46 HENRY H. LANE. 



it to be an almost bilaterally symmetrical organ, but without any 

 folds or pockets in which the embryos are contained as is the 

 case in Cymatogaster 1 and numerous other species of Embiot- 

 ocidae. During the intra-ovarian development of the embryos, 

 or rather the development of the foetuses within the oviduct 

 of Liicifjiga, the ovarian structure proper or stroma which forms 

 the thick median partition in non-pregnant ovaries, becomes 

 gradually reduced and compressed into a narrow wall (Fig. 5). 

 The stroma is much thickened both dorsally and ventrally near 

 the oviduct (Fig. 4), where the partition is incomplete, but ante- 

 riorly its greatest thickness is near the median plane (Fig. 5). The 

 arrangement of the stroma in each horn of the ovary is as in non- 

 pregnant ovaries (Fig. 6, ov.st.}. 



The single oviduct runs from the caudal end of the ovary 

 proper to open at the urogenital pore. In pregnant females it is 

 widely distended for some distance when the foetuses are well 

 advanced, but in the non-pregnant females it is a rather cylin- 

 drical, thick-walled, muscular tube with numerous folds or laminae 

 on its inner surface, covered with a layer of columnar epithelial 

 cells, 12 fj. in depth. It is not materially different, except as to 

 dimensions, from the ovisac described above. Stuhlmann 2 sim- 

 ilarly found the oviduct of Zoarces to be a tube composed of the 

 same cell-layers as the ovary, with the exception of the " ger- 

 minal " and follicular epithelia. 



VI. HlSTOLOGICAL PART. 



/. The Walls of the Ovary or Ovisac. 



The following system will be used to facilitate cross references 

 to the descriptions of the various ovaries. Each ovary will be 

 referred to by a letter, A, B, C, etc., the meanings of which are 

 as follows : 



A represents a female of the genus Stygicola with a length of 

 95 mm. 



B represents a female of the same genus, but with a length of 

 128 mm. 



C represents a female of the genus Lucifuga, length 87 mm. 



1 Eigenmann, op. cit., p. 418. 



2 Op. cit., p. 10. 



