510 Dr. R. H. Traquair— Old Red Sandstone Fishes. 
In Bothriolepis the head plates show considerable differences of 
shape from those in Pterichthys and Asterolepis, the most important 
being the case of the postmedian, which does not extend outwards 
on each side to join the lateral plate, but, antero-posteriorly hemi- 
elliptical in contour, is received in a deep rounded notch in the 
median occipital. The grooves of the lateral line system are dif- 
ferently arranged on the head, and on the anterior median dorsal 
a prominent groove is seen in the form of an inverted V with the 
apex near the centre of the plate. The carapace is rather flattened 
above, and there is a longitudinal dorso-lateral as well as a ventro- 
lateral sharp inflexion or carina, while the arms are particularly 
long, sometimes extending beyond the posterior extremity of the 
carapace. It is odd that no trace of a scaly tail should ever have been 
discovered in Bothriolepis in spite of the perfection of numerous 
specimens in every other respect, but this by no means proves that the 
tail itself was absent, only that it had no preservable hard parts. 
To Bothriolepis belong ‘“ Pterichthys” major, Ag., from the Upper 
Old Red of Scat Craig, Heads of Ayr, Siccar Point, etc.; “ Pam- 
phractus” hydrophilus, Ag., from Dura Den; “ Pterichthys” macro- 
cephalus, Egert., from Farlow, and I shall here indicate what I 
consider to be two additional British species. 
Bothriolepis giganteus, n.sp. Traq. (= Bothriolepis ornatus, Ag. 
pars, non Hichwald).—Of large size; anterior median dorsal plate 
gently convex, not carinate, surface of plates covered by rather 
coarse tubercles more or less confluent into vermicularly contorted 
sometimes reticulated ridges, and frequently displaying stellate bases. 
Fragments of impressions of plates of this species were figured by 
Agassiz as belonging to B. ornatus, Hich. (Old Red, tab. 29, figs. 3, 
4,5), but the anterior median dorsal plate is broader in shape than 
that figured by Eichwald, and the sculpture is also different. Upper 
Old Red, Alves, near Elgin. I am greatly indebted to the Rev. Dr. 
Gordon of Birnie and to the Directors of the Elgin Museum for the 
opportunity of studying the remains of this magnificent species, of 
which I intend soon to give a detailed description in another place. 
Bothriolepis obesus, n.sp. Trag.—Of this I have only seen the 
anterior median dorsal plate, posterior dorso-lateral, and the anterior 
and posterior ventro-laterals, the specimens being contained in the 
collections of the Geological Survey of Scotland, and of the Museum 
of Science and Art, Edinburgh. The dorsal plate is carinated along 
the middle line, the posterior dorso-lateral is peculiarly short and 
deep, the posterior ventro-lateral is remarkable for the great height 
of its ascending lamina, the contour of these plates indicating a 
carapace of a proportionally short and “thick-set”’ aspect. Surface 
coarsely tuberculated. This is also a large species, and from the Upper 
Old Red of Rule Water, near Jedburgh. All the British species of 
Bothriolepis are from the Upper Old Red Sandstone, and comprise 
the largest as well as nearly the smallest of the known forms of 
Asterolepide. 
Microbrachius Dickii, n.gen. Traq. (= Pterichthys Dickii, C. W. 
Peach, name only, British Assoc. Rep. 1867, Trans. of Sections 
