ART. 21 OEDOVICIAN TEILOBITES ULEICH 25 



species. Some 40 cranidia of the latter, while indicating extraor- 

 dinary agreement among themselves, differ constantly from the fig- 

 ures of Norwegian and Swedish specimens referred to the former in 

 (1) the greater width, contour, and shape of the fixed cheek; (2) 

 in the inferior length, more regularly semieliiptical outline, and 

 greater median convexity of the glabella; (3) in the greater separa- 

 tion and less anterior position of the bases of the glabellar spines; 

 and (4) the presence of tubercles on the outer parts of the fixed 

 cheeks and the wider distribution of the tubercles on the glabella and 

 also on the occipital ring. Other less conspicuous differences will be 

 observed in comparing figures of the two species; the occipital 

 spine, for instance, seems to be stronger, whereas the ridge on the 

 free cheeks is not so sharp as indicated in Hadding's illustrations. 



Comparison of their respective pygidia discloses equally distinctive 

 peculiarities. Hadding's illustration of this plate in T, granulatus 

 shows two axial rings behind the anterior half ring, each of the two 

 with a single median tubercle or short spine and without other 

 tubercles. In T. hicornis^ on the other hand, a narrow tuberculated 

 third ring makes the posterior extremity of the axis, and each of the 

 two rings in front of it carries a pair of spines and besides these one 

 or two rows of tubercles between them and the dorsal furrows. 



The free cheeks, except for the large bulbous and beautifully 

 faceted eyes, are very narrow. Except at the genal angle only a 

 narrow smooth rim follows the outline of the eye. The genal spine 

 begins with a broadly swollen and outwardly rapidly tapering base, 

 its further extension being very long and slender, only slightly 

 curved, and obliquely striated. A much shorter spine lies just 

 behind it. 



Only two thoracic segments were found, and both consisted only of 

 the axial part. Though similarly covered with tubercles, one car- 

 ried the expected pair of median spines, but the other (see pi. 4, 

 fig. 14) had only one and this in the middle of the axis. The pleural 

 parts are short and apparently terminate bluntly. 



Because of the two glabellar horns it is not likely that reasonably 

 complete cranidia of this species will be confused with any of the 

 other species here described. A like statement regarding the free 

 cheeks and pygidia would scarcely be warranted because we know 

 these parts of only a few of the species. But they are surely quite 

 distinct from the few other kinds of Telephu^ free cheeks and pygidia 

 that have been discovered. That those referred to T. hicornh actu- 

 ally belong to this species is rendered fairly certain by the fact that 

 whereas cranidia were abundant in a thin layer at the type locality 

 no other species of the genus was found either with them or in any 

 other bed at this place. 



