62 Eobert E. Coker. 



Such crude direct effects of pressure are not to be confused with the 

 possible indirect adaptive results suggested above (p. 49). 



Less than 12 marginals Avere observed only in malformed speci- 

 mens. In No. 35 (Fig. 66), with marginals 8-10, the right marginal 

 series shows less reduction than any other series of the carapace. 

 In No. 93 (Fig. 89) the marginals are 12-10. 



Supramaf'ginals. 



Small scutes, just above the margin and at the meeting-point of 

 three scutes, are noted only in No. 88 of Table VII D (Fig. 85), 

 and in several embryos of Table VII, A (Nos. 43, 47, 48, 50, 51, 

 53 and 55, Figs. 73 and 74). The costals do not seem quite to meet 

 the marginals in early stages, and if the presence of scutes between 

 costals and marginals be attributed hypothetically to arrest of devel- 

 opment, these observations may lend some support to Newmnim's 

 hypothesis as to the number of primary series of scutes in the cara- 

 pace. But would not such an assumption as to the significance of 

 supramarginals place them in a distinct class from other super- 

 numerary scutes for which arrest of development is not to be hypothe- 

 cated ? 



Nuchal. 



As was the case in Malaclemmys^ so here the nuchal is frequently 

 found in paired condition (eleven instances. Fig. 103, etc.), or 

 marked by a median furrow, which may be quite distinct (three 

 instances) or very faint (four instances). In one case an anterior 

 seam was continued posteriorly by a furrow (No. 93, Fig. 89).* 

 The furrow is incomplete in No. 78, Fig. 82, and the seam incom- 

 plete in 88, Fig. 85. The division is usually symmetrical but not 

 always so. 



Costals. 



Each cosital series consists of five scutes, the most anterior being 

 very small, and having no analogous element in Malaclemmys. It 

 may be noted that, when there are twelve marginals, the first two 

 costals are in contact with the first five marginals. In Malaclemmys, 

 which has, typically, twelve marginals, the first costal is in contact 



*Also No. 102, Fig. 94. 



