4 ON THE BURSA FABRICII IN BIRDS, 



end with the crypts of shallow glands, \vhich also run down its sides. 

 That it is a modification of the bursa Fabricii cannot be doubted." 



The disposition of the parts described aboye seemed peculiar enough 

 to be worthy of further investigation ; with that end my kind friend 

 Prof. G-arrod requested me to undertake a series of observations on the 

 bursa in other birds, in order to throw further light on the structure of 

 this organ, and to discover what characters, if any, it afforded for classi- 

 P. Z. S. 1877, ficational purposes. The ample materials of the Prosector's department 

 p. 305. k ave gj ven me opportunities for examining this organ in a considerable 

 number of species of birds of various orders ; and though I regret to say 

 my investigations have not turned out so satisfactorily as regards taxono- 

 mic characters as I had hoped, I venture to bring such results as I have 

 obtained before the Society this evening. As the subject of the bursa 

 Fabricii has hardly attracted any notice in this country since the days of 

 Harvey, I have added to my own notes a brief resume of the most im- 

 portant observations and opinions as regards its structure and functions 

 that have been brought forward by foreign anatomists. 



The organ in question seems first to have been noticed by the naturalist 

 whose name it bears, Fabricius of Acquapendente. In his treatise ' De 

 formatione ovi et pulli ' *, p. 5, he says : " Tertium quod in podice est 

 adnotandum est duplex vesicula quse in ima ejus parte ad os pubis 

 supereminet, et conspicua exteriorque apparet, simulatque uterus jam 

 propositus conspectui sese offert : quse cum sit pervia, ita ut ab ano ad 

 ipsum uterum et ab utero in ipsam, ut puta superius, infra foramen pateat, 

 ex altero autem extreme clausa sit, hunc existimavimus esse locum, in 

 quern gallus semen immittit porrigitque ut inibi servetur." From this 

 and other passages in his works it is clear that he considered its function 

 that of a receptaculum seminis in the female ; its use in the male, on such 

 a theory, he does not explain. Harvey, in his work * De Generatione 

 Animalium ' (London, 1651), as quoted in the Sydenham Society's trans- 

 lation of his works (1847, p. 183), refutes Fabricius's ideas on this point. 

 " The foramen into which Fabricius believes the Cock to inject his fluid, 

 is discovered between the orifices of the vulva and the rump. I, however, 

 deny any such use to this foramen ; for in young chickens it is scarcely 

 to be seen, and in adults it is present indifferently in males and females. 

 It is obvious therefore that it is both an extremely small and obscure 

 orifice, and can have no such important function to fulfil ; it will scarcely 

 admit a fine bristle and needle, and it ends in a blind cavity ; neither 

 have I ever been able to discover any spermatic fluid within it, although 

 Fabricius asserts that this fluid is stored up there even for a whole year, 

 and that all the eggs contained in the ovary may be thence fecundated, 

 as it is afterwards stated." Harvey, however, fell into error in asserting 



* Hieronymi Fabricii ab Aquapendente opera anatomica. Patavii, 1625. 



