﻿APTYCHOPSIS BARRANDEANA. 



101 



obovate forms come from the same geological origin, but in limestone at other 

 localities, as Butowitz, Slawick, and Wohrada, and rare at Kozel. 



We think that " secunda " will serve as a varietal name for the round or 

 nearly-round forms, as suggested by us in the ' Geol. Mag.,' 1884, pages 349 and 

 354, and « Report Brit. Assoc. for 1884 ' (1885), pages 76 and 89 ; M. Barrande's 

 term " Aptychopsis prima " being kept for the obovate carapaces; and, if the oval 

 form (fig. 17 of Barrande's plate) matches A. Lapworthi, H. W., it is already 

 provided with a specific appellation. 



Taking A. prima, or the subcircular-obovate form, as typical, on the evidence 

 of the labelled Bohemian specimens in the British Museum (see woodcut, Fig. 7), 

 we know them as having carapaces 25 to 32 mm. long, by 23 to 33 mm. wide, and 

 with the nuchal suture having an angle of about 90° or 100°. See Barrande's 

 figs. 10, 12, 16, 19 — 21. His fig. 11 may be regarded as A. prima, var. longa (34 

 by 28 mm.). 



2. Aptychopsis Barrandeana, sp. nov. Plate XV, fig. 1 ; and var. brevior, fig. 14. 



At first we regarded our specimens PI. XV, figs. 1 and 14, as being A. prima, 

 Barrande ; but we now distinguish important differences between the forms. 



The two specimens in the British Museum, in limestone from Bubowitz, 

 and labelled " Aptychus ? primus " by M. Barrande, have (if complete) the obovate 

 shape of several of Barrande's figures, and more particularly correspond to his 

 fig. 19. Our fig. 1 is longer and proportionally narrower at the posterior third 

 than any of the Bohemian specimens or figures ; so also our fig. 14 (variety) is 

 much narrower posteriorly, with a straight and more sloping outer margin, com- 

 pared with any of them. They both also have a shallower and wider notch than 

 the Bohemian forms. 



This large and distinct species is here named in honour of the eminent pateeon- 

 tologist of Bohemia, who was one of the first to give attention to these phyllo- 

 podous fossils. 



PI. XV, fig. 1, is a large left valve, imperfect from the loss of a considerable 

 portion of its upper outer angle ; part, however, of the left nuchal slope is 

 distinct, with a very low angle. Measurements : 1 the dorsal suture is 31 mm. 



1 To save trouble the following arrangement of signs may be adopted : 

 For the vertical suture I 

 For the breadth of a single valve — 

 For the left side of the notch A 

 For the right side of the notch l_ 

 For the width or gape of the notch w 

 For the depth of the notch I 

 For the angle of the notch v 



