48 A Contribution to the Lower Devonian Faunas of Maryland 



broad, depressed, annulations ten or eleven, low and broad, arching broadly 

 anteriorly; plenr^e profoundly arched along fulcra and incurved at base, 

 each bearing ten annulations which are broad, low, nearly direct, and be- 

 coming obsolete distally. Dimensions of pygidium : Length about 82 

 mm.; width 72 mm. 



A cast of a pygidium, which is taken as the type of the species, was 

 discovered by Dr. C. K. Swartz and is named for him. In size this species 

 is comparable to H. major Whitfield. The above incomplete description 

 of the thorax is from a single thoracic segment from Miller's Spring, West 

 Virginia. The pygidium and the segment presumably belong to the same 

 species. Both occur in the Oriskany, and are of large proportions and the 

 fulcra are of about equal sharpness. 



Occurrence. — Oriskany For:mation, Eidgely Member. Sand quarry 

 4 miles southwest of Hancock (pygidium), Maryland; ^liller's Spring 

 (thoracic segment of glabella), West Virginia. 



Collection. — Maryland Geological Survey. 



HOMALONOTUS YANUXEMI Hall 



Plate LXXXIX, Figs. 13-15 ; Plate XC, Fig. 3 



Homalonotus vanuxemi Hall, 1859, Nat. Hist. N. Y., Pal., vol. iii, p. 352, pi. 



Ixxiil, figs. 9-14, 1861. 

 Homalonottis vanuxemi Hall and Clarke, 1888, iMclem, vol. vii, p. 11, pi. \b, 



figs. 1, 2. 

 Homalonottis vanuxemi Weller, 1903, Pal. N. J., vol. iii, p. 321, pi. xxxix, figs. 



7, 8; p. 338, pi. xliv, figs. 4-7. 



Description.—" Thorax long : sides subparallel, the middle lobe flat- 

 tened on the exterior surface : articulations arching forward ; longitudinal 

 furrows faintly defined, being a simple undulation in the articulations; 

 lateral lobes narrow, the articulations bent abruptly downwards at the 

 sides. Pygidium subtriangular witli tlie articulating side much longer 

 and broadly curving, extremely convex: axis prominent in the young 

 specimens, and becoming subdued in older ones; width, at its upper ex- 

 tremity, equal to that of each of the lateral lobes. Annulations fourteen 

 or fifteen in the cast, and twelve ribs visible on each of the lateral lobes. 

 Surface of the test punctate and striato-punctate : cast punctate." Hall, 

 1859. 



