1869.] 99 [Coues. 



ticularly to the optic nerves. The other bone is merely a little curved 

 splint bridging across the lower part of the frontal ring from side to 

 side, and partially making up for the defective condition of the latter. 

 I do not know to what, if any, bone this bit is to be referred, and 

 prefer not to hazard a conjecture. The haemal arch of this third 

 vertebra is not noticeably deformed, though rather unusually short- 

 ened, thickened and bent upward at the end. Each moiety is dis- 

 tinct, and has three projecting teeth; the future molars and premolars 

 still lie buried in the jaw. 



As we trace haemal arches of the mammalian cranium, in the light 

 of Owen's conception of them, we find that they are regularly grad- 

 uated from behind forward, as to the kind and degree of their 

 connection with the rest of the skull. That of the occipital segment 

 is removed to the thorax, and only connected by muscular tissue. 

 That of the parietal is suspended in the neck by ligamentous bands 

 that may acquire bone-earth along a part or the whole of their course. 

 That of the frontal is in contact with the rest of the skull, and mov- 

 ably articulated. That of the nasal is suturally united, in firm 

 apposition, not only by extensive and intricate pleurapophysial con- 

 nections, but also by that junction of the haemapophyses and haemal 

 spines with neural elements that is necessary to close up the neural 

 axis in front, and gives the more or less conical configuration to this 

 extremity of the vertebral series. The obscurity that hangs over the 

 " nasal vertebra," and the consequent difficulty of actually distinguish- 

 ing neural and haemal " arches," or of recognizing a "vertebra" at 

 all, is commonly held — with what show of reason it is not my pur- 

 pose to inquire — to result in great measure from this extreme modi- 

 fication in the face of a special emergency that does not elsewhere 

 occur. Be this as it may, we have in the present instance of this 

 malformed skull, a nasal vertebra, the neural and haemal arches of 

 which are distinct and separated from each other, and which displays 

 vertebral characters at least as plainly as either of the other cranial 

 segments do. It consists of a neural spine, surrounding and enclos- 

 ing the prolongation of the neural axis, uplifted from its centrum, 

 wanting neur apophyses, and with no osseous sense-capsule; and of a 

 detached haemal arch, represented by pleurapophyses, haemapophyses, 

 (and haemal spine ?) joined to its centrum, by the latter attached to 

 the rest of the skull, with which it is only further joined by its 

 " appendages." 



The single nasal bone, apparently developed from one centre, is 



