108 PARTULINA, SECTION BALDWINIA. 



1 1 



Animal in motion longer than the shell. Mantle black, 

 margined with gray. Foot above and below gray, the superior 

 portions lightly granulated. Tentacles light gray ' (Bald- 

 win). 



Hawaii : Above Kukuihaele, Hamakua, type loc. ; ridges 

 above the Waipio and Waimanu valleys ; above Honakaa and 

 Kukaiau (see p. 92) . Fossil in the Mana deposits. 



Achatinella horneri BALDWIN, Proc. A. N. S. Phila,, 1895, 

 p. 224, pi. 10, figs. 20, 21, 22. HENSHAW, Journ. of Malac., 

 xi, p. 63. 



Distinguished from P. confusa by its shorter spire, much 

 more inflated, broader last whorl, and the less roughened, 

 more even and shining surface. Moreover, the embryo has no 

 zigzag-striped stage. Named in honor of Mr. J. Lewis 

 Horner. The following color-races are found. 



(a) PI. 17, fig. 1. White, with a brown band at the periph- 

 ery, ascending the spire in a narrow line above the suture. 

 Size large, length 23.5, diam, 18, aperture 14.6 mm. ; 6 whorls. 



(ft) PI. 17, figs. 2, 5. Brown, with a narrow white band 

 below the suture, one above, another below the periphery. 

 The brown fades on the penultimate or on the last whorl, 

 which in large part or entirely is white. 23 x 16.4 mm. 



(c) PI. 17, figs, 3, 4. White, with a pale brown band im- 

 mediately below the periphery, which fades out on the fifth 

 whorl, being visible therefore only in immature shells, the 

 adult stage pure white throughout. Embryo ivory-white 

 with a distinct brown subperipheral ba.nd. 22 x 15.5 mm. 

 Above Kukuihaele, Hamakua, 



(d) Young stage light brown, darkest just below the 

 periphery; adult white with pale brown spire. Embryo bi- 

 colored, pale brown above, darker brown below the periphery. 

 20.5 x 15.5 mm. Above Kukuihaele. 



These several color-forms are evidently incipient races, as 

 they O'Ccur in pure colonies, so far as known. Races c and d, 

 Mr. Thaanum informs me, occur three or four miles apart. 

 The embryonic forms are much more distinct than the adults, 

 and are constant in the colonies. 



By the loss of zigzag stripes on the embryo and young 



