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-interual 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 the usual mucous membrane, 

 which supports the terminal ramifications of the nasal nerve. 



Relying, 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 tur- 

 binal, the lining membrane passing from the one on to the other. 



IX. Notes on the Anatomy of the Eye. 



My examination into the structure of this organ was by no means 

 exhaustive, and only sufficient to bring the following points to my 

 notice. Eoth 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 ex- 

 ternal 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, lacrymnl ghtiid, the duct of which 

 passes 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 eye- 

 ball, 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 and 



