CAMBRIAN FOSSILS. 465 



Fragments of the free cheeks associated with the glabella show that 

 they are convex and that the strong rounded rim is separated from the 

 cheek proper by a well-marked groove. 



The entire surface of the head, with the exception of the occipital 

 groove and the groove within the outer rim, is strongly pustulose, the 

 pustules being scattered irregularly over the surface. Where the true test 

 is broken away the pustules are shown on the surface of the cast. 



This species resembles Batliyurus conicus Billings, from the Calciferous 

 formation of northeastern. New York and St. Timothy, Canada. It differs, 

 however, in the strongly marked frontal rim and the form of the glabella. 1 

 It ma)' be also compared with Hall and Whitfield's Crepicephalus (L.) 

 maculosus. 2 



Formation and locality: Middle Cambrian, Flathead formation, Crow- 

 foot section, Gallatin Range, Yellowstone National Park. 



ZACONTHOIDES Walcott. 



Zaconthoides sp. undet. 



PI. LXV, fig. 3. 



Head moderately convex ; glabella convex, subclavate, narrowing 

 very slightly from the anterior toward the posterior end; marked by three 

 pairs of slightly impressed glabella furrows, the posterior pair cutting in 

 obliquely backward toward the occipital furrow. Occipital furrow narrow, 

 but distinctly impressed; occipital ring strong and provided with a short 

 strong spine, which projects from the upper posterior margin; fixed cheeks 

 narrow anteriorly and a little less than half the width of the glabella 

 opposite the posterior margin of the palpebral lobe; anteriorly they pass 

 down to the frontal rim, there being practically no frontal limb, the glabella 

 extending directly down to the margin The palpebral lobe is nearly 

 half the length of the glabella; anteriorly it extends to a point opposite the 

 anterior glabella furrow and posteriorly to a point opposite the occipital 

 furrow. 



The largest specimen of this species is 3 mm. in length; a second, a 

 smaller one, occurs on the same piece of limestone. It is possible that they 



' Geol. Surv. Canada, Pal. Fossils, Vol. I, 1865, p. 353, fig. 341ft. 

 2 U. S. Geol. Expl. Fortieth Par., Vol. IV, 1877, p. 215, PL II, lig. 24. 

 MON XXXII, PT II 30 



