234 Prof. A. Macalister. Notes on the Varieties and 



D. Carino-hamate forms. 



A. In the normal lachrymal the two lamellae, orbital and lachrymal, 

 which unite at the crista, form an angle which is not far from a right 

 angle, but in those of this first variety the two parts are so nearly 

 on the same plane that the crest is obsolete. This condition is rare, 

 I found it only in twelve bones, mostly of old persons. There is no 

 prolongation of the bone into the nasal canal, and the lower edge of 

 the bone ends opposite the confluence of the nasal duct and lachrymal 

 sac, that is, opposite the lower valve of Beraud ("Gaz. Medicale," 

 1851). Coexisting with this I have never found any separate ossicle 

 nor any imperfect suture, and five of them at least were fenestrated 

 with absorption holes. 



B. The second or simply carinate forms are commoner, and vary in 

 detail of development from those in which the orbital face of the bone 

 shows a slightly ridged convexity below to those in whom the surface 

 is marked by a strongly projecting ridge at the confluence of the 

 grooved and the posterior lamella. In ten out of thirty-six such 

 bones the crest was continuous from above downwards, in twelve it 

 was rounded for the upper third, in nine for the upper half, while in 

 five it was quite obsolete above. Of those in which it was continuous 

 three had a well-marked spur of the crest in the upper part of its 

 middle third, the surface behind which I have found giving attach- 

 ment to the upper ascending fibres of the musculus lachrymalis 

 posterior of Henke (" Archiv fur Ophthalmologie," iv, 270). In none 

 of these was the crest prolonged into a point below, but it ended by 

 its lower border coming into contact with the crista lachrymalis 

 of the maxilla. This form seldom coexists with anomalous sutnration, 

 was not uncommonly fenestrated or foraminated, sometimes ankylosed, 

 and the edges when free were generally uneven. 



C. The third form is the commonest among European skulls. I 

 have found it in over 50 per cent, of British lachrymals, and in 42 per 

 cent, of all examined. In most of these bones the crest becomes 

 gradually more acutely elevated as it descends, and ends in a sharp 

 point which overlies the edge of the maxilla. The lower edge of the 

 bone close to the hamulus splits into two lamellae, an outer which 

 becomes continuously articulated with the orbital floor of the maxilla, 

 an inner continuous downwards into the processus turbinalis, and for- 

 ward into the processus lachrymalis, the latter of which usually comes 

 in contact with the upper and outer edge of the processus hamatus 

 minor, and the anterior edge of the unciform process of the ethmoid. 

 The surface between these lies on the maxilla, but is sometimes, by 

 the absorption of the intervening lamella of bone, brought in contact 

 with the mucous lining of the opening of the antrum maxillare. 



In rather more than 12 per cent, the apex of the crest where it 

 touches the maxilla points directly to the inner end of the sutura 



