44 



THE GEOLOGIST. 



genera. The scales of Glyptolepis are far more numerous — appa- 

 rently as four to one — and are set more closely together and with a 

 deeper imbrication than those of Holoptychius. There is a consider- 

 able variety, although nothing of the kind can exceed the beauty of 

 the sculpture of the scales as taken from different parts of the body. 

 The scale of Holoptychius {all wrinkle) may be represented by the ac- 

 companying figure, PI. III., fig. 4. It is divided into two portions: the 

 anterior portion, which is smooth, and is covered by the imbrication : 

 and the posterior portion, often deeply sculptured with anastomosing 

 ridges. The scale of Glyptolepis (carved scale) may be represented by 

 the accompanying figure, PL III., fig. 5, although in this genus there is 

 a greater variety in the sculpturing. It is divided, also, into two por- 

 tions : the anterior portion, which is covered with a beautiful ar- 

 rangement of small eminences, radiating in concentric circles from 

 the middle of the scale, and becoming very minute as they approach 

 the margin ; and the posterior portion, which is covered with ridges, 

 leaving sometimes a smooth edge on the hinder margin. 



The cranial bones of both genera are also sculptured, but with a 

 difference. Those of Holoptychius are covered with a confluent 

 tuberculation, whilst those of Glyptolepis present waving longitu- 

 dinal ridges. 



On the Holoptychius one of the dorsal fins is alone shown, pre- 

 senting, however, stouter rays than the pendulous corresponding fin 

 of the Glyptolepis. Unfortunately, no comparison can be instituted 

 from this specimen respecting the caudal fins of the genera. 



The dentition of the Holoptychius is not seen, but Glyptolepis 

 displays several large teeth intercalated amongst a series of small 

 ones. The medial line along the flank is far more deep and marked in 

 Glyptolepis than in Holoptychius. 



Prom the description given by Mr. Powrie of the St. Andrews 

 specimen, we are led to suppose that two species of Glyptolepis occur 

 at Dura Den — the other much larger than the species we have at- 

 tempted to describe as above. But one thing is certain, the genus 

 is to be found there. The determining of this matter may cast no 

 new light on the position of the sandstone of Dura Den, but at least 

 it will prevent confusion in the description of its palaeontology. 



NOTE ON STONE "CELTS" EEOM CHIRIQUI. 

 By Charles Carter Blake, Esq. 



{Head before the Ethnological Society, March 18, 1862.) 



Five stone " celts " have been submitted to me, from the collections 

 of antiquarian objects from Chiriqm formed by my friends William 

 Bollaert, Esq., F.K.G.S., Oorr. Mem. Univ. Chile,*etc., and W. Du- 

 pree, M.D 9 , P.B.G.S., of Panama. 



No information has been given to me respecting the locality, 



