Author Description

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1903 edition. Excerpt:...series at San Pedro, and is now in the collection of Delos Arnold. Liv;ing.--Guatemala (Carpenter). Pleistocem.--San Pedro (Arnold). 157. Planorbis vermicularis Gould. PLATE IX, Fro. 14. Planorbis vermicularis GLD., Proc. Bost. Soc. Nat. Hist., Vol. II, 1847, p. 212; Wilkes' Expl., Exped., Vol. XII, p. 112, fig. 131, 1852. CPR., Brit. Assn. Rept., 1863, p. 675. Shell small, dome-shaped; spire sunken into cup shaped depression below upper margin of body-whorl; whorls four, breadth and height about equal, the last one deflected near the aperture, rounded at periphery; suture very deep, the whorls sloping toward it; base cup-shaped, exhibiting all of the whorls; aperture exhibiting a very oblique section of a cylinder; slightly expanded, embracing about one-half the height of the last whorl, and joined by callus. Dimensz'on.r.--Alt. 6 mm.; maximum diam. 11.5 mm. Specimens identified by Dr. Dall. _ Rare in the upper and lower San Pedro series at San Pedro; three specimens. The specimen figured is from the upper San Pedro series at San Pedro, and is now in the collection of Delos Arnold. A Shell small, sinistral, shining, pellucid; whorls five ventricose; suture distinct; aperture oval; outer lip thin; pillar lip strong and forms a conspicuous sinus where it joins the whorl above. Dimmsions.---Long. 12 mm.; lat. 7 mm.; body-whorl 10 mm_.; aperture 8 mm.; dell. 95 degrees. This fresh-water form, together with several other species having the same habitat, was found in the lower San Pedro beds at San Pedro. There is no doubt as to their occurrence in these marine deposits, into which they were probably washed by some fresh-water stream. Shell oval-conoidal, or suboval, solid; spire rather short; aperture elongated, narrow; columellar lip...