224 R. R. HUMPHREY 



Spengel (76) describes the testis as consisting of ^capsules'* 

 opening by means of collecting tubules to a large collecting duct. 

 The lobules vary in their relations to the main collecting duct, 

 and on the basis of this variation, Spengel recognized three struc- 

 tural types. The testis of his first type has a longitudinal col- 

 lecting duct central in position, around which the lobules occupy 

 a radial position; this type is seen in Batrachoseps, Gyrinophilus, 

 Plethodon, and Spelerpes. In this type the lobules are of a 

 fairly uniform conical or pyramidal shape, each with its base 

 extending to the periphery of the organ and its apex lying ad- 

 jacent to the central collecting duct, to which it opens directly 

 by a single short unbranched tubule. The testis of this type, 

 as might be expected, is cylindrical, though varying in diameter 

 in different portions at different seasons, for reasons which will 

 become apparent later in this discussion. In the second type of 

 organ the longitudinal canal is superficial, and, when seen in a 

 transection of the testis as in figure 3, the lobules appear arranged 

 in the fashion of an open fan, as in Necturus and Crj^ptobranchus. 

 As in testes of the first type, each lobule extends from the pe- 

 riphery to the vicinity of the longitudinal collecting duct; the 

 latter is located in the connective tissue at the hilus, which runs 

 the full length of the testis. In Necturus this longitudinal duct 

 has more the nature of a series of enlarged irregular chambers, 

 connected, however, by narrower passages into a continuous 

 chain, from which smaller tubules are given off; each smaller 

 tubule branches irregularly, the terminal branches finally con- 

 necting with the apices of the elongated, conical lobules. In 

 Spengel's third type the lobules are described as being more 

 spherical and terminating the numerous divisions of a much- 

 branched collecting duct; here, as may be seen in figure 7, not 

 all the lobules extend from main duct to periphery, but many 

 are entirely peripheral in position, being supplied by long 

 branches running out to them, between the more centrally placed 



5 1 shall use in this discussion the preferable term 'lobules' introduced by 

 Kingsbury ('02). He considered them as being, probably and essentially, homol- 

 ogous with the lobules of the mammalian testis, though not differentiated into 

 tubuli contorti in the urodele as in the mammal. 



