PROCEEDINGS OF SOCIETIES. 169 



November 28, 1855. 

 George Jackson, Esq., in the chair. 

 C. L. Bradley, Esq., Barnsbury Park; E. Grove, Esq., Park- 

 street, Westminster ; E. Cobbett, Esq., 4 Cullum-street ; Mr. H. 

 Williams, Somerset House ; and John White, Esq., Cowes, Isle of 

 Wight, were balloted for, and duly elected. 



Mr. Wenham read a paper on the formation and development of 

 Vegetable Cells (Transactions, vol. iv. p. 1). 



Royal Society. 

 Mr. GossE, " On the Structure, Functions, and Homology of the 



Manducatory Organs in the Class Rotifera.^' March 1, 1855. 

 In this paper the author institutes an examination of the manduca- 

 tory organs in the class Rotifera, in order to show that the various 

 forms which they assume can all be reduced to a common type. He 

 further proposes to inquire what are the real honiologues of these 

 organs in the other classes of aniinals, and what light we can 

 gather, from their structure, on the question of the zoological rank 

 of the Rotifera. 



After an investigation of the bibliography of the class from Ehren- 

 berg to the present time, in which the vagueness and inexactitude 

 of our knowledge of these organs is shown, the author takes up, one 

 by one, the various phases which they assume throughout the whole 

 class, commencing with Brachionus, in which they appear in the 

 highest state of development. Their form in this genus is therefore 

 taken as the standard of comparison. 



The hemispherical bulb, which is so conspicuous in B. amphiceros, 

 lying across the breast, and containing organs which work vigorously 

 against each other, has long been recognized as an organ of mandu- 

 cation ; it has been called the gizzard, but the author proposes to 

 distinguish it by the term mastax. It is a trilobate muscular sac, 

 with walls varying much in thickness, receiving at the anterior ex- 

 tremity the buccal funnel, and on the dorsal side giving exit to the 

 oesophagus. 



AVithin this sac are placed two geniculate organs (the mallei), 

 and a third on which they work (the incus). Each malleus consists 

 of two parts (the manubrium and the uncus), united by a hinge- 

 joint. The manubriuin is a piece of irregular form, consisting of 

 carincB of solid matter, enclosing three areas, which are filled with 

 a more membraneous substance. The uncus consists of several 

 slender pieces, more or less parallel, arranged like the teeth of &, 

 comb, or like the fingers of a hand. 



The incus consists of two rami, which are articulated by a com- 

 mon base to the extremity of a thin rod (the fulcrtmi), in such a 

 way that they can open and close by proper muscles. The fingers 

 of each uncus rest upon the corresponding ?a»iM5, to which they are 

 attached by an elastic ligament. The mallei are moved to and fro 

 by distinct muscles, which the author describes in detail, and by the 

 action of these they approach and recede alternately ; the rami 

 opening and shutting simultaneously, with a movement derived 

 partly from the action of the mallei, and partly from their own 

 proper muscles. 



