THE 



MONTHLY MICROSCOPICAL JOURNAL. 



APRIL 1, 1870. 



I. — Description of some peculiar Fislis Ova. 

 By W. B. Carpenter, M.D., F.E.S. 

 (Read hefore the Eoyal Microscopical Society, March 9, 1870.) 

 Plate XLV. 



More than thirteen years ago, when dredging in Lamlash Bay, 

 Arran, in the month of August or September, I brought up from 

 a depth of thirty or forty fathoms a fragment of a Bivalve Shell, on 

 the internal surface of which I noticed some minute bodies, whose 

 appearance under a hand-magnifier was so unusual as considerably 

 to perplex me. On submitting them to a higher magnifying power, 

 it at once became obvious that they were the Ova of a Fish ; for 

 some of them contained embryoes in a state of advanced development, 

 whilst from others the mature embryoes were in the very act of 

 escaping, others, again, being entirely empty. Fui'ther examination 

 disclosed some very curious features in these Ova, which I should have 

 described long since (as Prof. Kolliker, to whom I showed them at 

 the time, urged me to do), if I had been able to find any clue to 

 their parentage. But having neither again met with them, nor been 

 able to obtain any information from the Lamlash fishermen that 

 could help me to determine this point, I deem it better to put on 

 record the results of my observations, in the hope that some other 

 Naturalist may be able to complete them by the discovery of the 

 Fish by which these ova are produced, and by the study of the earlier 

 stages of the development both of the ovum itself and of the embryo 

 which its fecundation generates. 



The peculiarities which I have to describe have reference (1) to 

 the Shape of the Ova ; (2) to the mode of their Attachment to the 

 surface of the Shell ; (3) to the position and remarkable distinctness 

 of the Micropyle. 



1. So far as I am aware, the Ova of Fish (save those of the Pla- 

 giostome family) have been hitherto described as either spherical or 

 ellipsoidal. These ova, on the other hand, are nearly hemi-eUip- 

 soidal; having one surface plane and the other convex (Plate XLV., 

 Figs. 1, 2). The plane surface is an ellipse, the longitudinal diameter 



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