42 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 76 



Figure 18 is of a cranidium that obviously has been distorted by 

 reduction of its original transverse dimensions. Its interest lies 

 particularly in the presevation and clear separation of the two pairs 

 of anterior spines. These spines are only very obscurely indicated 

 in the holotype of the species shown beside it in Figure 17. 



Figure 19 is an untouched photograph of a distorted and incom- 

 plete free cheek. It probably belongs to this species, this opinion 

 being mainly based on the fact that it reminds of the cheeks of 

 T. mohergi and T. hipunctatus^ both of which must on other grounds 

 be viewed as close allies of T. troedssoni. 



Figure 20 also is an untouched photograph of a cranidium that 

 can be referred to this species only provisionally. Though doubtless 

 much distorted by compression that has reduced its original longi- 

 tudinal dimensions by perhaps as much as a third, it is hardly con- 

 ceivable that its present shape could have been achieved by compres- 

 sion of a cranidium like that of either Figure 17 or 18 in the same 

 plate. Though the surface of the glabella shows some irregular un- 

 dulations none of the slight depressions could represent the dimple- 

 like furrows that occur on those cranidia. It probably represents a 

 form more nearly like that of such younger species as T. hircinus 

 and T. tellicoensis, in which the glabella is without furrows. 



Figure 21 is taken from an associated pygidium. Though the 

 original indicates reduction in length by compression of the shaly 

 matrix the width of the border behind the axis is still notably greater 

 than in any other species of the genus of which the pygidium is 

 known. Though possibly the tail of the associated T. huttsi its ref- 

 erence to T. troedssoni seems the most likely to prove correct. 



Plesiotypes.—C2ii. No. 80477, U.S.N.M. 



Genus GLAPHURUS Raymond 



GLAPHURUS PUSTULATUS (Walcott) 



Plate 7, Figures 15, 16, Plate 8, Figures 1-11. 



Arionellus pustulatus Walcott, 1880, 31st Ann. Rep, New York State Mus. 



Nat. Hist, p. 68 ; adv. sheets of same 1877, p. 15. 

 Sao (?)Lamottensis Whitfield, 1886, Bull. Amer. Mus. Nat. Hist., 1. p. 



334, pi. 33, figs. 9-11.— Brainerd and Seely, 1890, Bull. Amer. Mus. 



Nat. Hist., 3, p. 22.— Lesley, 1889, Geol. Surv. Pennsylvania Rep., P. 



4, p. 825, figs, (copied from Whitfield.) 

 Agraiilos {Arionellus} pustulatus Vogdes, 1890, Bull. U. S. Geol. Surv., No. 



63, p. 90. 

 Glaphurus pustulatus Raymond, 1905, Ann Carnegie Mus., vol. 3, p. 357, pi. 



14, figs. 4-6; 1910, vol. 7, p. 74, pi. 18, figs. 9-11; 1910, 7th Report 



Vermont State Geol., p. 234, pi. 36, figs. 4-6, and pi. 38, figs 9-11 ; also 



Grabau and Shimer, 1910, and Perkins, 1912, who reproduces Raymond's 



figures of the species. 



As the previously published illustrations of this interesting and 

 extremely spinose trilobite are not very good and fail to bring out 



