132 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 



of glial elements could be made out in the tissues of the 

 tumour. There were no traces of similar growths in 

 other parts of the body, in the pseudobranch, for instance, 

 or in any part of the gill-system, so it does not appear 

 likely that the neoplastic cells were conveyed to the eye 

 in the blood stream from other parts of the body. Of 

 course, the peculiar vascular arrangements of the eye — 

 the ophthalmic artery originating in the pseudobranch, 

 and the choroid gland, suggested such an origin for the 

 tumour, but it is probable, I think, that the growth is a 

 primary one. 



9. Ectasia of the Sensory Canals of Raia clavata with 

 intra-cystic Myxofibromata. 



The head portion of a large Ray, sent to me by Mr. 

 Bailey, presented a most peculiar appearance on account 

 of the presence of large vesicles both on the dorsal and 

 ventral surfaces. On feeling these vesicles with the 

 finger it was apparent that they contained some solid 

 growths, but here and there they were soft, the walls were 

 thin and transparent and they contained only liquid. 

 Noticing the form of the vesicles more closely, it was seen 

 that they were symmetrically disposed on both sides of 

 the middle line of the head, and a curved line drawn 

 along their median parts corresponded very closely to the 

 direction of the sensory canals in a normal fish. The 

 vesicles are, in fact, the cephalic sensory canal system 

 dilated throughout its entire course, but with constrictions 

 here and there which confer on it the peculiar vesiculated 

 appearance. 



Plate IV is the reproduction of a photograph of the 

 ventral surface of the head, and shows, on the right (of 

 the photograph), the untouched condition of the canals, 

 and on the left, the cavities cut open. If this is com- 



