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tubercles a little longer than those surrounding them, and which cover all the 
surface. The axis of the pygidium is composed, according to McCoy, of seven- 
teen rings, three or four of which are ornamented in the middle with a big 
tubercle, thus producing a distinct longitudinal series. 
Dimensions. — The length of the cephalic shield is two and a half, and 
the breadth three, millimetres. 
Delations and Dlfferenees. — So far there are known only four species 
in this genus, viz., B. Strzelechii, McCoy, B. MeCoyi, Portlock, B. discors, 
McCoy, and B. OuraUcas, de Verneuil. The last differs from the first by its 
great size, and the style of its ornamentation, but the difference between B. 
IfcGoyi, B. discors, and B. Strzelecldi, is not so appreciable. B. Strzelecldi 
differs from the first by the greater relative breadth of its glabella, and from 
the second by the difference in the arrangement of the granulations covering 
its pygidium, and in the spinous points of its border. 
ILonzon and Localities. — McCoy says this species is common in the 
shales of Dunvegan. Mr. Clarke found some specimens in the limestone at 
Eurragood and Glen William. 
Genus — TOMODUS, L. Agassiz. 
Tomodus convexus ? L. Agassiz. 
PI. XX Pig. 11. 
Cochliodus magnus (pars). L. Agassiz, 1838, Eecli. Poiss. Poss., Ill, p. IVI. 
It is difficult to be certain that this single fragment of a fish’s tooth, 
found among numerous specimens of Carboniferous fossils sent me from 
Australia, really belongs to the species named. To guide me in my deter- 
mination I have nothing but the rather curved shape of the tooth, its terminal 
angle of thirty to thirty-five degrees, and the punctures of its surface, 
characters which correspond very well with those of specimens from near 
Glasgow received under this name. I should not have figured this specimen 
had it not belonged to an order of fishes the presence of which had not been 
previously noted in the Carboniferous rocks of Australia. 
Horizon and Localities. — Mr. Clarke found it in a greyish sandstone 
near Tilleghary in the Port Stephens District. Other and better specimens 
should be searched for, so that it can be accurately determined. 
