530 A. Smith Woodimrd — A Devonian Ccelacanth Fish. 



An explanatory outline sketch of this fossil, of the natural size, 

 is given in the accompanying figure. It is based upon Von Koenen's 

 heautiful drawing. In the left upper corner are the two opercula 

 (op.), slightly overlapping and exposing their outer ornamented 



Coslaccmthus Kayseri (Von Koenen) ; outline of associated head-bones, etc. Upper 

 Devonian: Mlillenborn, Gerolstein. For explanation of lettering see text. 



face. They taper rapidly in their lower half, and their maximum 

 width is about three-quarters the measure of their maximum depth. 

 The ornamental ridges are frequently interrupted, almost all directed 

 horizontally, and somewhat coarser behind than in front. Below 

 these plates are the two clavicles {cl.), rightly identified by Von 

 Koenen. Their lower end is obscured, but the upper portion has 

 the typical Ccelacanth form and is marked by a few transverse 

 ridges. Another characteristic fragment of bone {x.) lies to the 

 right of the expanded lower end of the clavicles. This is the 

 hinder part of the supposed copula of the branchial arches. The 

 two gular plates {gu.) are distinct, each slightly more than four 

 times as long as broad, and ornamented with fine concentric ridges, 

 which are not subdivided into tubercles. These plates seem to be 

 gently rounded at either end, not tapering in front more than 

 behind. Eemains of the mandible {d.) occur on each side of the 

 gular plates, and the characteristic articulo-angular bone (ar.) of the 

 left side is displaced so as to show its form and proportions. It is 

 ornamented with fine ridges which are mainly directed longitudinally. 

 Upwards and forwards the two pterygo-quadrate elements {ptq.) 

 seem to be crushed together ; but these and other fragments are too 

 imperfect for description. 



Sufficient characteristic bones are thus preserved to indicate that 

 the fossil in question represents a typical Ccelacanth head. The 



