October, 1913. New Trilobites — Slocom 63 



The species is known from the holotype (Mus. No. P 17038) in which 

 the cephalon, about two-thirds of the thorax and most of the pygidium 

 are preserved, from five detached pygidia and from one specimen in 

 which the entire pygidium is attached to all but the anterior segment of 

 the thorax. 



In general form and proportions the species here described resembles 

 E. variolans, Brongniart from the Wenlock Limestone of England, but 

 the tubercles are much larger, the transverse furrow on the glabella is 

 missing and the annulations of the pygidia are fewer in number. E. 

 sexcostatus Salter possesses the transverse furrow, but that seems to be 

 about the only resemblance with this species. 



Locality and horizon. — The holotype is from the top of the Lower 

 Maquoketa beds at Bloomfield. The species has been found at a 

 similar horizon at Clermont and Elgin, and at a somewhat lower 

 horizon at Clermont. 



Genus CYBELOIDES gen. nov. 



Body distinctly trilobate, outline, aside from the spines, sub-ovate. 

 Cephalon sub-lunate ; genal angles produced into spines. Glabella 

 divided by two longitudinal furrows into a central and two lateral lobes; 

 the lateral glabella furrows are indicated by three pits situated in each 

 longitudinal furrow. Eyes small, pedunculate; the facial sutures 

 originate on the lateral margins somewhat in front of the genal angles. 

 Thorax consists of twelve segments; the five anterior segments are 

 faceted at their distal extremities. The sixth segment, and in some 

 specimens the sixth to the twelfth, is abruptly bent backward at the 

 lateral margin of the thorax and produced into long spines. Pygidium 

 small, axis conical with many annulations, pleural lobes with few ribs. 



Genotype, Cybeloides iowensis. Range, Ordovician of North 

 America. 



This genus differs from Cybele Loven as exhibited in C. bellatula, 

 the genotype, in the form of the glabella furrows and in the genal angles 

 being produced into spines instead of being rounded. 



Four American species have been referred to the genus Cybele; C. ella 

 Narraway and Raymond, C. prima (including C. valcourensis) Ray- 

 mond, C. winchelli Clarke, and a portion of a pygidium referred to the 

 genus without specific determination by Ruedemann. Of the first two 

 only is the form of the glabella known, but both of these agree with 

 C. iowensis here described. Narraway and Raymond called attention to 

 the difference of the form of the glabella of this species from that of the 

 European species, but still referred their species to Cybele. While the 



