NATURAL SCIENCES OP PHILADELPHIA. 971 



This genus has the same relation to Defrancia that Metulella 

 bears to Metula. The inner lip of G. dentifera, the only known 

 species, is thickened, and is crossed by a number of prominences, 

 intermediate in character between teeth and transverse folds. At 

 the same time, they are wholly unlike the one fold of B or soma, or 

 the two or three of Cordiera. A better comparison would be with 

 the teeth of Cyprsea. 



BUCCINIDiE. 

 Ectracheliza, Gabb, pi. 9. fig. 2. 



Shell acuminately oblong, spire elevated (always truncated in the 

 only species known). Surface compressed near the suture. Inner 

 lip encrusted ; columella sinuous, short ; outer lip produced in 

 advance. This genus seems to be allied in many of its characters 

 to Cominella and Truncaria. Like them, it is compressed ad- 

 joining the suture. It shows no trace of umbilicus, as seen in 

 most of the Buccinidre, but its most distinctive character is in 

 its obliquely sub-truncated columalla, which does not reach to 

 the anterior end of the shell. It differs from Truncaria in having 

 no fold on the columella and in the outer lip not being emarginate 

 posteriorly. In E. truncata, the apex is truncated at. all ages, 

 shells of less than half an inch long having lost several of their 

 apical whorls, and it is rare to find more than two entire volutions 

 in any specimen. 



OLIVID.ffi. 

 Plochel^a, Gabb, pi. 11, fig. 5. 



Shell olive shaped, suture nearly obsolete, as in Ancillaria ; 

 aperture linear, deeply and obliquely notched at the base, as in 

 Dibaphus. Outer lip thickened internally, in the middle ; inner 

 lip incrusted and having several transverse folds, of which the 

 upper are the smallest ; columnella strongly recurved at the base. 



From its form and general appearance, I am inclined to consider 

 this genus as belonging to the Olividae, although its details of 

 character are strikingly like that of Dibaphus. It seems to form, 

 in a manner, a connecting link between the true Olives and the ' 

 genus Monoptygma Lea (not of Adams, Sowerly, etc.) The 

 folds are placed in a reverse order to those of Milra. 



I have before me specimens of Dibaphus edentulus and Mauritia 

 Barclayi, the typical species of their respective genera. There is 

 no possible room for doubt that D. edentulus is at least sometimes 



