Clark: The San Lorenzo Series of Middle California 177 



Family Thaisidae 

 Genus THAIS Bolten 



THAIS PACKI, n. sp. 

 Plate 19, figures 2 and 13 

 Type specimen 11246, Coll. Invert. Palae., Univ. Calif., lot. 1309 



Shell heavy, medium in size ; whorls five ; spire acute ; sutures slightly de- 

 pressed; body whorl strongly and regularly convex, nearly three-fourths the height 

 of shell; whorls of spire only slightly convex. Surface of shell sculptured by 

 heavy, flat-topped ribs, separated by much narrower interspaces. Spiral ribs on 

 body whorl about sixteen and on whorls of spire usually five. Mouth elongate- 

 ovate; outer lip thickened internally. About ten elongate teeth on inner margin 

 of outer lip ; these reach from the thickened inner portion to the outer edge ; 

 inner lip slightly depressed, intrusted. Umbilicus subperf orate ; canal short, 

 straight, deep and narrow. 



Dimensions. — Type specimen: height of shell, 35 mm.; height of body whorl, 

 25 mm. ; greatest width of body whorl, 24 mm. 



Named in honor of E. M. Pack, palaeontologist on the United States Geological 

 Survey. 



Occurrence. — University of California localities 14, 52, 1131, 1309, 1343, etc. 



This species superficially resembles T. lima Martyn, 143 a common 

 and variable species on the West Coast, from which it differs in the 

 character of the spiral ribs and in the denticulations on the inner 

 margin of the outer lip ; also the shell is heavier. It differs in the 

 same respects from T. precursor Dall, 144 a form from the Pliocene 

 of Coos Bay, Oregon. 



Family Fusidae 

 Genns FUSINUS 

 FUSINUS (PEISCOFUSUS) HECOXI Arnold 

 Plate 22, figure 7 



Fusus hecoxi Arnold, Proc. Nat. Mus., vol. 34, p. 371, pi. 33, fig. 8, 1908. 

 Fusinus (Friscofusus) hecoxi Arnold, Clark, Univ. Calif. Publ., Bull. Dept. 

 Geol., vol. 9, no. 2, p. 15, 1915. 



The aperture and canal on Arnold's type were missing. The 

 specimen here figured shows the aperture to be elongate-ovate ; the 

 inner lip is rather heavily incrusted and the canal narrow, slender, 

 fairly long, and straight except near the anterior end, where it is 

 slightly recurved. 



143 r r description and figures of Thais lima., see Tryon, Manual of Conchol- 

 ogy, vol. 2, p. 175, pi. 53, figs. 156, 158, 159, 161, 1880. 



144 For original description of Thais precursor, see U. S. Geol. Surv., Prof, 

 paper no. 59, p. 51, pi. 4, fig. 4, 1909. 



