340 Dr Eschricht*s Inquiries concerning 



I had a favourable opportunity of observing in the Bothrioce- 

 phalus punctatus, so extremely frequent in the Cottus scorpius. 

 During mid- summer, in almost all their joints, the uteri are 

 filled with ova. At the same time individual worms without 

 heads may be sometimes found in the lower part of the intes- 

 tine. These are about to be expelled ; for in other circum- 

 stances, all specimens of Bothriocephalus punctatus adhere by 

 the fore-part of the head to the mucous surface of the appen- 

 dices pyloricae. The want of the head in the expelled indivi- 

 duals makes it probable that they have left it behind in its 

 habitual place, and this supposition is much strengthened by 

 the above-mentioned observation of a number of heads adhe- 

 ring to the mucous surface of the appendices pyloricae between 

 other worms of very different lengths. The heads left behind, 

 after the expulsion of 'all the joints, are about to generate a 

 new series of joints of the most perfect kind ; and this in the 

 following way. The joint next the head is soon divided by a 

 transverse fissure into two, each of which repeats the same 

 process as soon as it is somewhat grown. The repetition of 

 this imperfect transverse division is marked, more or less, in 

 all the Certoidea at the joints near the head, the fissures of 

 later date appearing as more indistinct subdivisions between 

 these earlier and deeper fissures. Whilst the joints multiply 

 in this way, they increase in size in the same proportion, and 

 so of course remove the joints from the head. But at a cer- 

 tain distance from the head this mode of subdividing ceases, 

 and the whole nutritive power is applied to the development 

 of the organs of generation. During the winter, the Bothrio- 

 cephalus punctatus, always adhering firmly to the mucous sur- 

 face of the appendices pyloricae, is increased to its full length, 

 the uteri and most of the other generative organs being formed, 

 but no ova have yet appeared. Up to this period, the develop- 

 ment of the generative organs is scarcely to be considered as 

 disproportionate, and this is by far the best time for the exa- 

 mination of the other systems ; a vascular system may now be 

 seen ramified in innumerable anastomosing branches ; a system 

 of vesicles covers the skin all over ; and innumerable primitive 

 cells with nuclei and nucleoli, and granules of a very minute 

 size, are diffused throughout every part of the interior. At the 



