264 THK icK a(;k in Canada. 



lialiinuH hiilauoidt's. 



Fossil — I'ortliuid, Miiiiif. Not yut in Canada. 

 EiipntfitrKs Ji( niliarihis / Kiihiicius. 



Fossil — Rivirredii-fiOiiii. A siiiiiU specimen in a Turritilld may l)c 

 the young of tliis common species. 



IfijdH ro(ir'-t(i/ti. Leach. 



Fossil — Rivirre-du-Loup. A few claws only found, Imt evidently 

 of this common (>ulf of St. Lawrence species. 



Estherin Dawsoni. Packard. 



Fossil — (Jreen's Creek, Ottawa. 



A new species found in tlie nodules containing fishes, &c., and 

 described hy Packard as follows* : — 



This Kstlieria is entirely unlike any northern American or Kuropean 

 species, ditl'ering decidedly from Esthcrid morsel or E. addirdli and 

 E, darkii. It rather approaches E, jonem from Cuba in tlie form of 

 the .shell and style of marking of the valves. It does not resemble 

 closely any of the fossil forms figured in .Jones' Monograph of Fossil 

 Estheriie. Tiie markings, however, present some resemblances to 

 E. middendorfii Jones, but differs in the want of anastomosing cross 

 wrinkles between the ridges. 



One valve and portions of others were preserved ; ))ut none of them 

 show the l)eaks (umbones), though the form of the remainder of the 

 shell indicates that they were situated nearer the middle of the valve 

 than usual — i.e., between the middle and the anterior third of the shell. 

 The shell is <leep, probably more so than in E.jo/U'sii, though the valves 

 have evidently been flattened and somewhat distorted by pressure, but 

 apparently the head-end was more truncated than in E. jonesii, as the 

 edge of the shell and the parallel lines (or ridges) of growth along the 

 head-end are, below, bent at right angles to the lower edge of the shell. 

 The raised lines of growth are very numerous and near together ; they 

 are of nearly the same distance apart above, near the beaks, as on the 

 lower edge. The very numerous li»'?s of growth are thrown up into 

 high sharp ridges, the edges of whieh are often rough, finely granu- 

 lated, and often the valleys between are rugose on the surface. In one 

 or two places a row of papillie for the insertion of spinules may be seen 

 where the shell has been well preserved, and between many of the lines 

 of growth there are irregular superficial ridges. Length, 10 mm, ; 

 depth, 7.5 mm. 



* American Naturalist, June, 1881. 



