. Carnegie Institution of Washington publication. TESTUniNID^E. 433 The root ot the mouth (fig. 567) resembles closely that of T. osbormana. The outer ridge of the masticatory surface is strongly developt and dentated. Anteriorly it continues forward on the premaxilla of its side; so that between the right and left ridges there is, in the pre- maxillary region, a deep furrow. The inner ridge of the masticatory surface is broad and rough behind and divided by a deep longitudinal groove. The palate is deeply excavated. On each pterygoid there is a hookt ectopterygoid process. The distance across
. Carnegie Institution of Washington publication. TESTUniNID^E. 433 The root ot the mouth (fig. 567) resembles closely that of T. osbormana. The outer ridge of the masticatory surface is strongly developt and dentated. Anteriorly it continues forward on the premaxilla of its side; so that between the right and left ridges there is, in the pre- maxillary region, a deep furrow. The inner ridge of the masticatory surface is broad and rough behind and divided by a deep longitudinal groove. The palate is deeply excavated. On each pterygoid there is a hookt ectopterygoid process. The distance across the two pterygoids is 30 mm. The lower jaw (figs. 568, 569) is large and heavy. Its length from the symphysis to the angle is 98 mm.; its height at the coronoid process, 32 mm.; at the symphysis, 21 mm. Each ramus has its masticatory surface divided longitudinally by a deep groove. From the outer cutting-edge sharp ridges run down on the outer face of the dentary. The total length of the shell is 922 mm.; the width, 725 mm. The height can not be exactly determined, on account of injuries to the carapace (plate 76). The middle region of this has been broken in, and the fragments considerably disturbed, while the unbroken portions of the costals and to some extent, the peripherals, have been somewhat deprest. It FlGS. 568 and 569.—Tcstudo impensa. Skull and lower jaw of type. X^. 568. Skull, right side. 569. Lower jaw, seen from above. The s7i however, improbable that the shell ever had as great height as that of T. osbormana. width of the carapace is 78 per cent, of the length; whereas, in T. osbormana the width per cent. The peripherals have practically the same form as in the last-mentioned species, but those of the bridge regions do not appear to have had relatively as great height. Neither do the peripherals of the posterior region descend so steeply as in T. osbormana. In the latter the pygal and the adjoining peripherals slope forward from the perpendicular on
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