114 Morgan Expeditions. 



The first distinguishing feature of this species lies in the 

 great prominence of the test, none of the forms, with which 

 we have compared it, approaching it at all in convexity. 

 This difference of character is supplemented by many others. 

 From Dalmania Boolhii, of the Hamilton group of New 

 York, the only abundant form known in beds corresponding 

 most nearly in age to the Erere Devonian, it differs, among 

 other features, in the greater proportionate length of the 

 middle of the head, in the more gradual backward nar- 

 rowing of the glabella, and in the greater length of the 

 frontal lobe, which is generally more angular in front in 

 the latter form. 



This beautiful species occurs somewhat abundantly in the 

 Devonian sandstone at Erere, associated with Spirifera Ped- 

 roana, etc. The specific name is given in allusion to a 

 mythical personage, after whom the Serra of Paituna in 

 the vicinity received its name. 



Genus HOM ALONOTUS, Kcenig. 

 Homalonotus Oiara, sp. now 



There was obtained from the Devonian sandstone at Erere, 

 a single fragment of the head of a large trilobite, which be- 

 longs to this genus. It is very distinct from any other form 

 yet known, but too imperfect to admit of proper descrip- 

 tion. It differs from Homalonotus Delcayi, Van., appar- 

 ently, in the fact that the margins of the glabella are more 

 concave than in the latter form, and the eyes are placed 

 farther forward. We have ventured to rank it as a new 

 species, naming it after the Tupi water maiden. Associated 

 with the last species above described, Dalmania Paituna. 



GASTEROPODA. 



Genus PLEUEOTOMARIA, Defrance. 

 Pleurotomaria Rochana, sp. nov. 



Shell quite small; outline, as seen in front and hind view, a rhomboid, 

 of which two opposing sides are about twice the length of the other two 



