357] AX0PL0CEPHAL1DM—D0UTHITT 7 



lateral tips extend a little farther distad than the median portion and 

 cross the excretory ducts ventrally on either side. The anterior and 

 lateral margins together form a semicircle, so that at this stage the 

 uterus as a whole is somewhat semilunar in outline. The early develop- 

 ment of the uterus will be taken up later (page 51). Development 

 from the stage just described is first by enlargement and coalescence of 

 tubes, forming a saccular structure ; then by regular outpocketing, ante- 

 riorly, distally, and laterally. The anterior and lateral pockets together 

 number about 22; the distal, 15. Since neither specimen possessed 

 completely ripe proglottids, a study of the embryo was unfortunately 

 not possible. 



The dorsal excretory duct lies laterad of the ventral and usually 

 somewhat more dorsal. The diameter of the ventral is 30/* and that of 

 the dorsal 7/*. The transverse commissure is of very small diameter 

 and is not visible at all in sections at hand except in proglottids past 

 sexual maturity. 



The presence of the prostate gland and the reticulate uterus show 

 at once that this species is allied to the genus Andrya. It disagrees 

 however with the accepted diagnosis in that (1) the pores are strictly 

 dextral, (2) the ovary is not nearer the pore side than the opposite side, 

 (3) the testes extend laterad across the ventral excretory duct on the 

 aporose side; and (4) the later development of the uterus is by regular 

 anterior and posterior outpocketing. 



The first point of disagreement is not an important one since 

 unilaterality is approached in all of the species of the genus. The sec- 

 ond point, while significant in other aspects cannot be regarded as of 

 generic import since the other female glands are displaced in the regular 

 manner. The third point will be shown to be true also of known and 

 new species of Andrya, Anoplocephala, and Bertiella; so that the 

 descriptions of these genera are in error, and this character, supposed 

 to be confined to the genus Aporina, is found in all the single-pored 

 genera of the subfamily except Schizotaenia. As to the fourth, the 

 discrepancy seems to be due to errors in the descriptions of the species 

 already known; for while Stiles (1896), describing the uterus of Andrya 

 rhopalocephala says it is in its final stages a simple sac or with ' ' at most 

 extremely fragmentary and rudimentary divisions", his figures of 

 gravid uteri of this species and A. cuniculi (see his Plate VIII, fig. 1 

 and Plate IX, fig. 1) show for both species what is apparently regular 

 outpocketing, correctly drawn tho misinterpreted. 



This cestode shows several characters which mark it as the most 

 primitive species known in the genus ; and if the contention later made 



