102 AMERICAN JOURNAL 



terized by the funnel-shaped dorsal siphuncle, has not yet 

 been found below the Eocene. Mr. Gabb does not describe 

 the siphuncle or its position in his shell, and I have been 

 guided only by the angles of the septa not being contiguous 

 and its geological position in the cretaceous formation. If 

 Mr. Gabb will compare the specimens from Division A with 

 those in Division B, and note the differences, if any, especially 

 in the siphon, it will be important both in a stratigraphical 

 and conchological point of view. My attention to this subject 

 has \ery recently been called by the account of JV. Parkimoni, 

 in Edwards' Monograph of the Eocene Cephalopoda, and when 

 I first saw the figure of Aturia Matthew soni I had no doubt of 

 its being an Aturia. 



CIMOMIA, Conrad. 



Nautiloid ; septa sinuous, double- waved, or sigmoid, nume- 

 rous ; siphon small, central. 



Nautilus Burtini, Galeotti. — Lower Eocene. 



I do not think any of the cretaceous forms are certainly of 

 this genus. 



APORRHAID^E. 



ANCHURA, Conrad. 



Description.— Genus unknown in the Tertiary. It has a 

 prolonged straight labrum, which either has one long ensiform 

 curve or is biangulated, abrupt, and broad on the outer mar- 

 gin ; the latter being the typical form and the former the 

 subgenus Drepanochilus, Meek. The cretaceous species of 

 France, as figured by D'Orbigny, are 1 Bost. Dupiniana, 2 R. 

 Robinaldina, 3 R. alpina, 4 R. asteriana, 5 R. carinata, 6 R. 

 calcarata, 7 R. tricostata, 8 R. carinella, 9 R. Parkinsoni, 10 

 R. simplex, 11 R. ornata, 12 R. Requieniana. Of these No. 6, 

 7, 10, 11, 12 represent the subgenus Drepanochilus, Meek. 



TELLINID^E. 



CYPRIMERIA, Conrad. 



This genus is limited to the Chalk Period, and embraces the 

 following species : C. Texana (Arcopagia Texana, Eoemer), G. 

 densata {Arcopagia densata, Conrad), G. excavata (Gytherea ex- 

 cavata, Morton), and G. Peruviana, Conrad. European species : 

 G. concentriea (Girce concenirica, Zittel), G. cretacea (Dosinia 

 eretacea, Zittel), G. primseva (Cyclina primseva, Zittel), G. discus 

 (Lucina discus, Matheron), Arcopagia numismalis, D'Orbigny, 

 A. rotundata, D'Orbigny. I should have proposed another 

 name had I properly understood the family characters of this 

 shell when I published it. 



