316 PARTULA, MARIANNE ISLANDS. 



little more separated above the periphery. The surface is 

 glossy. The lip may be narrow and nearly uniform in width, 

 but usually it is rather strongly thickened inside, the callus 

 abruptly discontinued near the posterior curve. The color 

 -of the lip is quite variable. There is a callous nodule deep 

 within, near the columella, but it is very variable in size. 

 The suture may be marked with a whitish line, but often this 

 is absent. No specimen I have seen has a well developed 

 white band along the suture, such as is usual in P. gibba 

 The color-patterns known are as follows : 



(a) Straw colored or isabelline, with a reddish-brown band 

 above the suture almost to its end, and covering the first 

 li/o whorls; outer half of the lip brown, inner rim 

 white. This is the typical coloration (figs. 12). 

 (&) First 2 whorls purplish-brown, the third pale below the 

 suture with the dark color fading (or the subsutural 

 pale area may extend nearly to the apex) ; last 2 whorls 

 straw yellow or pale isabelline with faint or distinct 

 brownish streaks ; back of lip reddish or yellow ; lip 

 narrow, very pale brown; surface rather dull (fig. 18). 



(c) Same as the last but without brown on the spire; sur- 

 face lusterless (fig. 15, 16). 



{d) Pale uniform sulphur-yellow throughout, the lip 



brown- tinted or brown-edged (fig. 14). 

 (e) Pale sulphur-yellow, the lip heavily thickened and 



pure white (fig. 13). 

 The size varies as follows : 



(a) Length 17, diam. 11.5, aperture 10 mm.; whorls 4%. 

 {&) Length 17, diam. 11, aperture 9.5 mm.; whorls 4i/o. 



(d) Length 16, diam. 11, aperture 9.4 mm.; whorls 4 1 /4. 

 (c) Length 15.7, diam. 10, aperture 9.1 mm.; whorls 4y 2 . 



110. P. RADIOLATA (Pfeiffer). PI. 41, figs. 1, 2, 3, 4. 



Shell subperf orate, oblong-tapering, the apex obtuse, thin; 

 sculptured with distant impressed spiral lines; pale straw- 

 colored, rayed with darker streaks and brown lines. Whorls 

 5, slightly convex, the last about equal to the spire, base 



