226 Dr. W. H. Ransom on the Ovum of Osseous Fishes. [June 21, 



At a is the vagina, continued as an indistinct tube to b, which I suppose 

 to be the seminal vesicle ; immediately beyond this is a dark mass (o) con- 

 taining spherical, highly refractive bodies ; this is the ovary. On either 

 side and in front of this are the yelk-forming glands (e), two somewhat 

 indefinite lobular organs apparently communicating with the vagina in 

 front of the seminal vesicle. At c and d are the globular testicles; / is 

 the rudimentary vas deferens. Running forwards from the vagina is another 

 narrower tube g, which passes quite to the anterior end of the segment, 

 where it becomes at first shghtly dilated (fig. 5, u'), and afterwards en- 

 larged into the head of the uterus ; a large spherical sac full of ova is 

 readily seen with the naked eye in many sexually mature segments (fig. 

 4, ut.). The greater part of the body of this tube also becomes enlarged 

 into the uterus (u, fig. 5), but I think that the hinder part continues 

 tubular, and probably constitutes the ** wide cavity " leading from vagina 

 to uterus, described by Leuckart. In fig. 5 there is some appearance of 

 this tube continued backwards from u (a, fig. 5), but I cannot follow it to 

 any communication with the vagina (va.). The same is true in this specimen 

 of the ovary (ov.) and seminal pouch (s.p.). The vitelligene glands (e, fig. 4) 

 have disappeared in fig. 5, and the ovary has become less distinct, but the 

 seminal pouch has developed somewhat, while in fig. 6, taken from a 

 sexually mature segment, the latter organ is still plainer ; the canal of the 

 vagina has elongated, and shows besides the seminal pouch a smaller dila- 

 tation (a, fig. 6) nearer the orifice. In none of the mature segments 

 have I been able to make out any communication between the vagina and 

 uterus, either in front of or behind the seminal pouch. 



Although Dr. Cobbold has succeeded in rearing a variety of tapeworms 

 from their respective larvse, the Tcenia echinococcus has not hitherto been 

 reared in this country. 



The importance of this creature in its pathological relations, and the 

 desideratum of more information as to its anatomy, have induced me to 

 place the foregoing facts on record. In conducting the investigation I 

 have taken every precaution to prevent the escape and distribution of the 

 ova and their contained proscolices. 



EXPLANATION OF PLATE.— Fig. 5. 



va. Vagina. a. Tube (?) leading from uterus to vagina. 



ov. Ovarium. t. Testicles. 



s. p. Seminal pouch. v. d. Vas deferens, 



21, tc'. Uterus partly developed. c. p. Cirrhus pouch. 



VIII. " Observations on the Ovum of Osseous Fishes.^' By W. H. 

 Ransom, M.D. Communicated by Dr. Sharpey. Received 

 June 21, 1866. 



(Abstract.) 



In this paper the author has communicated the details of observations 

 of which the principal results were stated in a short paper published in the 



