144 ENTOMOSTOMATA. 



genera, by the notch or slit in the anterior edge. In the genus 

 Rimula, Defr. fig. 243, this slit is near the apex, and does not 

 reach the margin. Recent species occur in all climates, but are 

 not numerous. Fossil species are still more rare, occurring in 

 the Calc-grossier, Crag and Oolite. E. fissurata, fig. 241. 



ENA. Leach. A sub-genus of Bulinus. B. Lackhamensis. Mont. 



ENDOSIPHONITES. A genus composed of Ammonites, having 

 the siphon close to the body whorl, fig. 476. 



ENDOTOMA. Rafinesque. A genus of microscopic Foraminifera. 



ENROULEES. Lam. See Convolute. 



ENSATELLA. Sw. A genus consisting of Solen ensis, Auct. 

 fig. 60, and other species similarly curved. Genus Ensis, Schum. 



ENSIS. Schum. Solen ensis, Auct. and similar species. 



ENTALIS. Defr. Dentalium duplicatum, Bl. Pharetrium, 

 Konig. This genus is described as a small tube, within a larger 

 one, the smaller extremity of the inner tube projecting beyond 

 that of the outer one. Deshayes, who describes this genus, ex- 

 presses a conviction that the soft parts of the animal must be 

 entirely different from those of the animal of Dentalium. The 

 genus Pharetrium, as described by Konig in his "IconesFos- 

 silium Sectiles," is evidently identical with Entalis. It is placed 

 by him in the family of Pteropoda, but being a fossil shell, there 

 is some difficulty in finding its place in the system. See plates, 

 fig. 3. 



ENTELLITES. Fischer. A genus composed of species of Tere- 

 bratula, Spirifer, and Productus, Auct. having the hinge 

 large and the umbones short. Orthis ? Dalman. 



ENTIRE. (Integra.) Not interrupted, not emarginated. The peri- 

 treme of a univalve shell is said to be entire when not interrupted 

 by canals or by the body whorl. Ex. Cyclostoma, fig. 304. The 

 palleal impression is entire, when continued without interrup- 

 tion, or without a sinus. 



ENTOMOSTOMATA. Bl. The second family of the order Siphoni- 

 branchiata, Bl. The shells of this family are described as dif- 

 fering but little from those contained in the family of Siphono- 



