133 



of FUar'uv in the abdomen of these fishes ; the Filarics being those 

 which of all the species of worms occurring in serous cavities most 

 closely resemble the Eel in form. Mr. Yarrell was inclined to doubt 

 that Eels are viviparous from several circumstances. The species 

 are known to be most prolific: viviparous fishes, on the contrary, 

 l)roduce but few young at a time, and these are of considerable size 

 when first excluded. In illustration of this latter fact, British spe- 

 cimens of the viviparous Blenny {Zocrces viviparus, Cuv.,) and of its 

 young as expelled from the parent fish by pressure, were exhibited. 

 Jn some Eels examined in September the ova in countless thousands 

 vi^ere distinctly apparent under a lens of very moderate power, 

 although these ova would not be matured till January : the sexual 

 organ, moreover, of an Eel taken in February exhibited the ap- 

 pearances common to that part in female fishes that had recently 

 deposited their ova. Mr. Yarrell stated that comparative exami- 

 nations made at this time of the year upon the two most common 

 species o? Eels of our rivers and lakes, showed the sexual organs of 

 the sharp-nosed sort {Anguilla aciitirostris) to be in a much more 

 forward state than those of the broad-nosed Eels (Angtdlla lati- 

 rostris). Skeletons of both species were exhibited, showing the 

 most obvious differences in the size and character of the bones of 

 the head and vertebrce ; those of the broad-nosed Eel being nearly as 

 large again as the same parts of the other species in examples of 

 the same length. 



By some authorities both Eels and Lampreys have been stated to 

 be hermaphrodites. 



Mr. Yarrell exhibited preparations of the two sexes distinct both 

 in the Lamprey and Lampern, at the time they were about to de- 

 posit their ova and milt; and gave the following account of his in- 

 vestigation of this subject. 



" The common river Lampern {Petromyzonjluviatilis, L.) was ob- 

 tained and examined every week from March to the middle of May. 

 Up to the 19th of April more females than males were taken ; but 

 after this period, the females being nearly ready to deposit their 

 roe, the males were most numerous, in the proportion of two to one. 

 All the females taken about the 26th of April were in a state to de- 

 posit their roe ; and the milt of the males, now become fluid, passed 

 in a stream from the sheath behind the anal aperture on making 

 slight pressure upon the abdomen. By the 10th of May nearly the 

 whole of those examined had deposited their spawn. The males 

 were entirely void of any appearance of milt, and the females at this 

 time might be mistaken for males that had not spawned. The gela- 

 tinous matrix of the ova appeared swollen and of large size ; and 

 close examination showed the ruptured membrane and extravasated 

 blood produced by the separation of the ova, with here and there 

 an occasional ovum still adhering. The kidneys (which have been 

 mistaken for the male sexual organs) were notobserved to undero-o 

 any alteration either in size or appearance during a long series *of 

 examinations. The males could be distinguished from the females 

 externally by tlieir larger respiratory apparatus and lips. 



