20 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



the ornamentation of the pleura is similar to that of the cephalon. 

 On each side of the axis there is an oblique furrow, directed outward 

 and forward, reaching the axial furrow at the anterior corner of the 

 ring. The pleura is flat and horizontal for most of its length, with a 

 furrow paralleling and close to the posterior margin. The anterior 

 margin has a very sharp geniculation, where it bends backward and 

 downward, forming a marked facet. At the fulcrum a very narrow 

 ridge is set off near the anterior margin by a shallow furrow, a feature 

 also observed in Serrodiscus subclavatus. The distal end forms a 

 short, sharp spine directed outward and backward. 



Occurrence. — Collection cs-4. North Chatham. 



Types.— Holotype: U.S.N.M. 145998. Paratypes: U.S.N.M. 

 145999. 



BOLBOPARIA ELONGATA Rasetti, new species 

 Plate 3, figure 2 ; plate 5, figures 7-12 



Available material. — A few cephala, of which two reasonably 

 complete, and three tentatively assigned, incomplete pygidia. 



Description. — The cephalon is so similar to the type species 

 that it is sufficient to point out the differences. Cephalon somewhat 

 longer than wide. Glabella proportionately narrower and longer 

 than in B. superba, bearing the same kind of lateral furrow and 

 posterior spine. Anterior cephalic outline somewhat more sharply 

 pointed; cheeks bulging anteriorly but not as much as in the type 

 species ; outline at the anterolateral corners turning even more abruptly 

 than in that species. Posterior portion of border furrow even more 

 oblique than in B. superba, forming an angle of 45° with the axis 

 of the body. Widened posterior portion of lateral border bearing two 

 pairs of tubercles as in preceding species. Genal angle not well pre- 

 served. Length of largest cephalon 8 mm. Ornamentation as in pre- 

 ceding species. 



Three incomplete examples of a pygidium undoubtedly belong to 

 Bolboparia as they match the unique ornamentation of the cephala. 

 However, the reference to B. elongata rather than B. superba, sug- 

 gested by the relatively narrow shape, is tentative. Axis moderately 

 wide, slightly tapered, defined by deep axial furrows, almost reaching 

 the posterior border, furrowed for entire length, showing approxi- 

 mately 12 rings ; end portion not well preserved. A broad-based 

 spine on the second ring encroaches on the adjacent ring furrows. 

 Pleural regions attaining a vertical slope, almost concealing the bor- 

 der in dorsal view. Border furrow well impressed ; border vertical, 



