1871.] 45 [Cope. 
‘vertebrals are short coffin-shaped, concave or emarginate in front; a stout 
laminar neural spine supports the vertebra below. 
The sculpture of all the bones is a delicate impressed punctation, the 
‘impressions forming lines or delicate grooves in some places. These run 
-obliquely across some of the costals and marginals, and sublongitudinally 
on the posterior lobe of the plastron. The corneous scuta have left dis- 
tinct impressions. The marginals extended on to the costal bones at the 
place of the fiee marginal bones. The vertebrals were a little longer than 
wide, witb bracket shaped lateral sutures, and openly emarginate below. 
The intergular plate was pentagonal, with straight sides, and broader 
than long. The gulars are short and not prolonged very far on the 
outer margin of the plastron. The pectorals are narrowed laterally, and 
present a convex median outline on the mesosternum. The abdomino- 
femoral suture crosses a little behind the middle of the hyposternal bone. 
The median longitudinal suture winds from side to side on the posterior 
lobe in the most erratic fashion, abnormally no doubt, and the suture for 
the anals is anterior, convex in front, sigmoid at the sides. 
Measurements. M. 
Length of plastron (restored)...............-. ancieemies es 0.457 
“ from front to postabdominal suture............... .B4 
es BS to (right) hyposternal..... eevee ete 195 
ve a to hyosternal.......... ee -104 
a ss to mesosternal......... 6. .e cece ee eee 038 
Width at mesosternal.... 6.0... 6c cece eee cette eee eee 194 
«of Mes) coipaalerae Sah aiapala i aubahast Aedes ee. ete tanta 095 
*¢ at postabdominal suture........... ds eeaidecss nai e areas 22 
Thickness of mesosternal behind...................505.. .0116 
a of hyposternal medially...........+.. see e ee eee 0158 
Width of average costal at vert. scute suture............- 055 
Thickness of same.... 2.6... cece eee eee eee teen 011 
Total length adjacent vertebral. ........... ....--.5---55 066 
Greatest WIdthicsc cos cccuieeetesssedesesee oles suwegheaien 036 
Width do. at end.... 2.0... cece cece eee ence eee 022 
Length of first free marginal from bridge.... ...-......-- 0655 
Width Of dO. cessed verre ngisws eseaieneeiass Bec deeb tess .10 
Thickness proximally.........66:6 eee eee e eee eee eee 0175 
me of a free marginal proximally..........--.-+++ 01 
Width es Be heh EEL Rae gene eceaie 075 
Length i fe abeesailnns eeneaeaaad tals 0548 
The type specimen of this species is about twice the size of that of Z. 
striatula. It also differs in some respects which might be attributed to 
age, as the greater recurvature of the marginal bones and the greater ex- 
tent or prolongation of the thickening on the inside of the marginals next 
the bridge. But there are others which appear to be specific. Thus 
there is very little evidence of cross-union of sternal elements in the Z. 
strtatula, and the sculpture is twice as coarse and so much more marked. 
