1851.] 173 



and quadrilateral, and pass, one upon each side, from the antero-external angle 

 of the hyo-sternal bone obliquely upwards ami inwards to a depression about the 

 middle of the outer margin of the first costal plate. The posterior column? of 

 support have nearly the same form as the anterior, and pass from the postero- 

 external angle of the hypo-sternal bone upwards, backwards and a little inwards 

 to a depression formed at the junction of the fifth and sixth costal plates. Dr. 

 L. gave to this fossil the generic and specific name of Stylemys* nebrascensis. 



^pril 2'2d. 

 Vice President Bridges in the Chair. 



A letter was read from Mr. John Hooper, Secretary of the Brooklyn 

 Institute, dated New York, Feb. 17th, 1851 , accompanying a beautiful 

 collection of native Algfc, (42 species,) presented by him to the Aca- 

 demy, and offering to contribute further if desirable. 



Mr. Cassin read a paper intended for publication in the Proceedings, 

 entitled "Notes of an Examination of the Birds composing the family 

 Caprimulgidre in the collection of the Acad. Nat. Sciences ;" which 

 was referred to Dr. Wilson, Dr. Watson and Dr. Ruschenberger. 



Dr. Leidy called the attention of the members to two fossil Tortoises from 

 Nebraska Territory, received through Professor Baird. 



One of them consists of a great portion of the carapace and sternum broken 

 into two fragments. It belongs to the genus Testudo. Its length has been 

 about 2 feet, the breadth is 20 inches, and the height 9 inches. The bones are 

 thick and strong. The species Dr. L named Testudo lata. 



The second specimen consists of four-iifths of the sternum and about one-third 

 of the carapax. In its perfect state it has been about 9i inches in length, 7i in 

 breadth, and about 5h hish. The carapace is very convex. The costal plates 

 are alternately narrow and broad at their outer extremity, and have been united 

 to the marginal plates by cartilage. The latter rise at first a little convex from 

 the sternum, but are afterwards vertical. The species Dr. L. named Emys 

 hemispherica. 



Mr. Isaac Lea, referring to his late communication to the Academy 

 on the subject of fossil bones in the collection from the new red sand- 

 stone, stated that since then he had received the Proceedings of the 

 Boston Natural History Society, which contained a paper by Mr. 

 Welles, read in December last, noticing the fact that fossil bones of 

 laru^e vertebrate animals had been found in two instances in the red 

 sandstone of Connecticut valley. Mr. Lea said that this was the first 

 notice he had met with of the discovery of bones of this character in 

 this forination. 



Dr. Morton offered some remarks on the infrequency of mixed off- 

 spring between the European and Australian races. 



The singular paucity of half-caste or mulatto children in New Holland, has 

 been remarked ever since that country was first colonized by Europeans. Of 



