60 BRITISH PALAEOZOIC PHYLLOCARIDA. 



partly calcareous ; casts of small Brachiopoda and Cardiola interrupta are present 

 on a bed-plane. It differs very much from Physocaris vesica, although nearly of 

 the same size. The carapace is subtriangular, 25 mm. long and 14 mm. deep at 

 the middle of the ventral margin (PI. VII, fig. 6.) The back is straight, but curved 

 down at both ends to meet the steep upward slopes of the lower margin. The 

 abdomen (15 mm. long) comes out, as usual, from the upper part of the hinder 

 region. The carapace is represented by a thin, brownish, wrinkled film ; the irre- 

 gular crumpling in the antero-dorsal region is probably due to the presence of 

 hard remains of internal organs. [The front extremity is not quite so distinct as 

 in the drawing.] Pour body-segments and a small part of the caudal appendages 

 remain attached. The ultimate (6 mm.) and penultimate segments retain their 

 test, which is obliquely striated. 



Specimen Ludlow Mus. J (from Trippleton, near Leintwardine) has a smaller 

 but nearly similar carapace (22 X 12 mm.), gently convex on the back, deeply 

 curved below, and with almost equal, sharp dorsal angles in front and behind. 



Specimen Ludlow Mus. K, from Trippleton, near Leintwardine, has a carapace 

 (23 X 12 mm.), five (?) abdominal segments (10 mm.), and appendages, of which 

 the style (pitted with bases of little spines) is imperfect, but a stylet measures 5 

 mm. (PI. VII, fig. 4). 



Much narrower than those above mentioned is B. M. 39400 (PI. Ill, fig. 9), 

 which has been squeezed, so as to have its outline modified. It is in olive-grey 

 micaceous mudstone, weathering brownish, from the Lower-Ludlow beds at 

 Church Hill, Leintwardine. 



The part of carapace preserved is much crumpled, but seems to have been 

 smooth. The converging wrinkles at the hinder end may have been altogether 

 due to pressure. There are some obscure indications of internal organs, including 

 an elongate, slightly curved, fimbriated, branchial (?) appendage, or displaced 

 antenna, lying lengthwise in the ventral region. There are also obscure remains 

 of abdominal segments and appendages, altogether about 17 mm. long. A hollow 

 cast belonging to the same species, B. M. 44342, from Benson Knot, has a better 

 preserved outline. It is nearly oblong, slightly arched above and below, truncate 

 with hollow curve behind, pointed and mucronate in front. In outline this 

 approaches PI. IV, fig. 7, but is larger and proportionally deeper. 



As in C. cassia so in C. cassioides, the carapace has been apparently thin and 

 tough, so as to allow of it being crumpled very much. This condition and the 

 presence of harder parts of their internal organs beneath give rise to various irre- 

 gularities of the surface, in some cases simulating ocular tubercles. There are, 

 however, no real eyespots. Some of the superficial derangements may be due to 

 the attachment of the muscles of the jaws within the carapace. 



PI. IV, fig. 7. Oxford Museum Q. Lower Ludlow. In the usual mudstone, 



