FKOM THE PHOSPHATE BEDS OF SOUTH CAROLINA. 219 



PI. xxxi. It consists of the rostral portion of the skull of a Ziphioid Cetacean, 

 detached in the position of the nasal passages. The end of the beak is lost and a 

 portion of the anterior extremity of the intermaxillaries is broken away, so as to 

 expose half the length or more of the vacant supra-vomerine canal. 



In its present state the specimen measures twenty-one inches in length. All 

 the bones entering into its composition, consisting of maxillaries, intermaxillaries, 

 and vomer, are completely co-ossified, so that it is difficult to assign to the different 

 ones their exact limits. The fossil is almost ivory-like in density and very heavy, 

 as usual with the rostrum of most members of the family. The condition of ossi- 

 fication in its solidity resembles that of the bones of the Walrus and Manatee, and 

 as in these, often misleads persons to consider the state to be due to petrifaction. 



The specimen, like most of the Ashley fossils, is water-worn, and in many 

 places exhibits the boring effect of such mollusks as Gastrochcena, Petricola, etc. 

 It likewise presents a number of attached basal plates of small barnacles, appa- 

 rently of more recent date than the borings of the mollusks. 



In most respects the specimen bears resemblance to a nearly corresponding one 

 from the crag of Antwerp, originally described and figured by Cuvier (Ossemens 

 Fossiles, T. 8, p. 245, PI. 228, fig. 7) with the name of Ziphiiis planirostris, and 

 subsequently referred to another genus by Duvernoy (An. Sc. Nat. 1851, 43), 

 under the name of ChonezipUus. Good figures of the same specimen are given 

 in the Osteographie des Cetaces, by Van Beneden and Gervais, PI. xxvii., fig. 5, 

 with which those of our figures in PI. xxx. and xxxi, reduced to the same scale, 

 may be compared. 



The specimen viewed from above, fig. 2, PI. xxx., presents a long narrow tri- 

 angle with an expanded base corresponding with the interocular or prenasal region. 

 The sides of the triangle in converging towards the end of the beak, present a 

 slight swell outwardly near the middle, but they are not exactly symmetrical. 



The unequal and unsymmetrical prenarial fossae occupying the median portion 

 of the interocular space of the cranium are moderately concave, compared with 

 their condition in Choneziphius planirostris. Shelving downward and forward 

 from their broadest position bordering the nasal orifices, they converge in a funnel- 

 like manner into a pair of grooves extending along the upper part of the beak in 

 the line of conjunction of the maxillaries and the intermaxillaries. The right 

 prenarial fossa is very much larger than the left one, measuring at its widest part 

 three and three-quarter inches, while the latter in a corresponding position is only 

 a little over two inches wide. Externally the prenarial fossae are defined by a 

 curved ridge, which appears to form the outer border of the intermaxillaries. 



/ 



