MARYLAND GEOLOGICAL SURVEY 601 



Radula reticulata Whitfleld, 1885, Mon. U. S. Geol. Survey, vol. ix, p. 63, 



pi. ix, figs. 8, 9. (Synonymy excluded.) 

 Lima reticulata Weller, 1907, Geol. Survey of New Jersey, Pal., vol. iv, p. 



492, pi. liv, figs. 3, 4. 



Description. "L. testa ovata, obliqua, inflata, tenui, longitudinaliter 

 sulcata, sulcis reticulatis, numerosis. Habitat, Nov. Jersey." Forbes, 

 1845. 



" Shell small, moderately oblique, strongly ovate, and inflated. Hinge 

 short; beaks proportionally strong, and projecting beyond the cardinal 

 line. Valves nearly equal ; anterior margin straight, and not at all gaping ; 

 auriculations small but distinct, rectangular or very slightly pointed at 

 their outer angles. Surface radiately ribbed, those of the anterior and 

 posterior slopes faintly marked or obsolete, ribs (about thirty) distinct, 

 with live or more indistinct on each side; subangular on the middle of the 

 valves and rounded toward the sides, crenulate or subspinose on the larger 

 specimens when well preserved, but often appearing nearly smooth. Entire 

 surface marked by concentric lines which give a roughened surface when 

 perfect, giving the reticulated character indicated by the specific name. 

 The shells are all small, seldom exceeding three-fourths of an inch in 

 length, and are very fragile. The right valve apears to be a little less 

 ventricose and the beak shorter than the left in all the specimens which I 

 have seen where the two are united." Whitfield, 1885. 



There is apparently a large amount of variation in this small species, 

 and, as the type is not in this country, it is difficult to determine its proper 

 limits. In Maryland the forms referred to this group are all young and of 

 rather doubtful affinities, so that they throw no light upon the characters 

 of the race. Radula denticulicosta Gabb is probably distinct if Gabb was 

 correct in his observation that " at both the anterior and posterior sides 

 the ribs disappear for about one-sixth the width of the shell." 



Occurrence. MONMOUTH FORMATION. Brightseat and McNeys Cor- 

 ners, Prince George's County. 



Collections. Maryland Geological Survey, New Jersey Geological Sur- 

 vey, U. S. National Museum. 



