16 SYEIAN MOLLUSCAN FOSSILS. 



Amauropsis. As the application of the former name seems not 3'et to 

 be definitely settled, I have for the present ibllowed Zittel in assigning 

 hulhiformis (and with it the other two species) to Aiitauropsis, though it 

 may be questioned whether the name is justly applicable to any one of 

 the three. 



Besides the resemblance of the three species in general form, and in 

 characters of mouth and sjnre, their striking similarity in the region of the 

 suture is to be observed. In the several s])ecies each volution tei-minates 

 behind in a more or less truncately flattened area, Ijounded within, next to 

 the suture, by a tliin and slightly elevated rim, and withoiit, in two of the 

 species, by a distinct, rounded, backward-projecting varix, which, witli the 

 internal rim, accompanies the area to the top of the spire. The space be- 

 tween the rim and the varix constitutes a canal, deep and ilat-floored in Jmlld- 

 formis; less deep and with bottom sloping outward, but sulficientlj^ marked, 

 in the present species ; while in the following one it becomes a slightly con- 

 cave shelf, bounded inside by the small but persistent sutural rim, and exter- 

 nally by the varix, present indeed but reduced to a minimum. In all three 

 species is found tlie same lightly impressed and almost linear suture, the 

 canaliculation being wholly outside the suture proper and distinct from it. 

 Coll. Bird. 



Locaiiti/ awl Poslllon. — Abeili ; from the arenaceous Turonian marl. 



Amauropsis gradata, ^v- "ov. 



Plate I, Hg. .1. 



Testa kdc-ovala ; sjnra clcvatu, jliJi'amidaUi, apice acuto : aufradus sex, a latere 

 am^lanati, postice prope siduram acute angiilati ct late tahdati, spira speciem scalarmn 

 gerente ; anfradus idiimus spira longior, latior qnam longior, ad angiduin latissiinus, 

 prorsiim siihito contraclvs : sutnra linearis margine exili infra circumdata : apcrlura 

 sublunata, antice product a et incurvaia, postice hiangntida ; lahruni simplex; columella 

 excavata, rimam nmhilicalcm ex/dtjens. 



Shell broadly ovate ; spire elevated, pyramidal, having the apex acute : 

 whorls six, flattened on the sides, behind near the suture shai'ply angled and 

 widely tabulate, the spire showing the form of a winding staircase ; last 

 whorl longer than the spire, wider than long, broadest at the angle and 

 thence rapidly diminishing forward : suture linear, bordered by a narrow 

 margin slightly raised on each whorl : aperture sublunate, in front produced 



