7IO CRETACEOUS PALEONTOLOGY. 



of which they become obsolete; on all the upper whorls the folds 

 extend from suture to suture, but on the last one they are marked- 

 only on the upper or larger parts ; outer lip expanded, forming- a 

 broad, wing-like extension which is prolonged below along the 

 moderately long rostral beak, and above is extended intO' an ob- 

 tusely pointed hook-like process from its outer upper border. This 

 feature I have seen entire only on the type specimen, though 

 several are before me which show the expansion of the lip. Na 

 keel-like ridge marks the back O'f the lip, as in most of the species 

 of this group from the Cretaceous beds oi the Upper Missouri 

 region." (Whitfield.,) 



Remarks. — ^This species is one of the abundant gastropods in 

 the Merchantville clay, and it only occurs commonly else- 

 where, SO' far as it has. been observed, at one locality in the 

 Wenonah sand. Whitfield illustrates two specimens, one from 

 Holmdel and one from Haddonfield. The first of these must be 

 from the Navesink marl, and is, perhaps, a small individual of 

 A. pennata, and the last is from the Woodbury clay and is cor- 

 rectly identified. The type specimens used by Gabb are certainly 

 from the Merchantville clay-marl near Burlington. The species 

 may be distinguished from all other members of the genus in 

 the New Jersey faunas by its smaller size, rarely attaining a 

 height of over 25 mm. It is essentially a miniature form of 

 A. pennata, and, perhaps, should not be considered as distinct 

 from that species, and there seems to be no^ basis whatever for 

 referring the species to a genus different from that to- which 

 other New Jersey shells of this type are referred, as has been 

 done by Whitfield. The specimens from the Wenonah sand 

 near Crawfords Corner seem to be essentially identical with 

 the Merchantville specimens in form and size ; a single individual 

 preserves the expanded outer lip, but it is smaller than the lip 

 of full grown Merchantville specimens, and . lacks the outer 

 posterior angle. This difference may be due, however, to the 

 immature condition of the lip on the specimen, since the growth 

 lines on some Merchantville specimens indicate that the lip has 

 passed through a similar form before reaching its mature fonn. 



Formation and locality. — Merchantville clay-marl, near Mata- 



