STANTON I THE MARINE CRETACEOUS INVERTEBRATES. 35 



30 on last whorl); aperture not perfectly preserved, but evidently entire 

 and rounded below, with outer lip thickened and reflected, so as to form 

 a smooth band two millimeters wide externally, and columella with two 

 strong folds. 



Height, 10 mm.; greatest breadth, 9 mm.; height of aperture, 7.5 mm.; 

 breadth of aperture, 4 mm. 



The type specimen is very well preserved, but the outer lip is broken, 

 so that the form of the upper part of the aperture cannot be determined 

 accurately, and it is not certain whether the inside of the outer lip is 

 crenulated. There are two other imperfect specimens in the collection. 

 Behrendsen 1 reports imperfectly preserved specimens of a Cinulia from the 

 Neocomian at Arroyo Triuguico near its junction with the Rio Neuquen, 

 but it is not possible to determine from his descriptive note whether they 

 are identical with the present form or not. 



Locality and position. From the Ammonite (Belgrano) beds, ten miles 

 east of Lake Pueyrrydon. 



CEPHALOPODA. 



Genus HATCHERICERAS gen. nov. 



Shells attaining a large size, compressed, involute (the umbilicus usually 

 forming about one-fifth of the diameter of the shell), with rounded venter 

 and very slightly convex sides, which in the adult may be nearly or quite 

 smooth, but in the young are marked by low, curved, branching ribs that 

 sometimes tend to form tubercles around the umbilical margin and on 

 either side of the venter. In the early stages the ribs cross the venter but 

 later they are interrupted more or less distinctly there before they disappear 

 from the flanks. The relatively narrow umbilicus is funnel-shaped, its 

 slopes becoming smooth and somewhat concave in the later stages but 

 the inner whorls have rounded margins on which the ends of the ribs are 

 seen within the umbilicus. 



Lobes and saddles of the suture not very complex, nor deeply incised, 

 and characterized generally by their great breadth. The ventral lobe with 



l Zeitschr. deutsche geol. Gescllschaft, Bd. 44, 1892, p. 18. 



