476 



DR F. A. BATHER. 



Since the two faces of 6a are now known, it seems advisable to select that 

 individual as holotype. The selection is not without importance, because the species 

 is in any case closely allied to P. Rugeri, and in regard to ornament that species 

 comes midway between the two specimens of P. anglica, so that one or other of them 

 might conceivably be regarded as a synonym of P. Rugeri, and if that one were the 

 holotype, a new name would be required for the other. 



§ 469. Description of the Specimens. — Since these are somewhat difficult of 

 interpretation, and since my interpretation differs in a few points from that of 

 Prof. Jaekel, it is necessary to deal with them individually. 



In specimen 6 (PI. V. fig. 60 ; text-fig. 7Q) the plates visible on the antanal face 

 are : in Circlet I., 3, 4, 1, and part of 2, the last not shown by Jaekel ; in Circlet II., 

 8, 9, 5, 6, and apparently the lower part of 7 ; in Circlet III., the lower parts of 10 

 and 11. Plates 14 and 12 and all the plates of Circlets IV. and V. are broken away. 





(2/n l^y'^ 



Fig. 76. 



Fig. 77. 



Fig. 78. 



Text-figs. 76-78. — Pleurocystis anglica. Keys to the arrangement of the plates in the photographs 



on PI. V. X 3/2 diameters. 



Fig. 76 = pi. -fig. 60. — Paratype, in Riksmuseura, Stockholm. 



Fig. 77 = pi. -fig. 62. — Counterpart of Holotype, 25704 Mus. Pract. Geol. In the plate the periproctals are 



seen, but in this diagram they are omitted, and only the outlines of the underlying plates of the antanal 



side, as seen from within, are inserted. 

 Fig. 78 = Pl.-fig. 61. — Holotype, in Riksmuseum, Stockholm. 



The lower part of 14 with its half of the pectinirhomb is shown in Jaekel's figure; 

 but either this is a restoration or the plate has since been destroyed. In either case 

 the drawing of that plate appears incorrect, and this opinion is confirmed by the 

 incorrect rendering of the outer margin of plate 9 (erroneously lettered /4, instead of 

 Z3 ; see § 368). The theca, as a whole, is a little crushed and bent on itself between 

 plates 5 and 6. 



In specimen 6a (PI. V. fig. 62 ; text-fig. 77) the plates of the frame visible are, 

 from left to right: part of 12, the corner of 6, 7, 2, 3, 8, and perhaps part of 9. 

 Through the periproctal plating can be discerned the outlines of 6, 5, 9, 1, and 4. 



In 25704 (PI. V. fig. 61 ; text-fig. 78) the first three Circlets have left their 

 imprints, but the plates had previously been displaced. 



§ 470. Making allowance for the disturbance in the two specimens, and checking 

 our observations by 6a, we note that the greatest width of the theca lies between the 

 umbones of plates 8 and 7, being ca. 27 mm. in 25704 and not less in 6. From this 



