 401 



25. Pygodidymus. — Twins united at the croup ; 1 species : P. averstin 

 (bodies united at the ischia and sometimes at the buttock, and in 

 opposite directions). 



26. CuYi'TODiuYMUs. — Inclusiou of one twin within the other ; 

 2 species: C. abdoininalis (twin included in the abdomen), C. snhcutaiicus 

 (incomplete fix'tus included beneath the skin of the complete one). 



Such is the classification adopted by Gurlt, and it will be seen that 

 it is very complete, while the nomenclature scarcely leaves anything to 

 be desired. Nevertheless, as Saint-IIilaire's classification and nomen- 

 clature are also employed, and are in some respects advantageous to 

 know, we will now allude to them, though not in such detail as we 

 have done those of Gurlt, following the summary given by Zundel. 

 Saint -Hilaire separates monstrosities from vices of conformation, 

 which he distinguishes as Ilcinitcrics, or simple and trifling organic 

 anomalies, and Ilctcrotiuies, or mere changes in the situation of organs, 

 and nearly always without alteration in relative position and connec- 

 tions. For the llcnnapJirodisms — due to the union of the sexes or 

 some of their characters in the same individual — he forms a separate 

 class, which he again divides into two sub-classes, according as there 

 is an absence or excess in the number of parts ; he distinguishes male 

 hermaphrodism, female hcrmaphrodism, and neutral hermaphrodism ; 

 mixed ; complex — masculine or feminine ; and bi-sexual — perfect or 

 imperfect. The monstrosities — properly so called — exhibiting anomalies 

 which are more or less serious, either because of the injurious intiuence 

 they exercise on the functions of the individual, or the vicious con- 

 formation they give rise to — are divided into two classes : Simple 

 Monstrosities and Composite, Double, or Triple Monstrosities. 



The first class comprises three orders: 1. Autositic Monstrosities 

 (avTO'i, self, cr/to5, nourisliment) — whose organs are capable of maintain- 

 ing them for a variable period after birth. Only one or more regions 

 of the body are involved, the majority being little, if at all, ditlerent 

 from the normal standard ; the circulatory apparatus is always more 

 or less complete, particularly the heart ; the lungs, nearly all the 

 digestive viscera, and at least a portion of the head, are present ; and 

 all the anatomical and physiological characters are manifested exter- 

 nally by the general conformation, which, in the greater part of the 

 body, remains symmetrical and almost normal. 2. Omphalositic 

 Monstrosities (d/x<^aAos, u)nhilicus, and ytros-, noiirislnnent) — those whicli 

 live imperfectly, being maintained by the nourishment derived from 

 the mother through the umbilical cord, and dying as soon as the cord 

 is ruptured. These omphalositcs are deficient in a large number of 

 organs, and those which are present are generally very imperfect ; 

 externally all the regions appear to be anomalous, and the symmetry 

 is imperfect, or even effaced. 3. Parasitic Monstrosities — the most im- 

 perfect of all, and generally inert, irregular masses, composed of bones, 

 adipose tissue, etc., destitute of umbilical cord, and attached to the 

 generative apparatus of the mother, at whose expense they maintain 

 an obscure parasitic existence, by means of a vascular pedicle. 



The double monstrosities are divided into autositarian and double 

 parasitic. The first are composed of two individuals more or less 

 intimately united, and somewhat equal in development ; this equality 

 indicating that they both have been equally nourished, and that their 



functions have been alike complete. The second are composed of two 



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