552 Transactions of the Society. 



C. ploenensis A^oigt (50). Plate XXII, figs. 4a-45. 

 Syn. Distyla ploenensis Voigt. 



Description. — Large, oblong, dorsal plate broader, posterior 

 border narrow. Posterior lobe small, rounded. Anterior border 

 straight, bounded by small spines. Toes half length of lorica, from 

 broad base suddenly narrowed and near tlie points more rapidly 

 tapered. Lateral sulcus shallow, posterior deep. Dorsal plate 

 faceted. 



Length of contracted lorica 135 yu,, of dorsal plate 125 fj,, of toe 

 65 /i; breadth of dorsal plate 90 /a, of ventral plate 80//,, of ante- 

 rior border 65 /x. 



The dorsal plate is of the same width as the ventral in front, 

 so that the frontal spines belong to both. The dorsal facets form 

 the pattern commonest in the order, as in C. stokesii, C. ohioensis, 

 etc., but the proportions are peculiar, some of the anterior and pos- 

 terior facets being elongated at the expense of the middle ones. 



Habitat. — Scotland. 



C. signifera Jennings {^6). Plate XXIIT, figs 13«, 135. 



Description. — Fairly large. Dorsal plate broader. Anterior 

 margin flatly convex, between small curved spines. Posterior lobe 

 prominent. Toes long, slender, straight, acute, not shouldered. 

 Dorsal plate faceted, the facets bordered by large papillae. 



Length of contracted lorica 130 /a, of dorsal plate 110 /i,, of toe. 

 55 /i ; breadth of dorsal plate 85 yu,, of ventral plate 75 /i, of ante- 

 rior border 65 /a. 



The facets appear to- form a distinctive pattern, distinct from 

 that of C. stokesii or C. rnira, but I could not distinguish any ex- 

 cept those near the anterior and posterior borders. The papillae 

 also occur on the ventral surface, following the lines of the 

 wrinkles. 



Drawn from a specimen collected by Mr. Harring, and given 

 to me by Mr. Eousselet. 



Cathypna ohioe^isis Herrick (2^. Plate XXIII, figs. 14a, 14^. 



Description. — Of medium size, ovate, produced behind into 

 truncate process. Dorsal plate wider, tessellated. Anterior 

 margins straight, bounded by conspicuous spines. Toes short. 



Length of contracted lorica 135 yit, of dorsal plate 100 /a, of toe 

 35 yu, ; breadth of dorsal plate 80 /x, of ventral plate 70 /x, of anterior 

 margin 45 /x. 



The dorsal margin cannot be traced quite to the front. The 



