ART. 21 OBDOVICIAN TRILOBITES ULRICH 31 



as separating closely allied but distinguishable forms will add one 

 more to the list of useful guide fossils. Besides, it is thought even 

 likely that the form which it is proposed to call Telephus sinuatus 

 is really more closely allied to T. bipunctatus and T. mysticensis 

 than T. spiniferus. 



The occipital spine in the holotype of T. sinuatus is broken, but 

 enough remains to indicate a length and direction similar to that of 

 the corresponding spine in T. spiniferus. As said the outline and 

 convexity of the glabella also is not strikingly different except in its 

 posterior part. Namely, the anterior side of the neck furrow is not 

 straight as usually is the case in species of Telephus but curves back- 

 ward on either side of the middle third, the undulations being due 

 to the imperfect development of a pair of posterior glabellar lobes. 

 The neck furrow therefore is curved in a manner simulating a 

 " Cupid's bow." Other more obscure marks in the slopes of the 

 glabella and which doubtless are related to glabellar furrows are 

 shown in the illustrations in Plate 3, but, as will be observed, there 

 is nothing like the distinct pair of dimples which are so characteristic 

 of T. hipunctatus. In fact, although clearly outlined the middle part 

 of the spots is slightly raised instead of deeply impressed. 



In the anterior and lateral parts of the outline of the cranidium 

 and in the shape and size of the fixed cheeks T. sinuatus agrees much 

 better with T. mysticensis and T. gelasinosus than with either T. 

 spiniferus or T. hipunctatus^ the general outline being more rounded 

 and the fixed cheeks smaller than in the latter two species. 



Occurrence. — The holotype and only known specimen was found in 

 the Whitesburg limestone at Lexington, Va. The Whitesburg in the 

 vicinity of Lexington is very fossiliferous. After years of collecting 

 the total fauna from this bed and place comprises more than 80 

 species, 30 of them trilobites. 



Holotype.— C2it. No. 80540, U.S.N.M. 



TELEPHUS BIPUNCTATUS, new species 



Plate 5, Figures 1-9 



This is by far the most abundant and most widely distributed of 

 the American species of Telephus. It is very constant in its char- 

 acters and perhaps also the best marked. In view of the excellent, 

 and in every respect sufficient, illustrations given on Plate 5 it seems 

 unnecessary to supplement these with a detailed description. How- 

 ever, the more desirable comparisons with other species should not 

 be omitted. 



Compared with previously described species only one is at all 

 closely allied to T. hipimctatus. This is the Swedish T. mohergi 

 Hadding, which also has depressions or pits in the lateral slopes 



