Raymond : Notes on Ordovician Trilobites. 4 1 



Picrreruc and L'Chinian, Ilerault, I'lance, by Monsieur Jean Miquel. 

 The horizon was in the middle of the Tremador. The holotype is in the 

 Carnegie Museum. 



Genus NiOBE Angelin. 



Subgenus Hemigyraspis nov. 



This suljgcnus is proposed for A.saf)lildce with entire hypostoma, smooth, 

 undefined glabella which does not reach to the anterior margin, no glabellar 

 furrows and no neck-ring, facial sutures whose anterior limbs cut the 

 frontal margin in front of the eye (Niobiform), thorax with narrow axial 

 lobe, pygidium semicircular and nearly ribless. Type, Asaphus affinis 

 McCoy, as described by Salter, "Monograph British Silurian Trilobites," 

 PI. XXIV, figs. 13, 14, p. 164. 



Members of this subgenus are very similar to the species of Asaphellus, 

 but the facial sutures are of different types in the two. Hemigyraspis 

 is similar to Niobe, but the glabella is not defined by dorsal furrows as in 

 that genus, there is no neck-ring, there are spines at the genal angles, and 

 the pygidium is nearly smooth. 



Beside the type species, Ogygia desiderata Barrande, Niobe menapiensis 

 Hicks, and A', solvensis Hicks, all of which have been referred to Asaphellus 

 by Brogger, and Asaphellus? planus Ma thcw appear to belong to this 

 subgenus. 



Hemigyraspis collieana sp. nov. 



Plate XIV, figures 9-13. 



Asaphus marginalis Collie, Bulletin Geological Society of America, XIV, 1903, 



413. (In faunal lists.) Not of Hall. 



In the section at Bellefonte, Center County, Pennsylvania, Professor 



Collie found a zone 937 feet above the base of the exposed Beekmantown, 



and 3,866 feet below the top of that formation, in which an Asaphid was 



very abundant. The trilobite was supposed to be Asaphus marginalis 



Hall, a species which was very imperfectly known at that time. Professor 



Collie very kindly gave the writer a number of specimens of this trilobite, 



and among them I find a small unforked hypostoma, showing that this 



species can not be referred to the same genus as Asaphus marginalis 



{Basilicas). 



Description. 



Cephalon short and wide, glabella smooth, not outlined, no glabellar 

 furrows. Neck-furrow shallow, hardly visible. Eyes nearly halfway to 

 the front of the cephalon, large, very far apart. Between the eyes is a 

 small median tubercle. Free cheeks short, wide, with long narrow spines 



