NATURAL SCIENCES OF nilLADELPHIA. 9t 



February 4. 

 Mr. Vaux, Yice-Presiclent, in the chair. 

 Eighteen members present. 

 The following papers were presented for publication : 



" On the Lingual Dentition of Certain Terrestrial Pulraonata 

 from the United States, with remarks on their systematic value." 

 By Thos. Bland and Wm. G. Binney. 



" Catalogue of the recent species of the Class Brachiopocla." 

 By W. H. Dall, TJ. S. C. S. 



" Descriptions of Mexican Ichneumonidee." By E. T. Cresson. 



Notice of Bemaivf! of Fifthes in the IhHdgey^ Tertiary Forma- 

 tion of Wyoming. Prof. Leidy remarked that among the multi- 

 tude of fossils which had been collected from the tertiary clays 

 and sandstones of the Bridger Group of Wyoming, there were com- 

 paratively few pertaining to fishes. Nevertheless the remains of 

 these are not unfrequent, but they are not so com})lete as one 

 might have expected from the nature of the beds containing them. 

 They usuallj" occur as isolated bones, scales and teeth, and mostly 

 Indicate fishes related Avith our living Gars (^LejDidosteus), and 

 Mud Fish (Amia). 



Prof. Marsh has already noticed several species of these fishes 

 in the Proceedings of this Academy, 18*71, p. 105, from the Bridger 

 beds. Two of the species belong "to the genus Amia, about the 

 size of the modern A. calua.,^' the others indicate two species of 

 Lepidosteus, "both having smooth scales and about the same size 

 as the modern gar-pike." 



The specimens submitted to our examinations from time to time 

 consist of isolated vertebral centra, ganoid scales, fragments of 

 jaws with teeth, and portions of spines. Many of these appear to 

 indicate the following extinct species previously undescribed : 



Lepidosteus atrox. Founded on remains, obtained in Prof. 

 Hayden's expedition of 18T0, at the junction of the Big Sandy and 

 Green Rivers. They indicate a fish larger than the Alligator Gar 

 of the Mississii)pi. A vertebral centrum from near the middle of 

 the dorsal series is S^ lines long. It is flat beneath and ornate 

 with longitudinal and somewhat reticulate wrinkles. The para- 

 poplyscs are proportionately' narrower than in the Alligator Gar. 

 The accompanying scales have their ganoid surface perfectly 

 smooth, flat, and without markings, and they arc thicker than in 

 the Alligator Gar. 



