28 



SHORTER OONTRIBI'TIONS TO GENERAL GEOLOGY, 1921. 



enamel {roni Cahj ptraphorous ami the wliorls will remain 

 intact; strip off the equivalent deposit in Ortliinilax 

 and the shell itself is destroyed. The latter, so far as its 

 structure is concerned, is more nearly like an involute 

 Terehellvm (such as T. sopilum Brander, figured by 

 Zittel) than like the enameled Calyptraphorus or \vinged 

 Ilippochreiws. 



The latter wait until they have attained their majority 

 and then spread their outer lips and lay down their enamel, 

 once for all. In OrOmulax the involution, as in Ovulum, 

 begins before maturity and continues with the growth of 

 the shell without regard to its age or periodical resting 

 stages. In this particular it is clearly distinguishe<l from 

 any other group included in the Stroinhklat, excepting the 

 suHiciently distinct Tirchrl/iim. 



All students appear to agree in referring 

 Orthaulax to the family Strombidae. Guppy '- 

 emphasized its relation to Ro,stdlaria macrop- 

 tera (nippochreiiefi) and- Zittel " refers it to 

 nippochreneK. Dall ^* at hrst considered it a 

 subgenus of Ro.'itdlaria but in later works '■' 

 returned it to generic rank. In the latter prac- 

 tice he is followeil by the second English 

 edition of Zittel's textbook of paleontology 

 (1913) and by recent writers.'" 



Orthaulax inornalus Gabb. 



Plate II. figures 2-(J. 



Oillidiilii.r hionidliis (ialili. Acad. Nal. Sci. Philadelphia 



Proc, \(il. I'l. p. L'72. pi. II, tigs. :',. 1, 1.S72: Am. 



Ptiilos. Soc. Trans., new ser.. vol. l-"), p. 231, 1.S7.3 

 Dall, r. S. Xat. Mus. Bull. 90, p. S(J. pi. 11. lig. 4. V.nr,. 

 Dall (parti. V. S. Nat. Mus. Proc. vol. 'A. p. .'i09. pi 



s.s. lig. it. i!iii;. 

 Maury, Hull. \m. Paleontology, vol. ."i, p. 2S.j. pi. 



47. lig. 11. 11)17. 

 Ortltauliij iiKiriKifii (iuppy. Geol. Soc. l.uudim C,)uart. 



.Tour., vol. 32, p. .520. pi. 28, fig. 8. 187(1. 



In 1873 Ciabl) described Ortlnnilii.i iinir>i<itus 

 as follows: 



Shell Kniadly riiuiideil-fu.sif(irm. 'I'nung sli(41 with the 

 spire a liiilc ;<hiirli>]' ihau the aperture, suture iiujire.ssed. 

 whorls iiiiinerous, nuclear whorls three, the sui)sec|uent 

 ones showing faint traces of occasional thickenings dis- 

 posed like the varices of Tn'inv: surface smooth; anterior 

 end of body whorl marked by a few faint re\'olvitig lines, 

 no posterior canal. Adult shell more distinctly fusiform, 

 the spire covered liy a longitudinally striated incrustation 

 covering the sutures and extending to the extreme apex. 



'- <;uppy, i{. J. I.-., <leol. Soc. London Quart. Jonr., \'oI. :',2, p. .■.:':), 

 1S76. 



'3 Zittel, K. A. von, Uaudliuch der Palaruutologio, vol. 1, pi. 2, p. 

 260: TrairT' lU- palt'ontologic. vol. 2, p. 25S. ISS7; Ti'xtt>ook of paleontology 

 (Eastmun-Zilti'li, vol. I, p. 472, 1900. 



'< WagniT Free Inst. Sci. Trans., vol. 3, p. Iii9, 1S90. 



>5 U. S. N;u. .Mu.s. Hull. ;iO, p. Stj, 191.5; U. S. Nat. Mu.s. Proc. vol. :,l, 

 p. 509, I91fi. 



1' Cooke, I'. \V.. CarncRic Inst. Washington I'ul). 291, p. 110, 1919. 

 Maury, C. J., ScicutiUc survey of I'orto Rico and the N'irgin Islands, vol. 

 3, pt. 1, p. 5.S, 1920. 



Aperture elongated, acute l)ehind and prolonged into a 

 very narrow posterior canal running straight to the apex; 

 in advance it is gradually narrowed, the anterior notch 

 broad and shallow; inner lip thinly incrusted; outer lip 

 thin in all my specimens, and apparently thin, straight, 

 and entire in the perfect adult. Size of largest speci- 

 men, length 3.75 inches, width 1.5 inches. 



Orthaulax inornalus is the most slender of the 

 known species of the genus. Its apical angle 

 is about 60°, as compared \vith about 85° in 

 0. cutpa and about 95° in <). aijuadillensis. 

 Like those species, it has a circular outline in 

 cross section. In axial sections its most obvious 

 difference from them is in the thinness of the 

 enamel, which in O. inornatus is scarcely per- 

 ceptible but which in both <>. caepa and 0. 

 aguadillerms attains a considerable thickness. 

 In spite of the slenderness of the outside of the 

 shell, the living chamber of Ortlianlax inornatns 

 is more rapidly tapering than thtit of either 

 0. caepa or 0. af/uadUlensi'i, but the whorls 

 themselves are more compressed and Hatter. 

 These features, of course, can usually be made 

 out only by cutting the shell or from casts of 

 the interior. 



Localities: Upper part of bluff of Rio 

 Yacjue del Norte at Btiitoa, Province of Santi- 

 ago, Dominican Rej)ublic, station 8668, Oondit, 

 collector, 1919: Ballast Point, Tampa Bay, 

 Fla., Post, collector. 



Geologic horizon: Baitoa formation, lower 

 Miocene; Tampa formation, upper Oligocene. 



Type: Philadelphia Academy of Ntitural 

 Sciences, from vSanto Domingo, Gtibl). 



Orthaulax pugnax (Heilprin) Dall. 



Plate II, ligures 7, S; Plate III, figures la^b. 



Wdgnerhi j>iii/)iiir Heilprin, Wagner Fi'ee lust. Sci. Trans., 



vol. I, ]!. Kill, 111. 15, figs. 36, ,36a, 1887. 

 Ortliniihir piii/iidj- hall, Wagner Fi'ee Inst. Sci. TraiLs., 



vol. 3, p. 170, pi. 8, figs. 5, 8, 1890; U. S. .\at. Mus. 



Bull. 90, p. ,S7, pi. 1.5, figs. 5, 10, 1915: l'. S. Nat. 



Mus. Proc, vol. 51, p. 509, i91(i. 

 Cooke (part), Carnegie Inst. Washington Pub. 291, 



p. 115, pi. 2, lig. 4, 1919. 



Heilprin (lescribcd <hili(ntJax piiijuar ;is fol- 

 lows : 



Shell irregularly oval, obcouical, llattened, the llattened 

 appearance l>eing due to three irregular swellings or knobs, 

 one of which immediately adjoins the anterioily directed 

 fissure of the aperture; aperture narrow, projected forward 

 ( in its upper course I as a closely compressed fissure, which 

 in a crescential curve ascends to witlun a comparatively 

 short distat.ce of the apex nf the spire; outer lip'.' ( broken 

 in specimen); inner lip largely developed, completely 



