Royal Society. 65 



The author remarks, that observers in their endeavours to reach 

 the ultimate structure of the muscular fibril have actually gone too 

 far, and reached a later generation, — mistaking for the fibril a row of 

 quadrilateral particles, the mere elements thereof. These particles, 

 he observes, are known to be alternately light and dark in alternate 

 order ; they give origin to the term spirals ; and for this purpose 

 the dark particles undergo what observers have entirely overlooked, 

 division and subdivision, which changes he has figured in Muller's 

 Archiv, 1850. The preparation in which he has again met with 

 the subdivision into four is still, the author states, in his possession 

 for demonstration to others. 



2. " On the penetration of Spermatozoa into the interior of the 

 Ovum ; a Note showing this to have been recorded as an established 

 fact in the Philosophical Transactions for 1843." By Martin 

 Barry, M.D., F.R.S., F.R.S.E. 



Referring to a statement by Dr. Nelson, in a paper " On the re- 

 production of the Ascaris Mystax" that the investigations in that 

 paper " appear to be the first in which the fact of the penetration of 

 spermatozoa into the ovum has been distinctly seen and clearly 

 established in one of the most highly organized of the Entozoa," 

 the author of the present communication remarks, that when Dr. 

 Nelson made this statement he was evidently not aware of what had 

 been published on the subject. In proof of this Dr. Barry refers to 

 his own paper, entitled " Spermatozoa observed within the Mammi- 

 ferousOvum" (Phil. Trans. 1843, p. 33), in which he states that 

 he had met with ova of the Rabbit containing a number of sperma- 

 tozoa in their interior; and to the Edinburgh New Philosophical 

 Journal for October 1843, which contains a drawing in which seven 

 spermatozoa are represented in the interior of an ovum, besides the 

 statement that in one instance he had counted more than twenty 

 spermatozoa in a single ovum. In conclusion he remarks, that Dr. 

 Nelson merely added a further confirmation in ova of an entozoon, to 

 what his own researches on mammiferous ova had enabled him to 

 record as an established fact nine years before. 



April 7. — A paper was read, entitled " Observations on the Ana- 

 tomy of the Antennae in a small species of Crustacean." By John 

 D. M c Donald, M.D., Assistant Surgeon to H.M.S.V. Torch. 



The little crustacean which is the subject of this paper was taken 

 in considerable numbers in the voyage from St. Vincent to Rio Ja- 

 neiro. There are several anatomical peculiarities mentioned, but 

 the most remarkable is the structure of the right antenna of the 

 male. These organs are in the female perfectly symmetrical, and 

 resemble that of the left side in the male ; and although in the very 

 young state of the latter sex the right antenna differs but little in 

 external appearance from the left, yet the peculiar hypertrophied 

 condition of the modified segments in the corresponding organ of 

 the adult male is to be distinctly traced in a rudimentary state. 



As the animal lives in the open ocean, none of the limbs are 

 adapted for walking ; but when placed in a vessel of sea- water, they 



Phil. Mag. S. 4. Vol. 6. No. 36. July 1853. F 



