ART. 21 ORDOVICIAN TRILOBITES ULRICH 29 



Occwrejice.— The types were found in the Whitesburg limestone 

 at Lexington, Va. With them occurred a specimen agreeing in ali 

 respects except the glabella, which is a trifle longer. Another crani- 

 dium was found in the same formation near Albany, Tenn. The 

 latter being somewhat distorted by pressure I could not decide 

 whether its structure is more like that of the types of the species or 

 like the second variety. 



Holotypes and paratopes. — Cat. No. 80536, U.S.N.M. 



TELEPHUS SPINIFERUS, new species 



Plate 3, Figure 11 



The holotype of this species — a rather well-preserved cranidium — 

 has only about half the width from palpebral edge to palpebral edge 

 as do the specimens of T. latus with which it was found. If differs 

 also very decidedly when details of structure are compared. In the 

 first place, whereas T. latus has a very short occipital spine the 

 corresponding spine on T. spiniferus is stronger and much longer, 

 its length being nearly equal to that of the glabella in front of the 

 occipital furrow. Next, the fixed cheeks are wider in front and ex- 

 tend forward beyond the anterior extremity of the glabella. In con- 

 sequence the anterior outline of the cranidium is different, being 

 slightly but definitely concave in its inner three-fifths and the whole 

 anterior and lateral parts of the outline much less convexly bowed. 

 The antero-lateral outline of the convex areas of the fixed cheeks 

 and also of the palpebral bands is more sharply curved. Third, the 

 convexity of the whole and particularly of the glabella is relatively 

 less in T. spiniferus even when the slight vertical compression of the 

 specimens is taken into account. Finally, the tubercles of the sur- 

 face of the glabella and over the anterior half or more of the convex 

 areas of the fixed cheeks though smaller are more distinct and more 

 numerous, and those on the middle half of the glabella exhibit a 

 more regular arrangement in anteriorly slightly diverging rows. 



The unusual length of the occipital spine and the longitudinal 

 arrangement of the surface tubercles on the middle of the glabella 

 will distinguish this species at once from most if not all others of 

 the genus. A long spine occurs also in one of the varieties of 

 T. hipunctatus and in other species — notably in T. troedssoni and 

 T. huttsi — but in all these cases the differences in other respects are 

 too conspicuous to be likely to cause confusion. 



Occurrence. — The holotype was found in association with Telephus 

 latus, Rohergia major Raymond, and graptolites of several species 

 in the limy basal part of the Athens shale overlying Holston lime- 

 stone in the large quarry 3 miles southeast of Saltville, Va. 



Holotype.— Q^t. No. 80537, U. S. N. M. 



