DESCRIPTION OF GENERA AND SPECIES* , 



Order I. HYPOPARIA Beecher. 



"Free cheeks forming a continuous marginal ventral plate 

 of the cephalon, and in some forms also extending over the 

 dorsal side at the genal angles. Sutures ventral, marginal or 

 submarginal. Compound paired eyes absent; simple eyes may 

 occur on each fixed cheek, singly or in pairs." Beecher, Zittel- 

 Eastman Text Book of Paleontology, p. 623. 



Family 1. HARPEDIDAE Barrande. 



"Cephalon large, with a broad marginal expansion or 

 limb; glabella short and prominent. Free cheeks ventral, 

 continuous; suture marginal, following the outer edge of the 

 limb. Paired simple eye-spots or ocelli, single or double, at 

 the distal ends of w r ell-marked eye-lines on the fixed cheeks, 

 extending outward from the glabella. Thorax of from twenty- 

 five to twenty-nine segments, with long grooved pleura. Pyg- 

 idium (in Harpes) very small, composed of but three or four 

 segments. ' ' Beecher, Zittel- Eastman Text Book of Paleontology , 

 p. 625. 



Genus i. HARPES Goldfuss, 1839. 

 Cephafon large, horse-shoe shaped, strongly convex cen- 

 trally with a broad flattened marginal expansion or limb which 

 is produced posteriorly into long, flat, pointed genal spines. 

 Glabella short, prominent, rounded or sub-truncate in front 

 with a single pair of small lateral lobes posteriorly or a single 

 transverse segment. Ocelli situated on the cheeks on either 

 side of the glabella near its anterior end and connected with the 

 glabella by raised eye-lines. Thorax conspicuously trilobate, 

 thoracic segments twenty- five to twenty-nine, with long grooved 

 pleura. Pygidium very small, composed of but three or four 

 segments. 



Harpes telleri, n. sp., pi. xx, fig. 2. 



Description. Cephalon horse-shoe-shaped, with a broad, 

 slightly concave marginal border or limb which passes pos- 

 teriorly, with its entire width, into the prominent flat genal 

 spines; the width of the limb at the sides and front of the head 

 is equal, but the genal processes become gradually narrower 



*For bibliography of the species described here, see the bibliographic list in the earlier 

 portion of the Bulletin. 



