On the Osteology of Nyctosaurus. 155 



though the author expressly stated that the "coracoid and scapula were 

 firmly anchylosed" a character seen in the present specimen of Nycto- 

 saurus, I feel pretty confident that the type of P. nanus does not have the 

 articular extremity of the scapula so characteristic of Nyctosaurus. The 

 description of P. comptus might apply, except in size, to either Nycto- 

 saurus or Pteranodon. I refer the species to the former genus because of 

 its small size, but its synonymy is not assured. That a better basis for an 

 opinion may be given the reader, I here reproduce all that Marsh has 

 written upon Nyctosaurus and the two small species which he referred to 

 Pteranodon. 



" One of the smallest American species yet found is represented in the 

 Yale Museum by several bones of the wing, a number of vertebrae and 

 the nearly complete pelvis. The wing bones preserved are elongated 

 and very slender. The pelvis is unusually small, and there are five 

 vertebrae in the sacrum. The last of the series indicates that the tail was 



short. The following are the principal dimensions of this specimen: 



mm. 



Length of ulna 187 



Length of metacarpal of wing finger — 300 



Antero-posterior diameter of outer condyle at distal end 15 



Tranverse diameter of shaft, above condyles . 13 



Length of first phalanx of wing finger . 347 



Extent of five vertebrae of sacrum 57 



"This species, which may be called Pteranodon gracilis, was about two- 

 thirds the size of P. velox Marsh. It probably measured about ten feet 

 between the tips of the expanded wings."* 



" Pteranodon comptus, sp. nov. The smallest Pterodactyle known from 

 American strata is indicated by portions of three skeletons in the Yale 

 Museum. Among these remains are two distal ends of the characteristic 

 metacarpal of the wing finger, other portions of the wing bones, and two 

 sacral vertebrae. The large metacarpal is very slender and elongated, 

 and its outer distal condyle has its superior margin elevated above the 

 shaft, and terminated proximally in a point. The ulna is comparatively 

 large, and the proximal carpal has an oval air cavity on its radial side. 

 The sacral vertebrae have their centra short, and medially constricted. 



" The principal measurements of the remains of thisspecies are as follows: 



mm. 



Greatest diameter of ulna at distal end 15 



Transverse diameter of proximal carpal 17 



Antero-posterior diameter of outer distal condyle of wing metacarpal 12 8 



Longitudinal extent of condyle 11.6 



Transverse diameter of shaft above condyle -- 11.5 



Length of medial sacral vertebra 9 



Transverse diameter of centrum 8.4 



♦Marsh, Amer. Journ. Sci. June, 1876, p. 508. 



