. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 392 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY or fifth. The most common order from longest to shortest is 3-4-2-5-6-7-8. The eighth neural varies greatly in shape, but is no doubt to be considered basically hexagonal like the others (Figure 5 ). The first vertebral scute, as mentioned above, is inconstant in proportions, with that of the type being the narrowest (length 139 per cent of width). The range of the same ratio in other specimens is from 84 to 127 per cent. The second vertebral scute appears to be always more
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 392 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY or fifth. The most common order from longest to shortest is 3-4-2-5-6-7-8. The eighth neural varies greatly in shape, but is no doubt to be considered basically hexagonal like the others (Figure 5 ). The first vertebral scute, as mentioned above, is inconstant in proportions, with that of the type being the narrowest (length 139 per cent of width). The range of the same ratio in other specimens is from 84 to 127 per cent. The second vertebral scute appears to be always more or less urn-shaped, with its lateral borders distinctly curved. In some cases, the length on the mid-line and greatest width are about equal, but mostly the scute is up to 25 per cent wider than long. The third vertebral is also urn-shaped, but its lateral margins, while having the shape of brackets, are straighter than those of the scute in front of it. It oftener has the length and width about equal; the mean length/width ratio is Two of the specimens studied have extra components. The supernumerary costal scutes of the hollandi type are discussed above. A fragment from the Wampus Cat quarry shows the suture of an extra posterior peripheral bone which occupies por- tions of the pygal and its contiguous peripheral on the left side (Figure 6).. Fig. 6. Echmatemys septaria callopyge. Diagram of pygal and posterior peripherals, showing suture for supernumerary peripheral (MCZ 3145). Growth Pattern Fortunately, several immature specimens have been collected, and while they are in most cases rather incomplete, the growth pattern is indicated in three respects. Taking the type as an example of a full-grown mature individual, the smallest shell is about Y5 the adult size. The Uinta fossils have been com- pared with a series of Chrysemys picta marginata from Cuyahoga Co., Ohio, in the Cleveland Museum collection, and a comparison is shown in Table II. Naturally, the vertebral s
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