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Show 208 DR. R. W. SHUFELDT ON [Apr. 1, noteworthy way from the arrangement of the olfactory organ in the Lacertilia generally. Jacobson s Organ appeared to be not as large, comparatively, as it has been found to be in some forms, as in Lacerta viridis for instance ; it is, however, well-developed, and, as stated in a former paragraph, connects by means of a special tubular canal with the oral cavity, opening upon the roof of the mouth, anterior to the posterior narial aperture. As for the olfactory organ itself it exhibits, as usual, an antero-external and postero-internal chamber, which are connected with each other by means of a mid-passage. The postero-internal or true olfactory chamber presents for our examination a large, semi-rolled turbinal bone springing from its outer wall. This is covered with tbe usual mucous membrane, which supports the terminal ramifications of the nasal nerve. Belying, as I do, upon the drawings made by Parker, Hoffmann, and others, which are before me, of the nasal chambers of Lacerta viridis, I am of the opinion that Heloderma differs from that form in these parts in that we find in the true postero-internal nasal cavity of the latter reptile a large turbinated, cartilaginous scroll hanging from, and at the same time attached to, the roof of the chamber in question. Externo-laterally this is connected with the lateral turbinal, the lining membrane passing from the one on to the other. IX. NOTES ON THE ANATOMY OF THE EVE. M y examination into the structure of this organ was by no means exhaustive, and only sufficient to bring the following points to my notice. Both eyelids seem to enjoy the usual movement of opening and closing, rather more especially the lower one. The aperture between them is horizontal. Small dermal tubercles fringe the margins of these eyelids, and somewhat larger ones cover their external surfaces. A very delicate tarsal cartilage is developed in the lower lid, but any such structure appears to be entirely absent from the upper one. By the aid of a lens of some power I succeeded in finding the Meibomian glands in the lower lid, where they seem to be best marked. A nictitating membrane is strongly developed, as is its governing tendon. In Heloderma this membrane is placed quite vertically, and in a state of rest is found covering the antero-internal part of the eyeball. In front of it there is to be seen a semi-elongated, though not large, lacrymal gland, the duct of which ]lasses to open into the buccal cavity. Very much larger than this is the Harderian gland, the body of which in our present subject forms a thick, squarish cushion for the eye, resting upon the floor of the orbit. Anteriorly it becomes smaller, forming a kind of neck, which, crooked outwards upon itself and in contact with the eyeball, opens by a single duct upon the outer surface of the nictitating membrane. This anterior portion of the gland is crossed by the anterior rectus muscle, which holds it against the eye. Little or no fat was found in the orbital cavity. Having their usual origins aud |