NUCULA (CUCULLELLA ?) PAL^ESTINA. 55 



Nucula (Cucullella?) Palsestina, sp. oov. 



Plato VI. figs. 5 a-i. 



Testa parva, subcylindrata, duplo longior qtiam alitor, maxime inmquUatera ei 

 rrn/ricom, crassitudo altitudiui fn-c luhcqmns ; antice attenuata submucronata ; extre- 

 mitas postica paulo compressa, acuta; margo dorsi antice insinuata, postice paululatim 

 declivis ; margo ventris antice subsinuata, postice cequaliter arcuata: umbones humiles 

 inconspicui, antrorsum inclinati: lunula supeme angulo acuto apicum definita, inferne 

 ri.v limitata: superficies striis concentricis tenuibus confertissimis notata: cardo mulr 

 tidenticulatus ; linea cardinaKs obtusangula. 



Shell small, subcylindrical, twice as long as high, exceedingly inequilat- 

 eral and ventricose, the thickness almost equalling the height ; attenuate 

 and submucronate in front; hinder extremity a little compressed, sharp; 

 dorsal margin sinuated before, behind very gradually sloping; ventral margin 

 subsinuate in front, posteriorly regularly arcuated : umbones low, inconspicu- 

 ous, inclined forward: lunule defined above by the acute angle formed by the 

 beaks, below scarcely limited: surface marked by delicate concentric stria?, 

 very closely set; hinge multidenticulate ; hinge-line obtusely angled. 



Thirty-three specimens, all with test entire. Length, 13 to 15^ mm.; 

 height, 7^ to 8J mm. ; thickness, 7 to 85 mm. 



Of the -whole number only a single specimen allowed the test to be 

 removed, leaving the cast with all fts markings distinct, except the anterior 

 slope of the hinge line, which is partially obscured, but evidently toothed. 

 The muscular impressions are shown to be deep and somewhat angular, the 

 pallial line simple and rather distant from the ventral margin. The anterior 

 boundary of the umbones is more conspicuously angular and prolonged in 

 the cast than in specimens covered by the test. A little behind the beaks 

 of the cast a groove runs from the dorsal margin almost vertically downward 

 (slightly backward) about 2 mm. It is divided lengthwise into two grooves 

 by a ridge along its middle. In Cuadlella M'Coy,* according to the diagnosis, 

 ••a strong internal septum [clavicle] extends from before the beaks to the 

 posterior margin of the anterior adductor, forming a deep slit in the casts." 

 Our cast indicates the existence of a channelled septum (within the test) 



Zittel (Handbucb der Palseontologie, I. Band, 2. tfbtheilung, p. 53) regards Cucullella M'Coy (Annals 

 and Magazine of Natural Eistorj [2], VII, p. 50, 1851) and Cleidophorus Hall (Palaeontology of New York, 

 I, p. 300, 1847) as identical. Both arc palaeozoic. 



