98 F. M. BALFOUR AXD W. N. PARKER. 



with the nriniferous tubuli. The semen is thus transported 

 through the kidney into the kidney-duct (segmental dact), 

 and so to the exterior. No trace of a duct homologous with 

 the oviduct of the female was found in the male. 



With reference to the development of the excretory system^ 

 the authors have established the following points : 



(1.) That the segmental (archinephric) duct is developed 

 as in Teleostei. 



(2.) That a pronephros^ resembling in the main that of 

 Teleostei, is developed from the anterior end of the segmental 

 duct. But they find that the pronephric chambers^ each 

 containing a glomerulus, into which the coiled pronephric 

 tubes open, are not, as in Teleostei, completely shut off from 

 the body cavity, but remain in communication with it by 

 two richly ciliated canals, one on each side of the body. 



(3.) The pronephros eventually undergoes atrophy. 



(4.) Some of the mesonephric tubes have peritoneal 

 funnels in the larva. 



(5.) The ovarian sac continuous with the oviduct is estab- 

 lished by a fold of the peritoneal membrane, near the attach- 

 ment of the mesovarium, uniting with the free edge of the 

 ovarian ridge to form a canal, the inner wall of which is 

 constituted by the ovarian ridge itself. 



(6.) The posterior part of the oviduct is not formed until 

 the ovarian sac has become developed, and had not been 

 developed in the oldest larva (11 centims.) the authors have 

 succeeded in obtaining. 



The Alimentary Canal and its Appendages. — In this section 

 the authors give a detailed account of the topographical 

 anatomy of the alimentary tract in the adult. They have 

 detected a small pancreas close to the bile-duct, and call 

 special attention to a ventral mesentery passing from the 

 posterior straight section of the intestine to the ventral wall 

 . of the body. 



In the embryological part of the section a detailed account 

 is given of the development (1) of the pancreas, which is 

 described as arising as a dorsal diverticulum of the duodenum 

 on a level with the opening of the bile-duct; (2) of the yolk 

 sac and vitelline duct; (3) of the spiral valve, which first 

 appears as a hollow fold in the wall of the intestine, taking 

 a slightly spiral course, and eventually becoming converted 

 into a simple spiral ridge. 



The so-called hyoid gill, which the authors expected to 

 find well developed in the larva, is shown not to be found 

 even in the oldest larva the head of which was examined (26 

 mm.). 



