ON THE OSTEOLOGY OF NYCTOSAURUS (NYCTODAC- 
TYLUS), WITH NOTES ON AMERICAN PTEROSAURS. 
BY SAMUEL W. WILLISTON. 
In previous papers* I have given a summary of the principal characters 
of the genus Wycfosaurus,t with more or less complete descriptions of cer- 
tain parts of the skeleton. In the present paper I give a more detailed 
description of the skeleton, based upon the unusually well-preserved and 
nearly complete specimen collected by Mr. H. T. Martin, together with 
some remarks upon the relationships and habits of the American 
pterosaurs, and the description of a new genus and species from the 
Lower Cretaceous of Kansas. 
The specimen herewith described is of unusual importance, as throw- 
ing much light upon the structure, not only of the American pterodactyls, 
but also upon certain characters of the European ones. It is, I believe, 
for purposes of study the most complete specimen of this order of reptiles 
now known, comprising as it does nearly every bone in the skeleton, for 
the most part associated in their natural relations. The specimen now 
forms a part of the collections of the Field Columbian Museum. 
SKULL. 
A full description, with illustrations, of the skull has been given in the 
Journal of Geology, vol. x, 1902, p. 520. I give herewith illustrations 
of the mandible, not there figured. A careful measurement of the 
sides of this bone a little in front of the posterior end of the symphysis, 
where they are the broadest, obtained by measuring each fractured portion, 
gives a width for each side of twenty-four millimeters. The correspond- 
ing width of the palate is twenty-eight millimeters. This would give, as 
the greatest depth of the mandible, near the end of the symphysis, 
about twenty millimeters. 
* Kansas University Quarterly, vol. i, p. 5, 1892. 
American Journal of Anatomy, vol. I, p. 297, 1902. 
Journal of Geology, vol. x, p. 520, 1902. 
Text Book of Paleontology, Zitte] (Eastman), vol. ii, p. 255, f. 361. 
+ This genus has generally been known as Wyectodactylus. (See synonymy beyond.) Marsh 
changed the name because of the supposed preoccupation of the name Vyctosaurus. In this he 
was not justified. The name has never been used otherwise for a genus of animals. Doubtless he 
thought the term conflicted with Nyctisauria, used for a group of sauria. It does not, however, 
according to the accepted canons of nomenclature, and the original name should not be displaced, 
FIELD Cot. Mus., GEOL. SER., Vol. II, No. 3. 
