426 MESOZOIC TIME — REPTILIAN AGE. 



The number of species of birds named by Hitchcock from the 

 footprints of the Connecticut valley is thirty-one. 



Fossil bones have been obtained from these beds at Windsor, Ct. 

 They are hollow, and may have belonged to birds ; but Dr. Wyman 

 states that it is also possible that they were the bones of Flying 

 Reptiles. 



The only Mammal thus far made known was discovered by 

 Professor Emmons in North Carolina. The specimen is a jaw- 

 bone (fig. 650), and it belonged, according to Professor Owen, to 

 an Insectivorous (Insect-eating) Marsupial near the modern genus 

 Myrmecobius of Australia. The species has been named by its dis- 

 coverer Dromatherium sylvestre. 



It is altogether probable that Mammals of similar kind were 

 associated with the Birds and Reptiles in the Connecticut valley. 

 To give some idea of the general form of the earliest of Mam- 

 mals, a drawing of the Myrmecobius is given in fig. 663 B. The 

 genus is confined to Australia. 



Characteristic /Species. 



1. Mollusks. — Conchi/ers. — Myacites Pennsylvanicus Conrad, from the Black 

 slate of Phoenixville, Pa. Two other species, referred by Wheatley with a query 

 to Pholadomya and Unio or Potamomya, occur at the same locality. — An 

 imperfect shell from near Mount Tom, Mass., is referred by E. Hitchcock, Jr., 

 to the Rudistes. — The Posidonise, formerly supposed to be Molluscan, are now 

 regarded as Crustaceans of the genus Estheria. 



2. Articulates. — (a.) Crustaceans. — Ostracoids : Fig. 631, Estheria ovata 

 Lea (Posidonia minuta), from Richmond, Va., and Phoenixville, Pa., resembles 

 the P. minuta- of the European Trias ; fig. 632, E. oralis Emmons, from North 

 Carolina, and fig. 632 A, E. parva Lea, Phoenixville, Pa., are both E. ovata ac- 



Figs. 631-632 B. g2A 



32 



Fig. 631, 632, 632 A, Estheria ovata; 632 B, Palephemera mediseva (X %). 



cording to T. R. Jones. Two species of Cypris, one smooth and the other granu- 

 late, occur at Phoenixville and Gwynned, Pa. Figs. 636, 637 represent tracks 

 referred by Hitchcock to Macrouran Crustaceans. 



(6.) Insects. — Fig. 632 B, exuvia of a Neuropterous larve, related to Ephemera, 

 according to J. L. Le Conte. The appendages along the sides are probably 



