106 VETERINARY PATHOLOGY. 



the male in conformation. There was quite a well marked 

 vulva and the much elongated clitoris projected about four 

 inches postero-inferiorly and closely resembled a penis. The 

 uterus was quite rudimentary and the reproductive glands were 

 located near the normal location of the internal inguinal ring 

 and had very little resemblance to either testicle or ovary. 

 Microscopic examination did not solve the difficulty for the 

 glands were a conglomerate of small cysts. The mammary 

 gland was fairly well de\-eloped. 



Double or Multiple Malformations. — Under this caption 

 those malformations will be considered that in\olve two or more 

 individuals developing simultaneously. Marchand's classifica- 

 tion of duplicate monsters is adhered to in the following discus- 

 sion. The entire subject of duplicate monsters may be subdi- 

 vided into 1st, svmmetrical duplicity, 2nd, asymmetrical dupli- 

 city, and 3rd, multiplicity. 



SYMMETRICAL DUPLICITY'. — The individuals, in symmetrical 

 duplicity are, in the beginning, similar and symmetrical. Each 

 of the symmetrical duplicates is deri\ed from separate, similar, 

 equal anlagen of a single fertilized ovum or bisection of a single 

 anlagen. This class of malformations majr be divided into two 

 groups: — viz., complete and incomplete duplicities. 



Complete DitpUeity. — Complete duplicates are in the begin- 

 ning alike and complete and the individuals may remain sep- 

 arate thus forming twins, (free duplicities,) or they ma)? be 

 united, thus forming double monsters. 



Twins, (free duplicates), develop in a single chorion though 

 each individual usuall)? has a separate amnion and allantois. 

 Monochorionic duplicates may develop equally or unequally, 

 depending upon the division of nourishment. The above dis- 

 cussion primarily applies to uniparous animals. However, by 

 varying the number it is equally ajiplicable to multipares. 

 Twins also result from simultaneous fertilization of two ova. 



Double monsters are mono-chorionic duplicities in which the 

 bodies are united. The two bodies may be equal or unequal in 

 size, depending upon the distribution of nourishment. Double 

 monsters are the result of partial fission of a fertilized ovum, 

 partial fusion of two separate anlagen of a single ovum, or par- 

 tial fusion of two fertilized ova. The attachment of the two 

 bodies of the dr)uble monsters may be posterior, middle or anter- 

 ior. 



P(isterior union may be dorsal or ventral. In the former the 

 union occurs at the pelvis, and the dorsal surfaces of the bodies 

 are usually in apposition, such a monster is called a pvgopagus. 



