﻿48 MR. E. S. COBBOLD ON TRILOBITES FROM [Feb. I9IO r 



I would take this opportunity of very gratefully acknowledging 

 my indebtedness to Mr. Philip Lake, who kindly examined a great 

 number of my specimens and advised me as to their relationships. 



I am also indebted to Mr. W. Eupert Jones for very kindly 

 supplying me with most of the references in this paper, in addition 

 to his trouble in looking out and sending me works of reference from 

 the Library of the Society. 



EXPLANATION OF PLATES III-VIII. 



[The numbers in squai*e brackets are those attached to the individual 

 specimens. Unless otherwise stated, all the specimens are in niy collec- 

 tion for the Geological Excavations Committee of the British Association.] 



Plate III. 



[The minute figures are of the natural size, the enlargements are to 

 5 diameters.] 



Microdiscus comleycnsis, sp. nov. — Uppermost band of the grey limestones^ 

 Comley. (See p. 21.) 

 Figs. 1 & 2. Cephala [479, 478], exteriors. 

 Fig. 3. Pygidium [507], exterior. 



4. Pygidium [508], showing internal cast of axis. 



Ptychoparia (?) annio, sp. nov. — Olenellus Limestone, Comley. (See p. 24.) 

 Figs. 5 & 6. Cranidia [402, 403], exteriors. 

 Fig. 7. Cranidium [401], internal cast. 



8. Cranidium ; restored outline ; the parts shown by broken lines are 

 hypothetical. 



Micmacca (!) parvida, sp. nov. — Olenellus Limestone, Comley. (See p. 30.) 

 Fig. 9. Cranidium [412], internal cast. 

 10. Cranidium [411], exterior. 



Ptychoparia (?) attlcborensis, Sh. & F. — Olenellus Limestone, Comley. (See- 

 p. 23.) 

 Figs. 11 & 12. Cranidia [406, 405], exteriors. 

 Fig. 13. Cranidium [576], internal cast. 



Figs. 14, 15, & 16. Microdiscus hclena, Walcott. — Olenellus Limestone, Comley. 

 (See p. 23.) 

 Pygiclia [385, 386, 387]. test partly preserved. 



Microdiscus lobatus, Hall. — Uppermost band of the grey limestone, Comley. 

 (See p. 22.) 

 Fig. 17. Cephalon [453], exterior. 

 18. Pygidium [445], exterior. 



Plate IV. 

 Agraulos (Strenuella) saloj>iensis, sp. nov. (See p. 31.) 

 Fig. 1. Cranidium [161] ; from above, from behind, and from the right X 3, 

 and natural size from above. 



2. An anterior thoracic segment [164] ; from above, from behind, and 



from the right X 3, and natural size from behind. 



3. A median thoracic segment [162], showing base of spine ; from above, 



from behind, and from the right X 3, and natural size from 

 behind. 



4. A smaller and, possibly, more posterior thoracic segment [176] ; from 



behind and from the right X 3, and natural size from behind. 



5. Pygidium [274], probably belonging to this species ; from above, 



from behind, and from the right X 3, and natural size from above. 



