034 SCIENTIFIC RECORD FOR 1884. 



-N'cw American Dhiosaurs.—Frofessov Marsh has contiuned his investi- 

 gations of the American Jurassic Dinosaurs, notices of which have been 

 published in previous numbers of these reports of progress, by the de- 

 scription of anew family of "Sauropoda." A considerable ])ortion of 

 the skeleton of one of the species of the group was exhumed, and it 

 was ascertained that the new family called Diplodocidde was related to 

 the Atlautosanridae and Morosauridre, and distinguished bj' the follow- 

 ing characters : 



Sauropodous Dinosaurs with the ischia having straight shafts directed 

 downw^ard and backward, the ends meeting at median line; a large 

 pituitary fossa, and anterior caudal vertebra3 deeply excavated below. 



Two species of the family have been made known, which have been 

 named DipJodocns longiis and Biplodocns lacustris. The D. longus was 

 intermediate in size between the i)reviously known Sauropods, and is 

 supposed to have been about forty or fifty feet long when alive. The 

 teeth show, according to Professor Marsh, that "it was herbivorous, and 

 the food was ])robably succulent vegetation. The position of the exter- 

 nal nares indicates an aquatic life." The remains of the D. longus were 

 found in Upi)er Jurassic beds near CaQou City, Colo,, and those of the 

 J), lacnstris near Morrison, Colo. All of the American Sauropod Dino- 

 saurians, hitherto obtained, have been found in Upper Jurassic rocks, 

 and no Cretaceous forms of this group are known. The group is sup- 

 posed by Professor Marsh to have the nearest affinities, of all the Dino- 

 saurs, with the Crocodilians. [Am. Journ. Sci. (3), xxvii, pp. 162-168, 

 pi; 3, 4.) 



United metatarsal Bones in a Reptile. — Last year a Dinosaurian reptile 

 was described as Ccraiosaurus nasicornis, whose most interesting fea- 

 ture is to be seen in the metatarsal bones. "There are only three me- 

 tatarsal elements in each foot, the first and fifth having apparently dis- 

 appeared entirely," while the remaining three had become "completely 

 ankylosed," and very much shorter and more robust than in the other 

 members of the group to which it belongs. In fact, the union of the 

 metatarsal elements in the Dinosaur is as perfect as is that in ordinary 

 birds. The position of the foramen, so characteristic of recent birds, 

 is also the same in the Dinosaur. Professor Marsh summarizes that all 

 known adult birds, " with possibly the single exception of Arcliccopteryx, 

 have the tarsal bones firmly united, while all the Diuosauria, except 

 Ceratosaiirus, have these bones separate. The exception in each case 

 brings the two classes near together at this point, and their close affinity 

 has now been clearly demonstrated." (Am. Jour. Se. (3), xxvin, pp. 

 161, 162.) 



The Pteranodous or toothless Pterodactyles. — In 1872 Professor Marsh 

 briefly noticed some remains of reptiles exhumed from middle Cretaceous 



