1895.] 1*^1 [Cope. 



Measurements. M, 



Length of parapopliysis of second cervical from centrum. . . ..135 



Greatest length of humerus 



Anteroposterior diameter of head 130 



Anteroposterior diameter of shaft at middle 115 



Diameters of distal end | transverse (somewhat crushed). . . .075 

 ( anteroposterior 170 



For the opportunity of describing this specimen I am indebted to the 

 Rev. John T. Goucher, President of the Woman's College of Baltimore, 

 who kindly placed the specimen at my disposal. I am also indebted to 

 Prof. Arthur Bibbins, of the same institution, who first drew my atten- 

 tion to it. The specimen was presented to the Woman's College by Dr. 

 Richard Eppes, of City Point, Va., wlio obtained it from the Yorktown 

 bed at Tarbay, not far from that place. Dr. Eppes discovered in the year 

 1854 the specimen whicli became the type of the S. priscus of Leidy, and 

 it is through his hospitality that I have been enabled to visit recently the 

 locality, seven miles below City Point on the James river, where the 

 skull of the C. crassangulum was found. 



BAL.ENOPTERA SURSIPLANA, Sp. nOV. 



Five species of Balsenidse from the Yorktown bed are known from otic 

 bullae. These are Balcena mystketoides Emmons, Mesoteras kerrianus 

 Cope, Getotherium cephalus Cope, C. megalophysum Cope, and G. crass- 

 angulum Cope. The present species will be the sixtli. It is established 

 on a bulla from the Yorktown formation of Maryland, and is in excellent 

 preservation, the middle portion of the inferior thin wall being absent. 



It is not necessary to compare this species with any of those of the 

 genus Cetotheriura. On comparison with the Baleenopteroe described by 

 Van Beneden, it is to be observed that they all difier from the present 

 form in the convexity of superior face, where the dense layer or lip has a 

 different chord or face from that of the space which separates it from the 

 internal longitudinal marginal angle. In the B. sursiplana there is but 

 one superior plane from the eustachian orifice to the internal edge, which 

 is absolutely flat. In all these species also the dense layer of the lip is 

 reflected on the superior edge of the external thin wall at its anterior end. 

 In the present species this layer is reflected in a very narrow strip under- 

 neath the free border, which overhangs it. In all these species also the 

 anterior extremity, as viewed from above or below, is angulate, the angle 

 marking tlie end of the inner border of the dense layer or lip. In B. 

 sursiplana the anterior extremity, viewed in the same way, is truncate. 

 The species which appears to approach nearest is the B. definita Owen, 

 which is figured by Lydekker.* This otolite appears to be flatter above 

 than the species described by Van Beneden, although the figure is not 

 clear in this respect. It has the oblique upwards and backwards looking 

 face at the posterior extremity, whicli is a conspicuous feature of the B. 



* Quar. Jowrn. Geolog. Society, 1887, PI. ii, Fig. 3, p. 11. 



