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Nachdruck verboten. 



The female urogenital Organs of the limbless Lizard Anniella. 



By W. R. CoE and B. W. Kunkel, 

 Sheffield Biological Laboratory, Yale University, New Haven, Conn. 



With 2 Figures. 



The limbless lizard, Anniella pulchra, which inhabits the barren 

 sand plains of central and southern California and other portions 

 of the southwestern United States, presents a number of anatomical 

 peculiarities that have not been described for any other type of lizard. 

 The most striking of these relates to the urogenital organs of the female. 



This degenerate lizard is a member of the Amphisbaenidae, 

 apparently presenting closer affinities with the European limbless 

 lizard Anguis, than with any other form. 



As is the case in Anguis, Anniella is ovo - viviparous , the 

 adult female giving birth to two living young about the month of 

 September. Both of these embryos develop in the right oviduct, the 

 left oviduct being represented by a small, glandular tubule only. 



In all of about 20 females examined both ovaries are functional, 

 and both are about equal in size. The right, howewer, is situated a 

 little more anteriorly than the left as is the case in many other 

 reptiles (Figs. 1, 2). A single ovum in each ovary is usually distinctly 

 larger than any of the others, so that evidently a single egg is dis- 

 charged from each genital gland at each breeding season. 



Both of the eggs, however, pass into the right oviduct through 

 its large anterior ostium and take up positions in its middle, or 

 uterine, portion (Fig. 2). They are then elongated oval in shape, a 

 broad constriction being formed in the middle portion at the time of 

 the development of the embryo. The egg becomes firmly imbedded in 

 the walls of the uterus, although the nourishment for the embryo is 

 probably derived wholly from the yolk. When nearly mature the 

 embryo lies coiled or folded lengthwise in the long axis of the egg. 

 The young lizard measures from 70 to 80 mm in length at the time 

 of birth. 



It is the aborted left oviduct, however, to which special attention 

 is to be directed. This organ has degenerated to such an extent that 

 it is quite incapable of performing its normal function, and exists merely 



