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



bars which represented the bone were thus the rods representing 

 the cell boundaries. 



III. Variations in outline. No two lachrymal bones are exactly 

 alike, and all intermediate forms between the broadly ovate and the 

 narrow rectangular have been found. The patterns of the borders 

 also are the subjects of great variety, from perfect straightness to the 

 most irregular lobulation. The anterior edge is always the longest, 

 the superior is the shortest, the inferior is usually the least toothed 

 and the most uniform in outline. 



The upper or frontal edge presents three types; it is nearly 

 horizontal in 31 per cent., it rises obliquely from behind forwards to 

 the maxilla in 21 per cent., but in the majority, 43 per cent., it formed 

 an angle salient upwards and forwards, as the upper edge of the orbital 

 portion rises obliquely to the top of the crista, and thence the upper 

 edge of the grooved portion descends rather steeply to the maxilla. 

 In only one bone did the entire border slope downwards and forwards. 



This border is approximately on the level of the top of the 

 os planum in 48 per cent., rises above it in 39 per cent., but lay 

 below it in 13 per cent., the edge is usually denticulated, especially at 

 the top of the crest, and from this forward where it is thicker than it 

 is behind. Ankylosis of this border is not uncommon, to some 

 extent it occurred in one out of every thirty examined, especially in 

 front of the crista. 



A spur of the frontal descended between the lachrymal and the 

 os planum in 34 per cent., but this was only large in one-third of 

 these. A similar frontal spur projects into the maxillo-lachrymal 

 suture in two-ninths of those examined, but was usually slight, only 

 strongly marked in one-fourteenth of these cases of its occurrence. 

 The best marked example of the post-lachrymal spur projected down- 

 wards for 5 millims., and of the pre-lachrymal for 4' 5 millims. 



The upper edge is below the level of the maxillo-frontal suture in 

 all, and this suture usually rises obliquely in front of it, but in some 

 (percentage not recorded) it rises suddenly and steeply. 



The ethmo-lachrymal suture is concave backwards in 50 per cent, 

 straight in 12 per cent., irregular in 36 per cent., convex backwards 

 in 2 per cent., it is more or less toothed in 25 per cent., and seldom 

 ankyloses to the ethmoid (1^ per cent.) The posterior superior 

 angle is usually rounded and seldom projects as far backward as the 

 posterior inferior; in one it sent a process backwards above the 

 ethmoid for 2 millima., a similar condition of the posterior inferior 

 angle undershooting the ethmoid occurred to a marked extent in 

 2 per cent., and to a slight extent in 14 per cent. A slight maxillary 

 spur projects between the ethmoid and os planum in 14 per cent., but 

 is only sharp and strong in 3 per cent. The anterior edge is usually 

 irregular and convex forwards, seldom straight l per cent.) or 



