190 PROCEEDINGS OF THE NATIONAL MUSEUM. 
VOL, XXXIV. 
the first column are given the actual distances between the points indi- 
cated, as obtained by calipers. In the second column under each 
specimen, opposite each dimension, there is given the percentage 
which this dimension is of the cranial aX1s, whose length stands at the 
head of the first column under each specimen. 
Table of measurements. 
Colpochelys kempi. Caretta caretta. 
No. 29323. No. 13822. No. 29206. 
12} ; ae 
artineasutca Percent- Percent- Percent- 
Dimen- age of Dimen- | age of Dimen- age of 
sions. | eranial sions. | cranial sions cranial 
: axis. axis. axis. 
mm. mm. mm. 
Snout to occipital condyle____-__-._____- | 147 100 | 182 100 175 100 
Width from outside to outside of 
Guadratessus 3 Sis ees AAs ae oe ORT es | 120 82 152 84 150 87 
Snout to end of supraoccipital process_| 207 141 260! 142 239 132 
Snout to extremity of squamosal______| 192 130 240: 121 212 123 
Front of tympanic cavity to extrem- 
MEANY (Oe GCLUATINO RA) tee 62 | 42, 67 37 81 | 47 
Snout to line joining hinder borders | ’ 
of articulation for lower jaw_-____---- | 123 | 84 182 | 100 161 92 
LEON OF OHM be sees 55 37 67 | 37 61 35 
Jalen OG @it Ore oni has = | 41 | 28 64 | 35 55 32 
Depth of cutting-edge of maxilla || 
DelOWAOT DICE es Se a ae Eden 32 22, || 23 13 23 13 
INHUESPROM OWA SOR CO a | 50 34 | 64 35 55 B2 
Height of roof of skull above articu- | 
eaioa, WA WOWPEPE TON ae 103 70: || 135 74 | 135 78 
Height of front of prefrontals above | | 
GHEHINE-GED On mesa... - 62 4? || 58 | 29 55 32 
Least width of combined pterygoids__- 16 11 ON 20 38 22 
Distance of choane behind snout______- 56 38 || 67 37 64 37 
Width of choanal opening behind______- 36 26 3 16 37 21 
Distance between hinder ends of 
Tita sxct |] Soares oe Ss, eee 100 68 | 110 60 118 68 
Length of ramus of lower jaw________- 115 TSp||\ She sce eases 161 92 
From tip of lower jaw to coronoid | 
DEOCES Gein eo Se ad es Ra EE al Non cer er Bh nc Be | ae (eee 102 60 
Meng thot 'SVMPNVSiS es eee eae S| EE Re || Eee eee een 50 29 
Tip of lower jaw to mental foramen__- 65 SRR eet SS es rete ee 58 32 
Thickness of ramus below ecoronoid 
LOCOS Set Utah Gon See ee ee ES 15 Aa a alr ie fee eee 13 7.5 
Attention may be directed to some of the above comparative meas- 
urements. The first of these pertain to the form of the skulls seen in 
profile. The skull of the loggerhead (Plate VII, fig. 1; Plate VIII, 
fig. 1; Plate IX, fig. 2; Plate XI, fig. 3) starts with a greater poste- 
rior elevation and descends rapidly, so that the height at the rear of 
the nasal opening is considerably less than in the bastard-turtle. From 
rear to front, but especially from side to side, the skull of the log- 
gerhead is much more convex than that of the other species. As 
seen from above, the outlines of the upper jaws are straighter in 
the loggerhead than in the bastard-turtle, those of the latter being 
arcuate. In the loggerhead there is a rather abrupt widening of the 
outlines just behind the maxille; in the bastard-turtle the curves are 
continuous from near the snout backward. 
‘It will be observed that the line joining the posterior borders of 
the articulations of the quadrates for the lower jaw is considerably 
