118 Morgan Expeditions. 



Although a number of specimens of this species of Bellero- 

 phon were obtained from Erere, 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. Couiinhoanus is very closely allied to B. 

 trilobatus of Sow., Devonian of Europe, more especially to 

 the variety tumidus, 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 Erere, Prov. of Para, 

 Brazil ; associated with JSJuculites 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 ,nm ; width of the body volution 

 near the aperture, about 5 mm . 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. 



