168 BRITISH PALAZOZOIC FOSSILS. [Crustacga. 
to the front margin ; eyes small, hiant, reniform, in the midst of the cheeks, opposite about the middle of the 
glabella ; eye-/ine continuous from one side to the other, all anterior to the eyes being nearly parallel with the 
margin of the buckler, pointed in front, forming the usual small outward lobes over each eye, and from thence to 
the lateral angles or a little in front of them ; thoraa slightly arched, imperfectly trilobed, of thirteen segments ; 
axis wider than the lateral lobes, which have subtruncate ends with large distinct facets; pleural sulcus as in 
Calymene, arising from the posterior margin near the undefined axis, and at half its length abruptly bent down 
again to it; pygidium subtrigonal, pointed, with a very narrow axis or none, the lateral ribs undivided. 
HloMALONOTUS BISULCATUS (Salt. in Ap.) Pl. 1.G. fig. 24 to 31. 
Sp. Ch.—Pygidium semielliptical, edge compressed, convex anterior margin widely arched, sides nearly 
straight, converging to an obtusely rounded termination; aais gradually tapering, nearly as wide as the side 
lobes, flat, indistinctly marked, not quite reaching the margin, eleven or twelve segmental furrows, the two 
anterior stronger than the rest; sees with about seven broad flat ribs, separated by narrow sulci, the two 
anterior of which are disproportionably deep furrows, the rest very shallow; surface smooth; pygidium from 
half to one and quarter inches in length. 
The disproportionate strength of the two anterior segmental furrows of the pygidium, and the obtusely 
rounded extremities, characterize this species well. There is a small variety in which only eight or nine seg- 
ments can be counted in the axis, and the first two furrows not so strongly marked. The head supposed to 
belong to this species has the glabella oblong, one-third longer than wide, distinctly bounded by a strong 
furrow at the sides, more obscurely in front. 
Position and Locality Caradoc sandstone of Acton Scott, Church Stretton, Shropshire; Alt yr Anker, 
Meifod, Montgomeryshire; Maes Meillion, S. of Bala, Merionethshire ; Ravenstone Dale, Westmoreland ; 
Capel Garmon, Denbighshire. 
Explanation of Figures —P\. 1. G. figs. 24 and 25. Portions of cephalic shield, natural size, from near 
Pwllheli.—Fig. 26. Pygidium and part of thorax (this specimen is not in the collection).—Figs. 27 and 28. 
Pygidia natural size, from near Acton Scott.—Fig. 29. Part of small cephalic shield.—Figs. 30 and 31. 
Pygidia of supposed varieties from Ravenstone Dale. 
Homatonotus KnicutTu (AGnig). 
Ref. and Syn.—H. Knightii Konig, Icon. Fos. See. H. Ludensis and H. Knightii Murch. Sil. Syst. 
teiMenenl 3725 
Sp. Ch.—Axis of the abdomen very wide and obscurely defined ; pygidiwm ovate, convex, anterior margin 
nearly semicircular, sides converging rapidly to a smooth, simple, undivided, subtrigonal pointed truncation ; 
about nine gently curved distinct, narrow segments, separated by strong sulci, the axal and lateral portions 
appearing continuous, a slight oblique depression on each side marking the axis. Average length of the pygi- 
dium nine lines, width one inch. 
Position and Locality—Upper Ludlow rock of Tenter Fell, Kendal, Westmoreland ; schists of Mid- 
dleton Park, near Sedburgh. 
HoMALonotus RUDIS (Salt. in Ap.) Pl. 1. E. fig. 20. 
Sp. Ch.—Pygidium semielliptical, elevated, axis defined by strong furrows, gradually tapering, convex, of 
about seven or eight strong nodulous segments; sides slightly convex, sloping downwards and outwards from 
the axis, of six strongly defined, broad, nodulous ribs. Length of pygidium about one and a quarter inches. 
One of the specimens seems to shew but three great ribs on the anterior half of the axis, and may possibly 
be distinct. 
Position and Locality.—In the coarse grey schists of Capel Garmon, Denbighshire. 
Explanation of Figures.—P|. 1. E. fig. 20. Pygidium, natural size—Fig. 20 a. Portion of much 
larger ditto. 
