42 MR. E. S. COBBOLD ON THE TRILOBITE FAUNA [March 1913,. 



Olenellus (sensu Into) has been recently divided by Dr. Walcott. 1 In 

 only one species, Olenellus argentus Walcott, is it entirely replaced 

 by another form of surface, a strongly granular one, and even this 

 he regards 2 as but an extreme modification of original reticu- 

 lation. Two other species, Hohnia roivei "Walcott 3 and Weinneriet 

 gracilis Walcott, 4 have a granular surface on parts of the test, but 

 this is accompanied by a set of fine raised lines. 



The same, or a very similar, reticulation is found in Bathynotus- 

 holopyge Hall, in Conocoryphe (Atops) reticulata Walcott, in a 

 slightly modified form in Avedoniet manuelensis Walcott, and in the 

 Comley species Mohicana claveita Cobbold. 



If this character of test is a primitive feature, it seems inter- 

 esting to find it in a Dorypyge of Middle Cambrian age. 



I cannot close this communication without expressing my in- 

 debtedness to Prof. J. C. Moberg, who very kindly sent me copies 

 of the English translations of his Geological Guide to Andrarum, etc. 5 

 and of his ' Historical- Stratigraphical Review of the Silurian of 

 Sweden,' 6 prepared on the occasion of the Xlth International 

 Geological Congress, 1910. They have been of great use, not only 

 for the excellent bibliographies which they include, but also as- 

 giving a clear resume of the work of previous authors. 



I am also indebted to Prof. K. A. Gronwall for gifts of publi- 

 cations dealing with Swedish Cambrian horizons, and especially 

 for his kindness in sending me a copy of his ' Bornholms Peira- 

 clo.videslag' 1902. 



To Prof. Charles Lapworth I am again greatly indebted for 

 continued help and encouragement. 



EXPLANATION OF PLATES II & III. 

 Plate II. 

 [All the figures are enlarged, except fig. 2, which is of the natural size.] 

 Pamdoxides intermedins, sp. nov. (See pp. 29-31.) 

 Fig. 1. Internal cast of cranidium with left cheek flattened, and part of the- 

 external cast of the doublure visible on the right [1832] : a, view 

 from above ; b, side view ; c, view from behind, with the convexity of 

 the left cheek restored ; all X 2. 



2. Fragmentary free cheek of a much larger individual with test partly 



preserved [1435] : referred with doubt to the species ; natural size. 



3. Internal cast of cranidium [1S28] : the left front and side are bent 



down, and buried in the rock; X 2. 



4. Internal cast of fragmentary glabella [1440], referred with reserve to- 



P. ruguhsus Corda in Rep. Brit. Assoc. 1912 (Dundee). 



5. Internal cast of fragmentary hypostoma [1449], with some portions- 



restored from the counterpart [1450] ; X 2. 



6. Internal cast of termination of pleura [1454] ; X 2. 



1 C. D. Walcott, Smithsonian Misc. Coll. vol. liii, no. 6, 1910. 



2 Ibid. p. 315. 3 Ibid. p. 294. ■* Ibid. p. 299. 



9 Geol. Foren. Stockholm Forhandl. vol. xxxii (1910) pt. 1, pp. 45-194. 

 6 Sver. Geol. Undersokn. ser. O, No. 229 (1910). 



