514 



Zoological Society. 



of rain-drops and ripple-marks. The rain-marks appear as if the rain 

 had been driven by a strong wind, and the direction of the impres- 

 sions indicated that the wind blew from the west, a quarter from 

 which violent squalls or thundergusts are still prevalent in these 

 latitudes. 



ZOOLOGICAL SOCIETY. 

 July 26, 1842. — William Yarrell, Esq., Vice-President, in the Chair. 

 The following memoirs were read : — 



" Observations on the Semen and Seminal Tubes of Mammalia and 

 Birds," by George Gulliver, F.R.S. 



It has long been known that the testicles of Birds become much 

 enlarged in the spring, and that the same organs of Mammalia are 

 more or less increased in size at the rutting-season, and in young 

 animals generally as they become capable of reproduction. Professor 

 R. Wagner (' Physiology,' translated by Willis, pp. 23 and 27) has 

 noticed also the enlargement of the seminal tubes of all these animals 

 at the periods above named ; but as I am not aware that we possess 

 any observations on this head sufficiently numerous and precise to 

 be useful for reference and comparison, I am induced to submit to 

 the Society a contribution towards this object, particularly as it ap- 

 pears to me that the condition of the semen and testicles at different 

 periods is an interesting inquiry in relation to the habits and economy 

 of animals. 



During winter the coats of the seminal tubes of Birds are tolerably 

 strong and thick. The increased size of the tubes at the season 

 of procreation arises from the accumulation of semen within them, 

 by which their coats are so much distended and attenuated that they 

 are most easily ruptured, and are much thinner than the correspond- 

 ing parts of Mammalia are at any time. 



In the following table the measurements are all expressed in vul- 

 gar fractions of an English inch*, and where only one fraction is 

 given it denotes the average size. With the exceptions dated No- 

 vember and December, the animals were all examined during the 

 present year, and, unless noted to the contrary, they were adults. 

 In Birds the left testicle, which is commonly somewhat larger than 

 the right, was generally the subject of observation. 



Table of Measurements of the Seminal Tubes, and of remarks on the 

 state of the Semen and Testicles at different seasons. 



* I take this opportunity of remarking, that all my microscopic measure- 

 ments have been invariably given in vulgar fractions of an English inch, 

 however they may have been set up in type for the sake of convenience. 



