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



simply cleaned and not detached, this shows, however, in its proper con- 

 dition as a simple ridge of this lachrymal aponeurosis. Above and 

 below the level of the rictus palpebrarum this lachrymal aponeurosis 

 is continued outwards into the broad ligament of the eyelid, which is 

 attached along the orbital margin, and with whose upper and inner 

 border the trochlea of the superior oblique has originally been struc- 

 turally continuous. From the anterior or facial side of this lachrymal 

 aponeurosis the palpebral and ciliary parts of the orbicularis palpe- 

 brarum are attached, from the posterior or orbital side the musculi 

 lachr i/males (figs. 29, 30). 



The grooved portion of the lachrymal bone is frequently traversed 

 by very many fine holes. These are present even in very young 

 states of the bone (fig. 1), and are even more distinct in the fourth 

 month than in the bone of later age. Sometimes, however, this part 

 of the bone remains quite cribriform (fig. 26), a condition never found 

 in the orbital part, which may have a few vascular holes or absorption 

 foramina, but which I have never found uniformly perforate. 



The inner surface of the young lachrymal bone is covered with 

 a very thin vascular periosteum, which separates it from the ethnioidal 

 cartilage or bone. As age advances, this becomes with difficulty 

 separable, and the underlying ethmoidal lamellae become thin and 

 finally become absorbed in parts ; two lachrymo-ethmoidal cells, 

 superior and inferior, become thus in the adult bounded by this bone 

 externally, and the partition ridge of the ethmoid sometimes becomes 

 ankylosed to the corresponding strengthened ridge of the lachrymal 

 bone. In front of the superior ethmoidal cell, the lachrymal bone in 

 about 60 per cent, is for a short space in contact with the narial 

 mucous membrane, and in about the same proportion the posterior 

 inferior angle forms the outer boundary of that part of the infun- 

 dibulum into which the anterior ethmoidal cells open. The mucous 

 membrane which touches the bone is inseparable from the periosteum, 

 and is covered with ciliated epithelium. The superior lachrymo- 

 ethmoidal cell opens into the infundibulum external to the middle 

 spongy bone, and above and behind the opening of the antrum. The 

 inferior opens lower down and farther forward into the same passage, 

 close to the "opening of the antrum. In old persons the superior 

 lachrymo-ethmoidal cell extends backwards under the os planum. 



The anterior margin of the uncinate process of the ethmoid articu- 

 lated with the hollow of the crista in about 72 per cent, of the 

 specimens. 



VIII. Six separate ossicles occur around the margins of the lachry- 

 mal bone. These are 



1. Ossiculum ethmo-lachrymale superius. 



2. Ossiculum ethmo-lachrymale inferius. 



3. Ossiculum canalis naso-lachrymalis. 



