B. F. Kingsbury 103 



foimd to be quite full of spermatozoa. This, of course, affords no due 

 to the time of mating or ovulation. Examination of the testis shows 

 that the mass of spermatozoa leave it in the early fall, so that it con- 

 tains but few ripe spermatozoa. But the ducts are well filled and in 

 the spring the cloaca as well contains a mass of spermatozoa upon a 

 jelly-like base, presumably a spermatophore. This suggests a spring 

 mating with quite probably a fall one also. 



Nomenclature and Spermatogenetic Cycle. 



It is perhaps hardly necessary to define the meaning of the terms 

 that will be used in this paper as applied to the generations of cells in 

 spermatogenesis, so universally have La Valette St. George's, 76, names 

 of (a) spermatogonia, (b) spermatocytes of the first order, (c) sperma- 

 tocytes of the second order, (d) spermatids and (e) spermatozoa, been 

 used in all recent work; and so well recognized are the corresponding 

 periods which they characterize— (a) a 'period of multiplication, (b) a 

 period of growth or maturation, (c) a reduction period, sometimes spoken 

 of as the maturation period, and (d) the period of transformation, some- 

 times also called the maturation period. Meves has further divided the 

 spermatogonia into large and small spermatogonia, a division which, 

 as a matter of convenience, seems to be helpful, though McGregor's 

 terms of primary and secondary spermatogonia are preferred by the 

 writer. 



In Salamandra, as Flemming early pointed out, the spermatogenesis 

 forms an annual cycle in which in adaptation to the breeding habits of 

 the animal, the stages succeed each other in chronological order and 

 characterize certain periods of the year. After mating in the spring a 

 multiplication of the residual spermatogonia takes place which continues 

 during the months of April, May and June. During late spring and 

 early summer occurs the period of growth and maturation of the sperma- 

 togonia to form the spermatocytes; during June, July, and also into 

 August, the reducing divisions are taking place, followed by the trans- 

 formation of the spermatids into spermatozoa in August and September. 

 The testis in the winter is filled with ripe spermatozoa, which are emitted 

 in the following spring, when another yearly cycle begins. 



In Desmognathus the cycle is shifted but slightly, so that the char- 

 acteristic periods occur at nearly the same times as in Salamandra. 

 The testis of animals killed in the autumn (October, November) contain 

 none or but few ripe spermatozoa; the spermatogonia are, however, 

 dividing and the secondary spermatogonia have entered upon their 



