ART. 16, TWO SQUALODONTS FROM MARYLAND—KELLOGG. 67 
of bone whose posterior face is grooved by the external auditory 
meatus and whose anterior face is continuous with the glenoid fossa. 
The process is rather broad and terminates in a rounded tip. 
When viewed from the ventral side (pl. 20, fig. 1a) the glenoid sur- 
face is seen to be strongly concave antero-posteriorly and rather nar- 
row from side to side. On the internal and posterior margin of the 
glenoid fossa there is a shallow cavity measuring approximately 25 
by 48 mm., the function of which is uncertain. A third low knoblike 
process fills in the space between the groove for the external auditory 
meatus and the exoccipital. 
MEASUREMENTS FOR THE SQUAMOSAL., 
Distance from tip of zygomatic process to tip of postglenoid process.......... 141 
Distance from tip of zygomatic process to posterior margin of exoccipital--... 184 
Greatest bread ii of clenoid(suriace: setae oa... Sees. Ses Ines 53 
Greatest wenethianclenoidysuTiaces 2. ss.j5 igen ds a Aa dysin aceon nis «STR 100+ 
The exoccipital varies greatly in thickness, being massive at the 
ventro-external border and thin superiorly. The superior margin 
(pl. 20, fig. 1b) is deflected backward and presumably represents the 
external projection of the lambdoidal crest which follows the curva- 
ture of the temporal fossa. Externally the exoccipital is suturally 
united with the squamosal, the remainder is free, and forms the pos- 
terior wall of the periotic recess. A large paroccipital process is 
formed by the ventral expansion of that portion of the exoccipital 
adjacent to the knoblike process of the squamosal. 
FRAGMENT OF A RIGHT MAXILLA. 
Among these fragments is a portion of a right maxilla (pl. 18, fig. 2). 
In its general form the maxilla was undoubtedly much like the cor- 
responding element in the skull of Squalodon calvertensis. Two 
double-rooted alveolae are present, and these are too small to bear 
teeth as large as those of the large squalodont discussed previously. 
The fragments collected by Palmer do not bear any collector’s num- 
bers, and it is possible that this fragment of the maxilla was at some 
time accidentally placed in the tray containing the larger specimen. 
EXPLANATION OF PLATES. 
Squalodon calvertensis, new species. No. 10484, Division of Vertebrate Paleontology, 
U. 8. National Museum. Calvert formation, western shore of Chesapeake Bay, 
about 2 miles south of Chesapeake Beach, Calvert County, Maryland. Collected 
by Norman Boss July 8, 1921. 
PuateE l. 
Type skull of Squalodon calvertensis, new species. About two-fifths natural size. 
Dorsal view. The superior margin of the mesethmoid is imperfectly preserved and 
has been restored in the figure, 
The same abbreviations are used on Plates 1 to 4 for the following parts: Al., 
alisphenoid; Bo. pl., descending free plate of basioccipital; Bs., basisphenoid; C., 
