294 PROCEEDINGS OF THE CANADIAN INSTITUTE. 
oval in outline; they consist of an aggregation of ocelli. The 
Maxillipedes are broad, lamellate structures, and of comparatively 
large size. Their inner margins meet in the median line, and are 
nearly straight. A short, thick palpus, of three joints, is borne by 
each Maxillipede on its upper and outer margin, in front of which it 
projects. The under-lip is attached to the Maxillipede, and is pro- 
duced externally to it. The second pair of Maxille is flat, foliaceous, 
and of the same breadth throughout. It bears a cap of chitine on 
its upper and inner angle. The inner or first pair of Maxille 
possesses both endopodite and exopodite ; the latter is considerably 
the longer and stouter, and bears five inwardly-curved chitinous. 
denticulations, and its outer border is beset with fine sete. The 
endopodite is composed of two joints, both slender, the upper one 
tipped with two feather-like sete. The Mandibles are strong and 
of considerable thickness, being circumscribed by a horny skeleton- 
and bearing three bluntly pointed teeth at their apex, and patches 
of fine setee on their inner and outer edges. The Labrum, above the 
Mandible, is apparently a paired structure. It protects the oral 
aperture. In structure it is foliaceous, and may be regarded as a 
median growth of the sternum of this region. 
The Thoracic Appendages, seven in number, bear a strong simi, 
larity one to another. They are composed of seven joints, and none 
are chelate. A more exact description of them then followed. 
Of the six abdominal appendages five are concealed under the 
abdomen—the uropods (appendages of the sixth somite) projecting 
behind. The various modifications of these abdominal appendages in 
the sexes then is dwelt upon at some length. 
The uropods are alike in both sexes, and consist of a basal seg- 
ment bearing two rami. 
The President, for Dr. Robert Bell, of Ottawa, read the 
following paper on “ The Mode of Occurrence of Apatite in 
Canada,” by Robert Bell, B.A.Sc., M.D., LL.D., Assistant 
Director of the Geological Survey of Canada: 
The mode of occurrence of apatite in the crystalline rocks of 
Ontario ‘and Quebec, has been a puzzling question to geologists ever 
since the mineral has been known to exist among them in quantities 
of economic value. A number of contributions to a knowledge of 
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