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On Bucephalus Ilaimeanus and another Allied Organism. 



By Daniel Moore, M.D. 

 {Read April 23rd, 1875.) 



Before introducing the special subject to which I am to draw 

 your attention to-night, I must state that the filial corrections of 

 my paper, which appeared in the last issue of our Journal, were, 

 through some mistake, not attended to ; they are, however, unim- 

 portant, except in one particular. The second paragraph at the 

 commencement of the Explanation of the Plate ought to have 

 appeared without its last clause, and, to prevent misunderstanding, 

 ought to be as follows : — " The necessity of getting many objects 

 into a small space has obliged me to alter the figures from the 

 original camera lucida drawings, so that although in certain of 

 them there is some approach to micrometric exactness, the 

 magnification may be taken rather as an indication as to what 

 may be seen with certain magnifying powers, than as exact 

 measurements." In the report, also, a mistake has arisen. I am 

 there represented as saying that I never saw the entrance of 

 spermatozoa into ova, whereas my paper is based on the fact that 

 I thought I had seen the entrance of spermatozoa into early 

 stages of ova. Last Friday I was informed that Mr. W. Fell 

 Woods intends to read a paper after me to-night, " On the 

 Relation of Bucephalus Haimeanus to the Cockle." I have, there- 

 fore, made my paper as brief as possible, leaving out matter that 

 I feared might lead to needless repetition. 



In October last I read a short paper before this Club, giving 

 the results of some observations on the Generative Processes of the 

 Oyster, Marine Mussel, and Cockle, which observations had led me 

 to the conclusion that these lamellibranchs were truly monoecious, 

 and I detailed my reasons for so thinking. In the plate, accom- 

 panying that paper, I figured what, I supposed, were the larval 

 forms of the young of these molluscs, giving, however, no reason 



