xm 



PHYLUM CHORDATA 



233 



B 



ccelome. An ovary of this kind reminds us of the state of things 

 in Arthropods, in which also the ovary is a hollow organ dis- 

 charging its products into its internal cavity, whence they pass 

 directly into the continuous oviduct. It was pointed out that the 

 lumen of the ovary in this case was to be looked upon as a shut-off 

 portion of the coelome : this is certainly the case in Lepidosteus 

 and the Teleostei. In 

 the embryo a longi- 

 tudinal fold grows 

 from the ventral edge 

 of the then solid ovary, 

 and turns upwards 

 along the lateral face 

 of the organ : it is met 

 by a descending fold 

 of peritoneum from 

 the dorsal wall of the 

 abdomen, and by the 

 union of the two folds 

 a cavity is enclosed, 

 which is the lumen of 

 the ovary. The ovi- 

 duct is developed as a 

 backward continuation 

 of these folds of peri- 

 toneum, and appears 

 to be quite uncon- 

 nected with the em- 

 bryonic renal system, 

 and therefore not to 

 be homologous with 

 the oviducts of Elas- 

 mobranchs and Holo- 

 cephali, which, as we 

 have seen, are Miil- 



lerian v ducts. In the Fm 908 _ Female organs of Lepidosteus (A) and Amia 



Salmonida, and the ^^ 5 gSg^ ( ijL^ 



Eels OViducts are bladder ; ovd." peritoneal aperture ; ovy. ovary ; p. peri- 

 l~ ~J 4.1* toneum ; u.g. ap. urinogenital aperture; ur. ureter. (.4, 



absent, and the OVa aft er Balfour and Parker ; B, after Huxley.) 



are discharged by 



genital pores, which are probably to be looked upon as degenerate 

 oviducts. True abdominal pores are present in Ganoids and in some 

 Physostomi. Most Teleostomi are dioecious, but Serranus, one of 

 the Perch family, is hermaphrodite and self -impregnating ; Chryso- 

 phrys is hermaphrodite and successively male and female ; and there 

 are many well-known species, such as the Cod and the Herring, which 

 exhibit the hermaphrodite condition as an occasional variation. 



