x 5 6 



THE QUARTERLY REVIEW OF BIOLOGY 



testis of the Top Minnow (Gambusia 

 affinis) may be eightfold (i 8) . The period 

 of maximum size is from November to 

 February. No spermatogenesis occurs 

 during cold weather. Again no mention 

 is made regarding interstitial cells. This 

 should not be construed as indicating that 

 they do not exist. The data offered by 

 these two investigators show the relation 

 between testicular size and spermatogei 

 sis. This is in turn directly related to s 

 activity. 



Courrier (ix and 13) reported that 

 the Stickleback (Gasterosteas aculeatus) sp- 

 matogenesis occurs during March. It 

 progresses rapidly, so that by the end of 

 the month it is completed and most of the 

 lobules contain spermatozoa. 



During spermatogenesis the seminal 

 elements distend the cysts so that they 

 press tightly against each other. Only a 

 thin layer of connective tissue in addition 

 to the blood vessels and nerves then 

 separates the lobules. Courrier records 

 that early in April after the end of sperma- 

 togenesis the interlobular spaces begin to 

 change and that in May and June the cells 

 in these spaces are filled with many mito- 

 chondria and secretion granules. He 

 refers to these cells as forming an intersti- 

 tial gland and suggests that they have 

 increased because there exists a need for 

 a product they secrete. According to 

 Courrier, the purpose of these "glandular" 

 cells is to secrete a testicular hormone 

 which produces the bright, nuptial colora- 

 tion and sex activity. He further states 

 that in May and June fish that do not 

 have the nuptial appearance have no trace 

 of interstitial cells though they have 

 spermatocytes and spermatogonia. These 

 are probably males that mated early and 

 have lost their mating apparel. 



Champy (10) found many Sticklebacks 

 with nuptial apparel in the winter but 

 with interstitial cells poorly developed or 



absent. They are rare or absent at the 

 time that spermatozoa ripen, which is at 

 the opening of the mating season. He 

 studied development in many other species 

 of fish and could find no correlation be- 

 tween presence of interstitial cells and 

 development of secondary sex characters 

 or modifications of appearance that are 

 found during the mating season. In 

 ! 



stitial cells at any period of th 

 pedes de 

 g 

 that these anatomic changes appeared to 

 be correlated with the maturity of 

 spermatozoa. 



Van Oordt (37 and 38) also made obser- j 

 vations upon Gasperosteui 

 found tbs ■:.. — • 



ei, time of which he fails to designate, 

 coi ins no spci es but that 



then filled with spermatozoa. Large: 

 grou A itiai ceils are then found i 



at the r.crs of two or three canals. In 

 August, when secondary sex characters 1 

 are largely gone and the tubules contain 

 early stages of spermatogenesis, the inter- 

 tubular spaces are quite wide and contain 

 groups of interstitial cells. In October 

 spermatogenesis has continued, distending 

 the lobules, and only a few interstitial 

 cells are then present (38). In winter, 

 when secondary sex characters are not 

 developed, he found some testes in which 

 there existed a broad interstitium with 

 many interstitial cells. In spring he found 

 that secondary sex characters appear as 

 spermatogenesis advances. He concludes 

 from cytological findings that the inter- 

 stitial cells increase when sper 

 is suspended becai 10 " 

 with nouri 

 is late 



epithelium durinj the & ceil 



prolifen 



