4 



short distance from it, then converge as they descend, until about 

 two thirds the distance from the summit to the margin, where 

 they are very limited in 

 width, and where the double 

 rows become single. On the 

 margin they again slightly 

 dilate, and are readily trace- 

 able to their termination^ 

 about the mouth, where 

 they are prominent. The 

 anterior ambulacrum is much narrower than the rest. Anus 

 transverse and situated at about one fifth the distance from the 

 posterior margin to the apex. Whole length, one inch and seven 

 eighths ; greatest width one inch and three fourths ; height, one 

 inch. 



Mr. Conrad has redescribed the Pygorhynchus Gouldii, in his 

 paper published in the Journal of the Academy of Sciences, 

 in November last, under the name of NucleoUtes Mortoni. This 

 undoubtedly arose from his specimens being less perfect than 

 those received in Boston. That the fossil under consideration is 

 a Pygorhynchus, was sustained by Prof. Agassiz at the time the 

 original description was given, as may be seen by reference to 

 the Proceedings of this Society. 



Mr. Bouve exhibited specimens of a mineral which w^as 

 formerly considered pure Titanium. It was in the form of 

 minute cubic crystals, and was obtained from the interior of 

 a furnace in Cornwall. The discovery of this mineral was 

 made some time since, but it was only recently that it had 

 been ascertained to be in reality a Cyanuret and Nitruret 

 of Titanium. Its formula is 10 Ti + 1 Cy + 3 N. 



Mr. Wells remarked that the discovery of the true char- 

 acter of this mineral controverted all that had been hitherto 

 known of Nitrogen, which had been considered almost typi- 

 cal of evanescence and instability. It was remarkable, that 

 in the mineral exhibited it had the power of resisting great 

 heat. 



Mr. Wells stated that Mr.'Francis Storer had recently 



