206 PROCEEDINGS OF SOCIETIES. 



with any specific description, and were told by some of the most 

 eminent British entomologists that our specimens were nothing 

 but starved slieep-ticks, I took one of them up to Oxford at the 

 beginning of last term, when the illustrious entomologist, Prof. 

 Westwood, declared, and was the first to determine, it to be the 

 Argas reflexus, a parasite infesting pigeons, and known on the 

 Continent, but heretofore not recognised in Britain. So our 

 arachnids had probably dropped from these birds, and are cer- 

 tainly to be found rather plentifully crawling about the inside of 

 the base of the cathedral. 



LlTEBAEI AND PHILOSOPHICAL SOCIETT OF MaNCHESTEB. 



Microscopical and Natural History Section. 

 February Wh, 1872. 



Joseph Baxendell, F.R.A.S., President of the Section, in the 

 chair. 



Mr. Joseph Sidebotham, F.E.A.S., called the attention of mem- 

 bers to the origin and spread of typhoid fever, as connected with 

 the germ theory. 



February 2Qth, 1872. 



Joseph Baxendell, P.E.A.S., in the chair. 



Mr. Mark Stirrup exhibited sections of shells of mollusca, 

 showing so-called fungoid growths. He referred to Dr. Carpen- 

 ter's report on shell structure, presented to the meeting of the 

 British Association, in 1844, in which especial mention is made 

 of a tubular structure in certain shells, and he cites the Anomia 

 as a characteristic example. In the last edition of ' The Micro- 

 scope,' Dr. Carpenter withdraws his former explanation of this 

 structure, and now refers it to the parasitic action of a fungus. 

 Mr. Stirrup showed sections of this shell penetrated by tubuli 

 from the outer to the inner layers of the shell, and it is upon the 

 inner layer that the curious appearance of sporangia, with slightly 

 branched filamentous processes proceeding from them present 

 themselves. 



The parasitic view is strengthened by the fact that these 

 markings are not found on all parts of the shell, and are certainly 

 accidental. 



Professor Kblliker maintains the fungoid nature of these 

 tubuli in shells as well as in other hard tissues of animals, as 

 fish scales, &c. 



Wedl, another investigator, considers the tubuli in all bivalves 

 to be produced by vegetable parasites, and that no other interpre- 

 tation can be given. 



