MICHIGAN ACADEMY OF SCIENCE. 15 



count in this species should be made from mature rather than ripe proglot- 

 tids. 



Female organs. The vagina Hes anterior or posterior to the cirrus-pouch 

 but most frequently posterior. Its opening into the common genital atrium 

 is likewise anterior or posterior but never dorsal as in some proteocephaUds. 

 In one proglottid out of forty examined the vagina crossed the cirrus-pouch. 

 In this instance the vagina lay posterior to the cirrus-pouch, then was bent 

 anteriad across the inner end of the pouch and then passed to the mid-field 

 of the proglottid. That portion of the vagina lying in the mid-field of the 

 proglottid is usually thrown into sinuous curves which are more pronounced 

 near the ovarian region. These curves are also more pronounced in strongly 

 contracted than in extended proglottids. A sphincter vaginae is not visible 

 in 'in toto' preparations. Even in transections no definite sphincter vag- 

 inae can be distinguished. There are a few scattering muscle fibers in the 

 region about the initial part of the vagina which perhaps may belong to an 

 inefficient sphincter muscle, but it is by no means certain that these fibers 

 form a part of the musculature of the vaginal wall. A receptaculum seminis 

 of the kind figured for 0. filar oides is found at or posterior to the mid-piece 

 of the ovary. 



The vitellaria are lateral, made up of small acini which are more numerous 

 toward the posterior end of the segment. On the porose side the vitelline 

 field is divided into two areas, the anterior area containing from one to ten 

 follicles. The bilobed ovary (PL 1 figs, 1 and 5) occupies the usual posterior 

 position. The lobes are long, straight and heavy, and are made up of anas- 

 tomosing tubules and many small acini. The organs of the interovarial space are 

 arranged in the manner common to the group. The ducts (oviduct, vagina, 

 and uterine passage) lie in numerous coils. The oocapt is muscular and is 

 surrounded by numerous gland cells. It measures from 0.053 to 0.063 mm. 

 in diameter. The ootype with the so-called shell-gland has a maximum 

 traverse dimension of about 0.10 mm. 



The ripe uterus is made up of a median stem and 15, 18, 19, or 20 long 

 lateral outpocketings on either side. These pouches occupy the larger part 

 of the area between the vitellaria thus covering up the greater number of 

 the testes. Examination of transverse sections of ripe proglottids shows 

 that the uterus with its pouches has replaced almost the entire medullary 

 parenchyma and even the thickness of the cortical parenchyma dorsal and 

 ventral to the uterus is reduced. No uterine pores were observed. 



The development of the lateral uterine pouches agrees with the descrip- 

 tions of their development by Schneider (1904) for Proteocephalus esocis and 

 by La Rue (1910) for 0. filaroides. An early stage in development is shown 

 (PI. 1 fig. 5) which represents a proglottid measuring about 0.9 mm. long 

 by 1.15 mm. broad, and occurring .29 mm. posterior to the head. Here the 

 lateral pouches are made up of strong solid strands of cells. At this stage 

 the testes and ovary though still immature are rapidly approaching maturity. 

 The cirrus-pouch and vagina are slender and immature. The anlage of the 

 uterine pouches can be traced forward to a point 22 mm. from the head 

 where proglottids measure about 0.48 mm. long by 0.9 mm. Inroad. Here 

 the anlage are composed of short slender strands of cells. At this point 

 ovary, testes and vitellaria are evidently far from mature. The cirrus- 

 pouch and vagina are slender. Neither cirrus-pouch, vas deferens, vagina 

 nor median stem of the uterus shows a lumen. 



Eggs. Uterine eggs only were studied. Eggs are spheroidal, surrounded by 

 two membranes which probably represent the two outermost of the three 



