52 KANSAS UNIVERSITY QUARTERLY. 



form condition and if No. 35 had reached this stage, the beginning of 

 this period varies with different individuals. 



Thus, in the two cases mentioned above, it would seem that we 

 have exceptions to the general rule of alternation of forms ; having 

 in one case a large second-form individual retaining the second-form 

 condition after exuviation, and in the other an animal which was 

 probably in the first-form condition remaining first-form after exuvia- 

 tion. It seems to me not at all imjarobable that No. 11 also represents 

 one of these "abnormal" changes, being large enough to be in first- 

 form condition, and yet again assuming the second-form just at the 

 time when all others are first-form. 



As to the microscojjic condition of the testes, these specimens are 

 not very dissimilar to others collected the same spring (Nos. 21 to 37). 

 Of No. 34, all the lobes and the vas deferens were sectioned. The 

 lobe is made up proximally of emptied follicles. Upon this follows 

 an extensive zone of spermatocytes, many of them in active mitosis. 

 The distal end of the lobe is occupied by the spermatogonial zone, 

 which is composed of only a few follicles in one of the lobes. The 

 vas deferens is filled with spermatozoa. Of No. 35, two lobes and the 

 vas deferens were sectioned. In this specimen the posterior lobe is 

 very much larger than either of the anterior lobes, but, so far as our 

 present consideration is concerned, this seems to me to be of no great 

 significance. The condition of the elements is very similar to that of 

 No. 34. The vas deferens is well filled with spermatozoa. In both of 

 these specimens we notice a predominance of spermatocytes. The 

 relative extent of the spermatocytes as compared with the other zones 

 is, with the exception of the one lobe of No. 34 mentioned above, not 

 so great as in the one lobe of No. 37 which was examined. With the 

 exception of the proportionately greater extent of the spermatocyte 

 zone, No. 37 is very similar to Nos. 34 and 35. 



Faxon, in his paper on "Dimorphism," says: "I will add that the 

 males of extraordinary size which I have seen are all of the 'first-form.' 

 Do these very old individuals cease to molt ? Do they become per- 

 manently capable of reproduction ?" My observations, so far as they 

 extend, confirm those of Doctor Faxon. Having seen some very large 

 second-form males of both 6'. vir'ilis and 6'. immunis, I must add, 

 however, that this observation is true of only the extraordinarily large 

 individuals. While such a hypothesis seems not at all unreasonable, 

 I should like to examine a much larger series of material than I have 

 yet had the opportunity of doing before I say that the males reach a 

 permanently first-form condition. It seems to me improbable that 

 the old individuals should cease to molt, but not at all improbable 

 that they should continue in the same form after molting. 



