Mastax M. ringens, &c. Lord S. G. Osborne and F. A. Bedwell. 177 
cally the conclusions deduced by me from a careful study of the 
astonishing characteristics of the apparatus. I have since corrected 
these conclusions by references to living objects, but I shall begin 
my observations by confining them at &st to the uncorrected im- 
pressions made on the eye and mind by Lord Sydney Gr. Osborne’s 
slides themselves, and introduce the corrected impressions subse- 
quently, for, I think that a principle of observation of consider- 
able importance will be well illustrated by so doing. 
The information to be obtained from these specimens supple- 
ments in several interesting particulars the previous papers on the 
same subject noted below, and especially Mr. Gosse’s well-known 
and important paper * on the manducatory organs of the Botifera. 
A reference to that highly original paper will show the extra- 
ordinary variations discovered by him in the organ in the different 
sections of the Eotifer family, and also the names which he has 
chosen for the different parts of the organ. The organs are sym- 
metrical and bilateral, and consist of a pair of jaws. The teeth 
{unci) work horizontally, and are forced forward from behind by 
handles (manuhria), to which their roots are attached ; these 
manuhria are armed sometimes with mallet heads {mallei), the 
same teeth {unci) are also attached at their points to blades {rami), 
and these rami draw’ the two sets of teeth by the points together, 
and themselves meet or cross each other at one extremity in a hinge 
{fulcrum), which gives them a scissor or tongs-like action, and in 
some cases the teeth work on an anvil {incus). 
Of the figures which accompany this paper. Fig. 1, Plate X., is 
an anatomical diagram of the parts of the mastax of M. ringens. The 
teeth {unci), which I make out to be about fifteen in number, are 
seen below, at gp, having been removed from each jaw ; their points 
of junction with their late supports are expressed in the ease of each 
ramus by the serrated or turreted edges of that organ ; these ser- 
rations in the diagram represent true sockets visible under a high 
power, particularly in the case of the large teeth after the removal 
of the teeth from the ramus.'\ The basket-like organs d d are the 
manuhria, the parts ah c form the rami, f is the hinge, and the 
parts e will be explained subsequently. Fig. 2, Plate X., is a rough 
sketch of the general effect of the organ as seen looking towards the 
hinge, five of the teeth on each side having been removed to make 
the under parts visible. 
Passing on to Fig. 4, Plate X., that figure affords a me- 
chanical illustration to express in cardboard my views of the 
form of the ramus, and I will proceed to explain it. Take a 
thick piece of cardboard and cut from it a portion with an 
* See Williamson on M. ringens, ‘ Quar. Journal Mic. Sci.,’ vol. i. p. 3, 
1853; Gosse on M. ringens, idem, p. 71 ; ‘Phil. Trans.,’ 1856, vol. cxlvi. p. 419. 
t In Rotifer vulgaris these serrations are very distinct. 
