244 Proceedings of the Royal Physical Society. 



division of the chromosomes, or, in less specialised cases, of 

 the chromatin, without the formation of an equatorial plate 

 (Fig. 15). 



There is, it appears to me, strong presumptive evidence 

 that this form has a flagellate stage, very probably in some 

 invertebrate host. The features which suggest this are the 

 eosinophile body and the centrosome, and the absence appar- 

 ently of schizogonous stages, which form so conspicuous a 

 feature in Ha^mogregarines and Halteridia proper. 



The occurrence of the parasites here mentioned is as 

 follows: — Out of ten plaice (four of which were large, 

 freshly caught specimens) four were infected with the 

 endocorpuscular form ; two of these infected animals 

 showed the large trypanosome. Out of eight flounders 

 examined, one showed infection with the endocorpuscular 

 form and one with the trypanosome. Unfortunately the 

 films made from this last specimen were very badly fixed, 

 and I cannot make certain as to the presence of the endo- 

 corpuscular parasite. 



I do not wish, at the present time, to assert that the 

 endocorpuscular form has anything to do with the trypano- 

 some ; the discrepancy in size is an a priori argument against 

 the probability of such a relation. It may very possibly be 

 a case of double infection. However, it is interesting to 

 find the two forms in the same host. 



5. Trypanosoma raise. 



MM. Laveran and Mesnil {Trypanosomes et Trypano- 

 somiases. Paris, 1904) described a trypanosome which they 

 had observed in the blood of various rays. Three specimens 

 of Baia microcellata which I examined in the end of March 

 1906 at the Millport Marine Station were found to be infected 

 with a trypanosome, which agrees with that described by the 

 above observers, with the exception of two points, namely, 

 the length of the body behind the blepharoplast and the 

 construction of the nucleus. In the individuals which I 

 observed, the part behind the blepharoplast is regularly much 

 longer than in MM. Laveran and Mesnil's figure. The 



