244 CALIFORNIA ACADEMY OF SCIENCES. 



The testes in somite x are much more lobed than those 

 in somite xi the latter being entire or heart-shaped while 

 the former are multi-lobed. 



While this appears to be rather constant, I do not 

 think any great specific value should be placed on the 

 shape of the testes, the lobes varjnng in form and num- 

 ber (fig. 3 and 4). 



Sperfn-sacs (fig. i, ssl. and ss.). There are two con- 

 stant and two pairs of variable sperm-sacs. The constant 

 sperm-sacs are found in somites ix and xii; the varia- 

 ble ones in x and xi. These latter sperm-sacs vary 

 much as regards their size. All the sacs are situated 

 principally in the upper part of the body. The sperm- 

 sacs in somites x and xi are connected, but those in ix 

 and xii appear entirely isolated, neither connected with 

 the other sacs or with each other. 



The sperm-sac in somite ix, consists of a heavy globu- 

 lar mass attached to the posterior septum, between somites 

 ix and x above the oesophagus. It is lobed, there being 

 at least four or six large lobes and several smaller ones. It 

 is connected by very narrow tubes following the septum, 

 with the testes in somite x. The sperm-sac in somite 

 xii is of a different and very characteristic shape. It 

 is much lobed and covers the upper and front part of the 

 sacculated intestine in this somite like a well-fitting collar. 

 It is attached to the anterior septum separating somites 

 xi and xii. The lobing of these sperm-sacs is much 

 greater than those in the somite ix. These sperm-sacs 

 are not connected with those in somite x and xi. The 

 latter sperm-sacs are entire, not lobed. They are only, 

 present in very mature worms and are of variable size. 

 When fully developed they fill the larger part of these 

 somites, which are besides crowded by the hearts, testes, 

 ciliated rosettes, etc., found in them. The presence or 



