208 
ANTIARCHA. 
\ 
minor , L. Agassiz, Poiss. Eoss. vol. i. (1844), p. xxxiii 
(name only).—Devonian ; Riga and St. Petersburg. Upper 
Old Red Sandstone ; Elgin. [Original of Agassiz, pi. xxx. 
fig. 11, considered as probably referable to Asterolepis 
coneatenata by E. von Eichwald, Leth. Eossica, vol. i. 
(1860), p. 1510.] 
Asterolepis speciosa , L. Agassiz, op. cit. (1845), pp. 93, 146, 
pi. xxx. fig. 10, pi. xxx. a. fig. 4.—Devonian; Yoroneje, 
Russia. 
Asterolepis wenJcenbachii, C. Koch, Yerbandl. naturh. Yerein., 
Bonn, vol. xxix. (1872), Correspond, p. 85 (name only). 
—Devonian ; Eifel. 
Head and trunk broad, but much elevated, the scutes ornamented 
with tubercles; tail covered with rounded or hexagonal scales, 
slightly imbricating. Lateral sensory canals on the upper aspect of 
the head united by an anterior transverse commissure crossing the 
premedian plate, and a posterior one directly crossing the median 
occipital; anterior median dorsal plate overlapping the anterior 
dorso-lateral, overlapped by the posterior dorso-lateral. Pectoral 
appendages shorter than the armoured trunk, segmented into a 
distal and proximal portion; marginal scutes of proximal portion 
separated above and below by a median “ anconeal ” element; 
marginal and central scutes of distal portion few. A single small 
median dorsal fin, with large anterior fulcra! scales, but apparently 
no fin-rays. 
The exoskeleton of this genus is now tolerably well known, 
owing especially to the researches of Miller, Pander, and Traquair; 
and the accompanying restorations (fig. 33, A, B, C) are those of the 
last-named author. Eig. A represents the dorsal aspect, and fig. B 
the ventral aspect, while fig. C is a side view. The exposed margins 
of the plates of the trunk are shown by thickened lines, while the 
amount and direction of their overlap are indicated by the thin 
lines. Sensory canals, both upon the head and trunk, are marked 
by double dotted lines. We would only add that the large inferior 
expansion of the caudal fin is omitted in the third figure (compare 
PI. YI. fig. 3, ; and for the details of the hard parts in the 
orbital opening, reference must be made to some of the specimens 
described below, notably the original of PI. Y. fig. 2. 
The cranial shield is small compared with the armour of the 
