658 SKELETON. 



the ribs, then the cranial vertebrae, as verte- of cranial vertebrae, if these ribs be not the 



bra;, must have the ribs also. What other maxillary arches ? * 



cephalic structures, therefore, are there in the Now there happens in./%. 481., between the 



head which may be said to stand as the ribs costiform maxilla (dd*) and thoracic ribs 



Fig. 481. 



x 



A <- 



The human crania-facial and cervico-hyoid apparatus, 



Shelving that the hyoid apparatus relates to the cervical vertebrae, and the facial apparatus 

 to the cranial vertebrae, just as the thoracic or costo-sternal apparatus relates to the dorsal 

 vertebra;. 



(;)/;*), that hiatus or gap in costal series (q q </) which interrupts the idea of a con- 

 which is called the cervix, and it is this hiatus tinuous serial costal order ; at the same time 



* In the " Homologies," the author names the 

 maxilke the "inverted arches" of the cranial ver- 

 td>r;u. These inverted arches answer to the haema- 

 pophyses of the author's ideal typical vertebra, and 

 not to the pleurapophysial elements (the ribsj of 

 that ideal form. Now I confess, for my own part, 

 that I do not see clearly why these maxillary arches 

 are referred to the former rather than to the latter 

 elements. There is evidently some mystery about 

 this ideal typical vertebra ligured in the " Homo- 

 I'liA'irs," which I cannot penetrate, and for this 

 reason, viz. that I find the author's " ideal typical 



vertebra," while compared to the osseous segment 

 taken from the bird's thorax, and which he terms 

 the " natural typical vertebra," does not correspond 

 quantitatively. In this ideal form I rind the ribs 

 (pleurapophyses) but as mere rudiments, whilst in 

 the natural form I see that these ribs embrace tho- 

 racic space from the spine nearly to the sternum. 

 Again, in the ideal form the hasmapophyses hang 

 appended to the vertebral centrum; whereas in the 

 natural typical form they articulate with the distal 

 ends of the thoracic ribs. 



