DEGENERATIONS, DESMOGNATHUS 237 



On the other hand, there is much that indicates that they are 

 -physiological degenerations. The constancy with which they occur, 

 the definite time of year at which they are most abundant, 

 and especially the location in the testis and the position in the 

 spermatogenetic cycle. This last suggests to us that they bear 

 a relation to the regulation of the spermatogenetic process. Such 

 a regulation appears not to have received much consideration. 

 The investigator's attention is usually so riveted upon the in- 

 tensely interesting intracellular processes involved in the periods 

 of spermatogonial multiplication, synapsis, reduction, etc., that 

 the possibility that these processes may be in some way coordi- 

 nated with the life-habits of the form is generally not discussed. 

 Nevertheless, it will be seen that spermatogenesis is correlated 

 with the mating habits in those forms at least which mate at 

 a definite season. If the multiplication of the spermatogonia and 

 transformation into spermatocytes I is initiated, accelera'ed, 

 retarded or checked at a definite stage, it can mean nothing else 

 than that these processes are regulated growth processes similar 

 to those that lead to the establishment of definite body form. 

 Whether this regulation is intrinsic — within the germ cells them- 

 selves — or extrinsic is a question for the consideration of which 

 there is as yet little basis of fact although analogy would suggest 

 the latter. Possibly the emptying and degeneration of the first 

 maturing lobules and the growth of the interstitial cells accom- 

 panying this may be a factor. Degenerations, therefore, so closely 

 associated with a break in the continuity of the growth process 

 of spermatogenesis seem associated with its regulation, and this 

 view is strengthened by the fact that only the germ cells, not the 

 follicle nuclei, undergo the histolytic change. 



Relation to synizesis. The marked contraction of the nuclear 

 contents into a more or less homogeneous mass which has been 

 described in so many plant and animal forms as occurring at 

 about the beginning of the growth period of the spermatocyte I 

 so closely resembles in its extreme form the rounding off of the 

 nuclei entering on the degeneration changes above described as 

 almost to force a comparison, and one of us (Kingsbury, '02), 

 struck by the strong general resemblance, made a suggestion that 



