48 ILLINOIS BIOLOGICAL MONOGRAPHS [398 



glottid. In the specimen at hand, however, they extend across the field 

 continuously in a manner identical with the description by Hall for 

 C. mosaica. There is of course no reason to doubt the correctness of 

 Stiles ' observation ; but it seems evident that the condition he described 

 is not diagnostic. As mentioned, I have found the testes in C. pectinata 

 almost separated in two fields. 



Hall recognizes in his specimens some differences from Stiles' ac- 

 count as to the time of first appearance of genital organs. He acknowl- 

 edges that such differences may be due to differences in technique and 

 mentions that Stiles' account was based upon unsectioned material. 

 I have not attempted to section the anterior end of the specimen at 

 hand since it is not in condition for close study. However there is no 

 valid reason for considering the specimens different on this point. The 

 mosaic markings mentioned by Hall can hardly be considered of im- 

 portance; anyway, they are shown to a slight extent by the specimen 

 at hand. 



There are no other points of difference between the two accounts. 

 I have compared Stiles' cotype in nearly every particular with Hall's 

 account and find only two points of difference : ( 1 ) eggs appear first 

 in the uterus in the 94th proglottid; and (2) the ovary is 850^ across, 

 and of somewhat different appearance from the condition Hall de- 

 scribes. These points of difference are taken up in the paragraph after 

 the next. 



Specimens of this form from cottontails (Sylvilagus floridanus) 

 at Blair, Oklahoma, show the ovary exactly as described by Hall and 

 of the same dimensions, that is, about 600/x across. The cirrus pouch 

 is somewhat smaller, and old pouches, when gorged with sperm, shorten 

 up and become pearshaped. In two specimens sexual maturity is 

 reached in the 90th proglottid. In other points they do not differ from 

 Hall's description. Figures 46 to 49 are from this material. These 

 Oklahoma specimens, it will be seen, resemble the Maryland specimen 

 in that maturity is reached about the 90th proglottid. The gorging and 

 shortening up of the cirrus pouch suggests an explanation of the basis 

 of Stiles' measurements. The general appearance of the worms is 

 identical with both the Maryland and the Colorado forms, and the 

 form of the ovary is identical with that of those from Colorado. It 

 seems very probable that the appearance of the ovary presented by the 

 Maryland specimen is due to the flattening process to which it was 

 subjected preparatory to mounting in toto. The lobes stretching out 

 laterally at full length are in just the position they would assume with 

 such treatment. As to the difference in the stage at which maturity is 

 reached, the same explanation would apply here as for Anoplocephala 



