l6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I48 



anterior glabellar lobe barely rising above the cheeks ; posterior lobe 

 extended into a broad spine tilted at about 30° ; the spine appears to 

 be bluntly terminated, although this portion is not well preserved in 

 any of the cephala. The cephalic margin lies approximately in a 

 plane. The pygidial axis has rings well defined by straight ring fur- 

 rows becoming gradually shallower toward the rear, deeper 

 medially, and shallower near the axial furrows. The axis does not 

 reach the posterior border, although it appears almost to do so in 

 dorsal view on account of the strongly downsloping marginal por- 

 tions of the pleural regions. The excessively narrow lateral border 

 furrow and border maintain an almost even width throughout. The 

 anterior border furrow instead is relatively wide; the anterior py- 

 gidial margin has a straight transverse course from the axial furrow 

 to the geniculation, which is closer to the lateral margin than to the 

 axial furrow. The facet is well developed. 



The surface of the test is finely punctate, this ornamentation both 

 in the cephalon and pygidium being more marked on the pleural 

 than the axial parts. Length of the larger cephala, exclusive of 

 glabellar spine, 4 mm, width 5 mm. Length of largest pygidium 

 3.5 mm, width 4 mm. 



Occurrence. — Collection cs-4. North Chatham. 



Types.— Uolotype: U.S.N.M. 145093. Paratypes: U.S.N.M. 

 145094. 



BATHYDISCTTS Rasetti, ne-w genus 



Description. — Cephalon with considerable relief. Glabella with 

 almost undifferentiated occipital ring prominent, slightly expanded 

 forward, reaching the anterior border, unfurrowed. Cheeks convex 

 and downsloping. Border convex, wide, well defined by a border 

 furrow inbent on either side of the anterior portion of the glabella 

 to merge with the axial furrow. In anterior view, the medial por- 

 tion of the border is seen to be slightly arched, instead of lying in a 

 plane as in most Eodiscids. Posterior cephalic border with sharp 

 geniculation and short, erect spine located close to axial furrow as 

 in Oodiscus. Surface of test smooth. 



Pygidium tentatively assigned to the type species with long, well- 

 defined, unfurrowed axis not reaching the border furrow. Border 

 furrow narrow laterally, widened posteriorly ; border narrow, slightly 

 elevated. Doublure not reflexed to parallel the dorsal exoskeleton as 

 in most Eodiscids, but almost vertical, with a slight inward slope, 

 wide everywhere except in the posteriormost portion. This attitude 

 of the doublure gives the pygidium as a whole an unusual depth. 



