ON THE RELATION OF Bucephalus TO THE COCKLE. 59 



The recorded notes of my observations extend to nine only of 

 the months of the year. In neither year do I appear to have made 

 any examinations in September, October, or January. 



Each statement now advanced I have verified by extracting from 

 my note books the date of at least one of the observations on which 

 it is founded. 



It was during my investigations into the development of the eggs 

 in the Oyster that, for purposes of comparison, I opened a Cockle 

 on the 14th June, 1872. I therefrom obtained a mass of seem- 

 ingly orange-coloured tubing, which lay amongst the muscles and 

 around the liver and other organs of the mollusc. It was seen to 

 be occasionally branched, to be distended in some places, and con- 

 stricted in others. 1 When severed there were poured forth, in 

 various stages,. then roughly sketched, the forms of the creature now 

 believed to be Bucephalus Haimeanus. 2 I exhibited it at our local 

 Society, and subsequently, in the spring of 1873, at the Annual 

 Soiree of the Quekett, as a " Marine Parasite," that having been 

 my first impression of its character. I thought I observed a 

 motion of severed parts of the tube, 3 indicating its separate 

 existence as a mother or nurse of this progeny, but, from other 

 observations, it seemed more likely that the movements were only 

 due to the constriction or collapse of the tube upon its evacuation 

 by the bodies contained near tbe fracture, and by the subsequent 

 passage of those higher up, for whom room was thus made. More- 

 over the tube appeared to be continuous and of immense length ; 4 

 portions of the stem were sometimes frequently branched, and I 

 think also the branch was sometimes bifurcated. No one seemed 

 to know anything about it, and possibly through not being shown 

 in my capacity as a member of the Quekett, but only as one of the 

 visitors from a local society, who, I think, formerly did not fare 

 so well in the arrangements made as they now do, it was the less 

 prominent, and scarcely attracted notice. Referring to Diesing, I 

 was thrown off the scent by his making no mention of any parasite 

 in the Cockle. I continued my observations on a large number of 

 Cockles in various conditions during different months, constantly 

 strengthening the idea which soon presented itself, that, instead of 



1 Fig. A. 



2 Fig. H. Only the earlier stages are here shown ; the specimen contained all 

 stages from spheres to well-developed Bucephalus. 



3 June 14, 1872. February 28, 1873. May 20, 1873. 



4 June 14, 1872. 



