16 DEVONIAN FAUNA. 



Free cheek small, bearing the short, thick cheek-spine. Border prominent, deep, 

 circular in section, preceded by a furrow where not actually overhung by the 

 glabella, and ornamented by three strong grooves between sharpish ridges. Neck- 

 lobe very broad and arched, extending half-way behind the fixed cheek. Lateral 

 processes of the neck bent rather forward. Outer layer of test thick. 



Size of Head. — 10 mm. in length, 32 mm. in breadth, 8 mm. in depth. 



Locality. — Lummaton. I have obtained three specimens, and there is another 

 in the Lee Collection in the British Museum. 



Remarks. — The specimen figured is the only one that shows the characters 

 well. It originally retained the eye, but this was accidentally destroyed before it 

 was figured, and that part has therefore been restored from a rough drawing I 

 had made. This fossil had been a little distorted by pressure, and consequently 

 may appear to be rather wider than it actually is. The extremity of the cheek is 

 also very much obscured, and is consequently difficult to understand exactly. 



The only Bohemian species which at all resembles it is Lichas Haueri, Barr., 1 

 but it differs from that species in most of its details. For instance, the border is 

 stronger, and is grooved instead of punctated, the head is much wider, the frontal 

 lobe ends suddenly at the deep suture instead of sloping evenly to it, the lateral 

 processes of the neck-lobe are oblique instead of horizontal, the eye seems larger 

 and bordered by tubercles, the median lobes come much nearer the neck, and the 

 inner points of the cheeks are attenuated instead of blunt. But though clearly 

 distinct, the two species are analogous, and it is interesting to note that Lichas 

 Haueri is the only species which Barrande describes from his zone F, which is 

 regarded by Prof. Hughes, Mr. Roberts, Mr. Marr, and others as belonging to the 

 Devonian epoch. No part of either the body or tail is known. 



Lichas granulosus, F. A. Romer, 2 belongs to the same group, but in it the 

 glabella is much larger and more elevated, the cheeks smaller, and the head much 

 less transverse. L. meridionalis, Freeh, 3 appears, as far as can be judged from 

 the description, to have a shorter glabella, more angulated profile, and smaller side- 

 lobes ; these Languedoc specimens, however, seem to have been very fragmentary, 

 and no figure is given by the author. 



Some American species seem to approach Lichas Devonianus more nearly than 

 the Continental. Lichas (Arges) contusus, Hall, 4 agrees with it in the shape 

 of its frontal lobe, but it is a flatter and much less transverse species and the fixed 

 cheeks are situate more in the rear of the side-lobes of the glabella. In L. hylseus, 



3 1852, Barr., ' Syst. Sil.,' vol. i, p. 604, pi. xxviii, figs. 38—44, Et. F. 



2 1852, F. A. Bom., « Beitr.,' pt. 2, p, 85, pi. xiii, fig. 3, and pt. iii, p. 24, pi. v, figs. 8, 9. 



3 1887, " Falseoz. Bildungen von Cabrieres," ' Zeitsch. der deutsch. geol. Gresell.,' Jahrg. 1887, 

 p. 465. 



4 1888, ' Fal. N. Y.,' vol. vii, p. 83, pi. xix b, figs. 3-6. 



