Royal Society, 51 



3. " Observations on the Torpedo, with an account of some addi- 

 tional experiments on its Electricity." By John Davy, M.D., F.R.S., 

 Assistant Inspector of Army Hospitals. 



The first part of this paper is occupied by an investigation of the 

 circumstances attending the foetal development of the Torpedo. In 

 the first stage of embiyonic growth u^hich the author had an oppor- 

 tunity of observing, when the embryo was Jibout seven tenths of an 

 inch in length, it had neither fins nor electrical organs, nor any ap- 

 pearance of eyes -, it exhibited short external branchial filaments, not 

 yet carrying red blood 3 and theie vi^as a red spot in the situation of 

 the heart, communicating by red vessels in the umbilical cord with the 

 vascular part of the egg. There is no membrane investing the foetus, 

 as is the case with some species o( Soualif nor any fluid in the uterine 

 cavity 3 neither could the author find any urea or lithic acid in that 

 cavity. By taking the mean of many observations, it appeared that 

 the weight of the egg, betore any appearance of the embryo, is 1 82 grs., 

 and after iis appearance, including the weight of the latter, 177 grs.; 

 while the weight of tlie mature fish is about 479 grs. ; showing an 

 augmentation of more than double. Ttius it differs remarkably, in this 

 respect, from the foetal chick, which at its full time weighs consider- 

 ably less than the original yolk and white from which it is formed. 

 No communication can be traced between the foetus of the Torpedo 

 and the parent, through the medium of any vascular or cellular struc- 

 ture ; and the stomach of the former is always found empty. Hence the 

 only apparent source of nourishment is absorption from the surface ; 

 and the author states his reasons for believing that the branchial fila- 

 ments are the principal absorbing organs, the materials they receive 

 being chiefly employed in the construction of the electrical organs, 

 while those which enter into the composition of the body generally 

 are absorbed by the general surface of the foetus. The author is led, 

 from his researches, to the conclusion that the mode of reproduction 

 in the Torpedo is intermediate between the viviparous and the ovo- 

 viviparous. 



In the second part of the paper, the author discusses the question 

 as to the number of species of the genus Torpedo existing in the Me- 

 diterranean J and concludes that there are only two, viz. the Ochiu- 

 tella and the Tremola. 



4. *' Appendix to a former Paper on Human Osteology*." By Wal- 

 ter Adam, M.D. Communicated by Dr. Prout, F.R.S. 



This appendix contains linear representations of various dimen- 

 sions of the bones of the human body, both male and female, with a 

 view to facilitate the comparison of the human frame with that of 

 other animals, and reduce it to definite laws. The author states that 

 many of the rectilinear dimensions of human bones appear to be mul- 

 tiples of one unit, namely, the breadth of the cranium directly over 

 the external passage of the ear ; a dimension which he has found to 

 be the most invariable in the body. No division of that dimension 



* An abstract of Dr. Adam's former paper was given in Lend, and Edinb. 

 Phil. Mag., vol. iii. p. 457. 



Third Series. Vol. 6. No. 31. Jan. 1835. I 



