223 report— 1846. 



mosal. The malar joins the post-orbital process of the frontal in the Mana- 

 Aus senegalensis, the hippopotamus, the solipeds, and ruminants, some carni- 

 vores and the lemurs ; in the true quadrumanes and man it joins the alisphe- 

 noid, and sometimes also the parietal. 



The presence, form and connections of the malar are much more constant 

 in the class of birds ; where, however, it must be sought for as an indepen- 

 dent bone at an early period. In the young ostrich (fig. 23, 26) it is reduced 

 to the form of a simple, straight, slender style, and coalesces first with the 

 similarly-shaped squamosal (27), and next with the malar process of the 

 maxillary (21"). In the crocodile the malar bone (fig. 22, 26) becomes more 

 developed, and adds the connections with the postfrontal (12) and the ecto- 

 pterygoid (24') to the more constant ones with the maxillary (21) and squa- 

 mosal (27), which alone sustain it in birds. In most of the chelonians the 

 malar presents the same connections as in the crocodile, but is transmuted 

 from a ' long' to a 'flat' bone. It retains the expanded shape in the agama; 

 but in most other lizards it resumes the styloid form ; being broadest, how- 

 ever, in those genera, e. g. Iguana, Thorictes, Tejus, in which it extends from 

 the maxillary to the postfrontal and squamosal ; in the Varani it projects 

 freely backwards, like a styliform appendage of the maxillary, as in the 

 toothless mammalian Bruta, above-cited. 



There is no malar bone in ophidians and batrachians. The lower portion 

 of the tympanic pedicle in the Anoura sends forward a process which joins a 

 backward prolongation of the maxillary : in all other batrachia the lower 

 portion of the tympanic pedicle is restricted to its normal connections and to 

 its function of affording articulation to the lower jaw. With regard, there- 

 fore, to the zygomatic modification of this portion of the pedicle in anourous 

 Batrachia, some may deem it the homologue of the malar ; and, in marsu- 

 pial quadrupeds, the malar actually forms part of the glenoid cavity for the 

 lower jaw : or it may be regarded as the squamosal, which constantly sup- 

 ports the lower jaw in mammals : or it may be viewed as the coalesced homo- 

 logue of both bones : or finally, as a simple modified dismemberment of the 

 tympanic pedicle of the higher reptiles and birds ; effecting a union with 

 the maxillary bone which makes it analogous to, but not, therefore, homolo- 

 gous with, the distinct malar and squamosal in those higher vertebrates. This 

 is a question of special homology on which I am unwilling at present to 

 express a decided opinion : but viewing the inconstancy of the squamosal in 

 reptilia, and its deprivation of the function of exclusively supporting the 

 mandible in all ovipara, I am disinclined to adopt the idea of its sudden resti- 

 tution to that mammalian function in frogs and fishes ; yet, if either of the 

 bones 26 and 27 are to be selected as the homologue of the hypotympanic (28C?) 

 of batrachians and fishes, I should regard the claims of the squamosal to be 

 stronger than those of the malar, which Cuvier has chosen. The further sub- 

 division, however, of the tympanic pedicle in fishes, prepares us, in the as- 

 censive comparison, for the simple division of the pedicle in batrachia, and 

 for recognising in the lower articular portion a vegetative dismemberment of 

 23 in the crocodile. 



The characters and chief changes, in respect of connections and functions, 

 of the squamosal (27) in the mammalia have already been noticed in the dis- 

 cussion of the homologies of other elements of the complex ' temporal bone' 

 in that class. In birds the bone (fig. 23, 27) undergoes the same change of 

 form which has been noticed in the jugal, viz. from the squamous to the 

 styloid. It continues, however, to connect the malar with the tympanic as 

 it does in figs. 1 1 and 12? but it has no connections with other bones. Cu- 

 vier having been led to recognise the squamosal in the mastoid (fig. 23, 3) of 



