MUSEUM OF COMPARATIVE ZOOLOGY. 113 



Mangilia, and I suspect it to be a differently colored dwarf form of what I 

 afterward called atrostyla. 



M. serga has a larger and differently sculptured larval shell, a much sharper 

 and more rasp-like sculpture with a few spirals larger than the rest; the angu- 

 lation more peripheral and less marked, the last whorl longer and narrower 

 proportionally, the notch wide but not quite sutural; the suture distinct, not 

 appressed, marginated by a thread; ribs thirteen, no varix; canal longer; ribs 

 narrow, not strong except on the periphery and almost spinose at the intersec- 

 tion of the primary spirals. Lon. of shell, 9.0; last whorl, 5.12; lat. 3.1 mm. 

 Antilles and Straits of Florida. 



M. atrostyla differs from limonitella by larger size, stronger shoulder, deeper 

 suture, having only eight ribs, the last of which forms a strong varix; and in 

 its usual color markings. Lon. 8.75 ; last whorl, 5.0; lat. 3.1 mm. Hatteras to 

 the Antilles. M. ephamilla Bush is an immat"*? color variety of atrostyla 

 proper. 



M. cerinella recalls cerina by its color, is much larger than the genuine cerina, 

 more drawn out and slender ; it has only six or at most seven ribs, a short 

 aperture, no canal to speak of, and hardly any indentation for a notch; the 

 suture is less appressed and undulate ; while the ribs are almost obsolete in 

 the fasciolar region ; the angulation is nearly at the periphery and the slopes 

 either way from it are nearly equal. Lon. 11.75 ; last whorl, 5.87; lat. 3.75 mm. 

 North Carolina to Florida and Texas. 



Mangilia quadrata Reeve. 



Pleurotoma quadrata Reeve, P. Z. S. 1845, p. 114; Conch. Icon. Pleurotoma, pi. xxviii. 



fig. 253 (magnified), 1845. 

 Clathurella quadrata Tryon, Man., VT. p. 278, pi. xviii. fig. 31, 1884. 



Habitat. West Indies, Krebs, Tryon. 



I have no doubt that Krebs and Tryon are right in identifying Reeve's species 

 with P. diminuta C. B. Adams, a name proposed for the West Indian shell 

 should it prove to be different. This species differs from the group of which 

 atrostyla is a type chiefly in its stronger sculpture and consequently prominent 

 outer lip at the resting stages. It has similar nucleus, habits, granular spiral 

 sculpture, and distribution. 



There are several forms which may be treated as varieties, being connected, 

 though the extremes seem widely separated by intermediate forms. 



Mangilia quadrata var. quadrata. 



Shell resembling Reeve's figure, which is three times magnified, though this 

 is not stated in the text. Miss Bush's M. eritima, judged by an author's speci- 

 men before me, agrees well with this variety. The red color mentioned by her, 

 on the pillar and throat, is very rarely developed ; I find it on only one speci- 

 men out of many. Range, North Carolina to Yucatan and the West Indies. 



VOL. XVIII. 8 



