PHILOSOPHICAL TRANSACTIONS. 
XIX. On the Structure, Functions, and Homologies of the Manducatory Organs in 
the Class Rotifera. By Philip Henry Gosse, Esq. Communicated hy Thomas 
Bell, H.P.R.S., Pres. L.S. 
Received January 5, — Read February 22 and March 1, 1855. 
1. An examination of the whole alimentary system in the class Rotifera would in- 
clude — The buccal funnel ; the manducatory apparatus, with its muscular bulb and the 
muscular bands by which it is retained in situ ; the salivary glands ; the oesophagus ; 
the pancreatic glands ; the stomach ; the hepatic follicles ; the cseca ; the intestine ; 
the rectum ; and the cloaca. Of these, however, the manducatory organs will occupy 
my principal attention; and I shall endeavour to trace them throughout the class; 
and to show, that the various forms which they assume can all be reduced to a com- 
mon type. I also propose to inquire, what are the real homologues of these organs 
in the other classes of animals ; and what light we can gather, from their structure, 
on the question of the zoological rank of the Rotifera. 
2. Considering the attractive appearance which the Wheel-animals present, and 
the facilities which are afforded for their investigation by their abundance — since 
they are found in great variety in almost every river, lake, pond, and ditch, — it is 
rather remarkable that they have been so little studied. 
3. The foundation of our acquaintance with the organization of the Rotifera was 
broadly laid by Professor Ehrenberg, in the ‘Transactions of the Berlin Academy,’ 
as early as 1830; and in 1838 he published his ‘ Infusionsthiercheu,’ a work which, 
in spite of its mistakes and deficiencies, must be considered a magnificent monument 
of industry and scientific acumen. It is true, Leeuwenhoek, Baker, Joblot, and 
other early microscopists had figured a few species ; and Rosel, Schaffer, and espe- 
cially Muller, had attempted to resolve the internal anatomy of some ; but all that 
had been accomplished amounted to little more than vague guessing, when Ehren- 
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