RAYMOND: NEW AND OLD SILURIAN TRILOBITES. 19 



has short glabellar furrows and no lip on the free cheek, while B. dayi 

 has long furrows and a lip on the free cheek. The eye of B. decijnens 

 seems also to be a little longer and further back than in B. dayi. The 

 pits in front of the eyes are exceedingly faint. 



Buviastus transversalis (Weller) likewise has a short head, large 

 eyes, and short dorsal furrows, but is much wider than B. decipiens. 

 B. armatus (Hall) is much like B. decipiens but has spines at the genal 

 angles. 



Measurements: — The holotype (Plate 1, fig. 2) an imperfect 

 cranidium, is 19 mm. long; the eye is 7.5 mm. long, and 2 mm. from 

 the posterior margin. The figured paratype (Plate 1, fig. 1) is about 

 51 mm. long; cephalon 21 mm. long; thorax 15 mm. long. A second 

 small, unfigured paratype has the cephalon 12 mm. long, 16 mm. 

 wide; eye 5 mm. long; 1 mm. from posterior margin; thorax 8 mm. 

 long; pygidium 12 mm. long, and about 16 mm. wide. 



Formation and locality: — All the specimens are from the Niagaran 

 at Wauwatosa, Wise. 



BUMASTUS TENUIS, Sp. nOV. 



Plate 1, fig. 6, 7 and ? 11. 



This species is like B. decipiens, rare, and the collection contains 

 five specimens showing the cranidium only. It is characterized by 

 its slight convexity and the very wide concave lip at the front. The 

 dorsal furrows are long, reaching to the pit in front of the eyes. These 

 pits are themselves very far forward and close to the margin. The eyes 

 are large and close to the posterior margin. 



This species of course suggests B. cuniculus, but the lip is much 

 wider, the dorsal furrows longer, and the pits in which they end very 

 close to the margin. It has a flatter cephalon and wider lip than any 

 known Bumastus. 



A pygidium (Plate 1, fig. 11) which does not seem to belong with any 

 other species found at Wauwatosa is tentatively referred to B. tenuis. 

 It is too short and not convex enough for B. niagarensis, and has too 

 wide a concave border for B. cuniculus, B. dayi, or B. decipiens. 



Measurements: — The type cranidium is 33 mm. long and 34 mm. 

 wide at the palpebral lobes. The eye was approximately 8 mm. long 

 and 2 mm. from the posterior margin. 



Formation and locality: — All the specimens are from the Niagaran 

 at Wauwatosa, Wise. 



