106 



G. R. Wieland — On Marine Turtles. 



neuro-pleural series, or they have been so badly crushed as to 

 render the general form and structure more or less doubtful, 

 as in the case of the Carnegie Museum specimen that yielded 

 such clear testimony to all the characters of limb organization; 

 and even in the present instance the evidence is not so convinc- 



Fig. 2. 



Figure 2. — Protostega Copei, 1/7 natural size. Carapace of the type as 

 mounted in the Yale University Museum, from little crushed but dissociated 

 elements lacking those portions marked by an ( x ) or else given in dotted 

 outline. The portions actually present thus include a fine nuchal (with a 

 nether process), the four first neurals and pygal with the three first margin- 

 als perfect, together with eight pairs of pleuralia. The disk is then correctly 

 indicated ; but concerning doubts as to the existence of a large ninth pair 

 of ribs in contact with the marginals consult the text. 



ing and complete as in Archelon, where the series of ribs is not 

 only entire, but articulated. Nevertheless, owing to absence 



