2 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 63. 



of Natural Sciences, Philadelphia; to Dr. W. D. Matthew, of the 

 American Museum of Natural History, New York ; and to Gerrit S. 

 Miller, jr., of the Division of Mammals, United States National 

 Museum. Dr. John C. Merriam, president of the Carnegie Institu- 

 tion of Washington, has kept in touch with this work as it progressed 

 and I am indebted to him for assistance. 



THE GENUS ZARHACHIS COPE. 



Type. — Zarhachis flagellator Cope, E. D., Proc. Acad. Nat. Sci., 

 Philadelphia, vol. 20, pp. 186, 189, 1868; vol. 21, pp. 9-10, 1869. 



Type locality. — Miocene marl of Charles County, Maryland. Cal- 

 vert formation. Upper Miocene. 



Type specimen. — An anterior caudal vertebra. Cat. No. 11231, 

 Academy of Natural Sciences of Philadelphia. 



Cope proposed Zarhachis flagellator for two lumbar and two 

 caudal vertebrae which were assumed to represent three different 

 individuals. Three of the vertebrae mentioned in 1868 were sub- 

 sequently withdrawn by Cope and referred to other species. In 1868, 

 Cope referred the genus Zarhachis to the family Delphinidae, but 

 in a later article^ he allocated the genus with the Platanistidae. 



The original description consists of the following : 



ZARHACHIS Cope. 



This genus is established on vertebrae wliich bear a general resemblance to 

 those of P7-isco(lelphinus, but differ in the essential point of having flat and 

 broad diapophyses of the caudals. It is therefore intermediate betvi^een that 

 genus and Delphinapterus. The posterior of the caudals in our museum 

 exhibits a narrowing of the diapophyses, as certain of the lumbars do in 

 Priscodelphintis. 



ZARHACHIS FLAGELLATOR Cope. 



This species is represented by only two lumbar and two caudal vertebrae, 

 which belonged to at least three different individuals, none of them adult. 

 Neither is any one entirely perfect, but they indicate a very distinct species, 

 by clear characteristics. All of these vertebrae are of greater length as 

 compared to the diameter than in any other cetacean known by me except 

 the great Basilosaurus. The lumbars, when compared with those of T. lacer- 

 tosus, differ in their broadly obtuse median line, which offers distinct trace 

 of the two keels. An anterior caudal either exhibits unusually broad dia- 

 pophyses, which are directed downwards, or else is a lumbar with two keels, 

 and a median groove below, which is not seen in any other species. The 

 caudals exceed in length those of any other species. One of these, from a 

 large individual, resembles that of P. atropius in the narrow basis of the 

 diapophysis which is probably narrow, and not perforate. The length of the 

 vertebrae Is nearly double the vertical depth of the articular faces. The 

 diapophysis is nearly median ; the basis of each neurapophysis is one-half 

 the length of the centrum, and median. 



1 Cope, E. D., The Cetacea. American Naturalist, vol, 24, p. 615. July 31, 1890. 



