Morgan Expeditions. 118 
Although a number of specimens of this species of Bellero- 
phon were obtained from Ereré, the aperture is not preserved 
in any of them, and the umbilical openings, if such existed, 
are covered up by the rock in every case. The specimens 
are all of internal moulds and the surface markings are not 
retained. B. Coutinhoanus is very closely allied to B. 
trilobatus of Sow., Devonian of Europe, more especially to 
the variety ¢umidus, from which, however, it differs in hav- 
ing the dorsal lobe broader, less prominent, and more flat- 
tened along the top, with its margins more distinctly defined. 
From the Devonian sandstone of Ereré, Prov. of Para, 
Brazil; associated with Muculites Nyssa, etc. 
Respectfully dedicated to Dr. Silva de Coutinho, Rio de 
Janeiro, Brazil. 
Bellerophon Gilletianus, sp. nov. 
Shell very small, laterally compressed, somewhat lenticular in form and 
sub-circular in outline; umbilical openings of medium size, deep. The 
outer volution commences very small, somewhat compressed and more or 
less angular on the median dorsal line, and increases rapidly in prominence 
but quite gradually in width, becoming more and more strongly angular 
toward the aperture, where it is but slightly expanded. The summit of 
the mesial prominence is often well rounded, but sometimes acute, while 
on each side is generally a very shallow accompanying groove, growing 
more pronounced toward the aperture, and which gives to the shell near 
the mouth a somewhat trilobed appearance. 
The surface of the shell is marked by numerous, very fine, rounded, 
thread-like, concentric raised lines, which arch very strongly backward 
from the umbilici to the median dorsal line, where the corresponding 
ones on each side unite in a curve. Of the largest specimen obtained, 
the greatest diameter, which is from the outer margin of the aperture to 
the opposite side of the shell, is about 10 ™™; width of the body volution 
near the aperture, about 5™™, Most of the specimens, however, are 
much smaller than this. 
B. rotiformis of De Kon., Europe, resembles the species 
just described in size and general appearance, but it is more 
lenticular in shape and the whorls increase more rapidly in 
size. The umbilical openings are also smaller and the slope 
toward them is much less abrupt. 
