328 . nSSURELLID^, 



In 20 to 100 fathoms water. Fossil, in the glacial formations of 

 North Britain. B. Noachina, Linn. (Ixxxiv, 33). 



CRANOPSis, Adams. Fissure about the middle of the anterior 

 side ; an internal vaulted chamber over the foramen, resembling 

 that of Puncturella, Cr. pelex^ Adams (Ixxxiv, 34, 35), from 

 the China seas, is the tj^pe, and one or two additional species 

 have been since described. 



SEMPERiA, Crosse. (Named after M. 0. Semper, of Altona.) 

 Shell conical, apex posteriorly recurved, anteriorly fissured ; the 

 fissure is marginal in the j^oung shell, but in the adult the margins 

 grow around it so that it becomes subdorsal, or separated from 

 the margin externally, though connected with it internally by a 

 channel. Embraces at diiferent growth-stages characters of 

 Rimula, Emarginula, Clypidina. 2 sp. Madeira. Fossil ; Paris 

 basin. S. elegans, Crosse (Ixxxiv, 36). 



Emarginula, Lam. 



Etym. — Diminutive of emarginata, notched. 



Syn. — Nesta, H. Adams. 



Distr. — 40 sp. West Indies, Britain, Norway, Philippines, 

 Australia. Bange from low-water to 90 fathoms. Fossil, 40 sp. 

 Carboniferous — . E.fissura (Ixxxiv, 3*7). 



Shell oval, conical, elevated, with the apex recurved ; surface 

 cancellated ; anterior margin notched. Muscular impression 

 with recurved points. The nucleus (or shell of the fry) is spiral, 

 and resembles Scissurella. The anterior slit is very variable in 

 extent. The animal of Emarginula (and also of Puncturella) has 

 an isolated cirrus on the back of the foot, perhaps representing 

 the operculigerous lobe. — Forbes. Lingual dentition (xii, 50), 

 median teeth subquadrate ; laterals four, oblong, imbricated ; 

 uncini about 60, the first large and thick, with a lobed hook, the 

 rest linear, with serrulated hooks. — Loven. 



SUBEMARGINULA, BMnv. (Hcmitoma, Swain. Siphonella, Issel. 

 Montfortia, Recluz.) Anterior margin with a slight channel and 

 a canal-like prolongation of it proceeding towards the apex, on 

 the inside face of the shell. E. octoradiata, Sowb. (Ixxxiv, 3T). 



zeidora, Adams. Shell like Emarginula, with the margin of 

 the aperture crenulated and anteriorly deeply fissured, but there 

 is posteriorly an internal, fiat, semilunar septum present, which 

 distinguishes this subgenus from .any other Fissurellidse. E. 

 reticulata, A. Ad. (Ixxxiv, 39, 40). 



Pbslongchampsia, M'Coy, 1850. (Dedicated to Dr. Eudes 

 Deslongchamps, the renowned French palseontologist.) Shell 

 patelliform, apex acute, excentric ; with a wide longitudinal 

 anterior sulcus, produced into a rounded lobe. Fossil, 3 sp. 

 Lower Oolite; England, Normandy, Galicia. D. Eugenei, M'Coy 

 (Ixxxiv, 41). 



