[PLATE 23]

1. Left leg and pelvis of Ichthycanthus platypus Cope, from the Coal Measures of Ohio. × 1.7. Original the property of the Department of Geology of Columbia University. c=centrale; F=fibula; fi=fibulare; Fe=femur; i=intermedium; Il=ilium; T=tibia; t, 1-5=distal tarsalia; ti=tibiale; V=caudal vertebræ; I-V=digits.

2. Ventral scutellæ of Ctenerpeton alveolatum Cope, from the Coal Measures of Ohio. × 3.5. Original in U. S. National Museum.

The fore limb is represented by the upper portions of the ulna and radius and 2 digits of the right hand. The digits are long and slender and seem to represent digits I and II, since they show evidences of 3 and 4 phalanges respectively. The portions of the forearm preserved are too meager for description.

The vertebræ have already been characterized as of the type first described in Urocordylus. The neural fans are not much, if any, wider than the hæmal fans. They are both situated on an elongate spine with a slender base. The edges of the two fans are pectinated and the dorsal spine is distinguished by the presence of a longitudinal groove in the center of the spine. The length of the tail may have been considerable, judging from the character of the vertebræ preserved

Measurements.

mm.
Length of specimen150
Width of belly, maximum 28
Length of lateral chevron plate 7
Width of lateral chevron plate 1.75
Length from tip of lateral chevron to median angle 10
Length of a caudal vertebra 10
Width of the same vertebra with spines 20
Height of neural spine 8
Height of hæmal spine 8
Width at distal end of hæmal spine
Width at distal end of neural spine 3.5
Length of foot, as preserved 12

Genus LEPTOPHRACTUS Cope, 1873.

Cope, Proc. Phila. Acad. Nat. Sci., p. 340, 1873.