228 
ANTI ARCH A. 
Bothriolepis obesa, Traquair. 
1888. Bothriolepis obesus, R. H. Traquair, Geol. Mag. [3] vol. v. p. 510. 
Type. Detached plates of trunk; Edinburgh Museum. 
An imperfectly known species, of large size. Anterior median 
dorsal plate carinate; posterior dorso-lateral relatively short and 
deep ; posterior ventro-lateral with relatively high ascending lamina. 
Ornamentation consisting of large, partially fused tubercles. 
Form. Loc. Upper Old Red Sandstone: Rule Water, near 
Jedburgh. 
Rot represented in the Collection. 
Bothriolepis canadensis, Whiteaves. 
1880. Pterichthys (Bothriolepis ) canadensis, J. F. Wkiteaves, Amer. 
Journ. Sci. [3] vol. xx. p. 135, and Canadian Naturalist, n. s. 
vol. x. pp. 26, 28. 
1885. Bothriolepis canadensis, E. D. Cope, Amer. Nat. vol. xix. p. 290, 
woodc. 
1887. Pterichthys ( Bothriolepis ) canadensis, J. F. Whiteaves, Trans. 
Roy. Soc. Canada, vol. iv. sect. iv. p. 101, pis. vi.-ix. 
1888. Bothriolepis canadensis, R. H. Traquair, Geol. Mag. [3] vol. v. 
p. 509, and Ann. Mag. Nat. Hist. [6] vol. ii. p. 496, pi. xviii. 
fig. 6. 
1889. Bothriolepis canadensis, J. F. Whiteaves, Trans. Roy. Soc. 
Canada, vol. vi. sect. iv. p. 91. 
Type. Nearly complete individual; Geol. Survey of Canada, 
Ottawa. 
A species of moderate size, the head and trunk attaining a length 
of about 0T7. Head much broader than long, about one half as 
long as the dorsal carapace of the trunk; trunk broadly ovate, the 
sides overhanging the narrowly ovate ventral surface. Proximal 
segment of pectoral appendages broad, but elongated ; distal segment 
relatively slender, only slightly ornamented, two thirds as long 
as the proximal segment; outer and inner margins coarsely ser¬ 
rated. Anterior median dorsal plate as broad as long, more or less 
keeled in its posterior two thirds ; posterior median dorsal plate 
longitudinally keeled, the keel rising to a slight eminence near the 
posterior margin. Ornament consisting of fine rounded tubercles 
fused into nodose, vermiculating ridges ; those near the edges of the 
dorsal plates often directed mainly at right angles to the margins. 
Form. Loc. Upper Devonian : Scaumenac Bay, Province of 
Quebec, Canada. 
