246 SMITH. [Vol. XVI. 



K. A. von ZitteP has separated ScJdoenbacJiia from the 

 Amaltheidae, and placed it in a family of its own, the Priono- 

 tropidae ; which change is quite proper, for ScJiloenbachia does 

 not go through in its adolescent period any stages correspond- 

 ing either to Amaltkeus or Oxynoticeras. Zittel regards the 

 Prio7iotropidae as an offshoot of the Avialtheidae, and these in 

 turn from the Pjvlecanitidae ; but neither Schloenbachia nor the 

 AmaltJieidae go through larval stages corresponding to this 

 Paleozoic group, but rather to the GlypJiioceratidae . 



Schloenbachia oregonensis Anderson ms., Pis. A-E. 



Schloetibachia sp. indet., aff. S. chicoensis Trask ; J. P, Smith, Joiirn. GeoL, 



PI. A, Figs. 1-7, vol. V, No. 5, p. 521, 1897. 

 Schloenbachia sp. indet., J. P. Smith, Chapter IX in Jordan's " Footnotes 



to Evolution," PI. C, Figs. i-ii. 



The adult is narrow, discoidal, high-whorled, with wide, shal- 

 low umbilicus, and almost parallel sides. The whorls embrace 

 about two-fifths of the preceding. The surface is ornamented 

 with strong ribs that branch in groups of two from strong knots 

 on the umbilical shoulders, bend forward and form smaller 

 knots on the angular abdominal shoulders, and then turn 

 forward in a sharp angle to the keel. These ribs are exceed- 

 ingly variable, sometimes fine, and sometimes coarse, with 

 transitions from one to the other. Between these bundles of 

 ribs there are from one to two single ribs that do not reach the 

 umbilical shoulders. The keel is rather low, sharp, and slightly 

 notched by the ribs; the sloping space between the keel and 

 the abdominal shoulders has no furrow, although the row of 

 abdominal knots may give that impression. A cross-section of 

 the adult is shown on PI. C, Fig. 7, diameter 22.25 nim., six 

 whorls, on which the increasing relative height and flattening 

 sides of the whorls may be seen. The septa are comparatively 

 simple, and not very digitate ; they show a wide external lobe 

 divided by a short and broad siphonal saddle ; a deep, broad, first 

 lateral lobe ; second lateral lobe about one-half as deep as the 

 first; and a shallow auxiliary lobe. The first lateral saddle is 

 notched rather deeply near the middle, a character that begins 



1 Grundzuge d. Palaeontologie, p. 430, 1895. 



