230 Prof. A. Macalister. Notes on tJie Varieties and 



frontal behind ; a small lacuna closed by membrane completing the 

 boundary. In the second instance the right groove is entirely 

 formed by the maxilla, the nasal process of which is expanded 

 backwards (fig. 20, x) into a flat plate behind the crista lachrymalis 

 posterior (y), which also is maxillary. This plate articulates above 

 with the frontal, and posteriorly with the prolonged orbital plate of 

 the maxilla, which meets the frontal in a suture between the back of 

 the nasal lamella and the front of the os planum. On the left side 

 the lobe of the nasal process articulates by suture with the ethmoid, 

 and below it there is a small lacuna (fig. 28, lac.), which may possibly 

 have been filled by an ossicle. In this skull all the sutures are 

 distinct, so the variety is not due to synostosis. 



Systematic writers speak indefinitely of such cases, and Krause 

 (" Handbuch," III, p. 71) says that it occurs in 8 per cent, of crania, 

 but does not specify from what number of crania his percentage is 

 derived. This is not my experience, and I believe it is not safe to 

 make museum crania* the basis of such observations, as I have more 

 than once seen instances of rudimental lachrymal bones in which the 

 diminutive bone fell out in the course of handling. Metzger also 

 records cases of absence (" Curat. Chirurg. Fistula Lachrymalis, Hist. 

 Critica," Miinster, 1772, p. 66). 



II. Rudimental states of the bone are very common, and I think it 

 probable that many of the so-called instances of deficiency are really 

 examples of some one or other of these conditions. I have notes of 

 five forms of rudimental bone. 



at. Development of an orbital plate alone, terminating at the crista 

 lachrymalis, and with consequent exclusion from the lachrymal 

 groove which is formed of the nasal process of the maxilla alone. 

 This I have thrice seen, all in unsymmetrical examples ; the bones in 

 each case were simple scales of small size, corresponding to the 

 hinder portion of the orbital plate of the normal bone, in one case 

 resembling the superior ethmo-lachrymal ossicle to be after de- 

 scribed. 



In several crania in which the lachrymal bone had been broken or 

 had fallen away, I have seen the largely developed lachrymal lamella 

 of the nasal process of the maxilla which, in the perfect cases, was 

 associated with this variety, and hence probably they were instances 

 of the same condition. A similar arrangement is described by Henle 

 (" Knochenlehre," p. 193) as occurring in an Italian skull. 



ft. Development of two detached ossicles in place of a normal bone. 

 This I have once found in a Negro skull. The lower of the two 

 ossicles was the larger, and formed a small part of the lachrymal 



* Another reason why museum crania form an unsafe basis for statistics is the 

 obvious one that they are to a large extent selected on account of their exhibiting 

 peculiarities. 



