SUPPLEMENTARY OBSERVATIONS ON THE SKULL OF 

 THE FOSSIL PORPOISE ZARHACHIS FLAGELLATOR 

 COPE 



By Remington Kellogg 



Of the Bureau of Biological Survey, United States Department of Agriculture 



During the past ten years a rather large number of vertebrae and 

 other portions of skeletons of cetaceans have been obtained from 

 the Calvert Miocene formation of Maryland. Most of these speci- 

 mens were obtained by digging into the Calvert Cliffs. During 

 severe storms many tons of sandy clay are dislodged from the face 

 of the cliff by the undercutting action of the incoming tide. Many 

 specimens are destroyed in this manner and at the same time others 

 are exposed. Worn vertebrae and fragments of bones are found at 

 frequent intervals on the beach along the Calvert Cliffs after a 

 storm. With the exception of the zygomatic processes and the 

 condyles, the bones of the skull do not withstand being rolled about 

 by the waves and are soon broken up. Wlien remains of pelagic 

 mammals are found undisturbed in the greenish sandy clay, they 

 are usually well preserved. Complete skeletons of these mammals 

 are rarely found, but broken ends of bones and portions of skulls 

 are often found protruding from the face of the cliff. 



Norman H. Boss, to whom we are indebted for most of the speci- 

 mens described in this and the preceding papers,^ has been extremely 

 fortunate in locating and collecting specimens of fossil porpoises. 

 One of the skuUs which he collected during the past year belongs 

 to the Miocene porpoise, ZarJiacMs jiagellator. Although incom- 

 plete, this skull supplies most of the structural details which were 

 missing on the other specimen. The locality at which this skull 

 was obtained is less than 2)4, niiles south of the previous discovery. 



The only certainly known remains of ZarhacMs Jiagellator from 

 the Atlantic coast province of North America belong to four indi- 

 viduals. One of these is the type specimen, a single anterior caudal 

 vertebra; a fairly complete skeleton which was described in 1924 

 represents the second specimen; the third is the cranial portion of 

 a skull hereinafter described and figured; and of the fourth the 

 right periotic alone was collected. 



1 Kellogg, R., A fossil porpoise from the Calvert formation of Maryland. Proc. U. S. Nat. Mus., vol. 

 63, publ. 2482, pp. 1-39, pis. 1-18. March 26, 1924. 



No. 2600.— Proceedings U. S. National Museum, Vol. 67, Art. 28. 



54286— 26 1 1 1 



