392 MICROMELO. 



calls the species " undulata Brug.," and because the shell he meant 

 was not the species of Bruguiere. Neither have I followed v. Mar- 

 tens in giving B. guamense as the type of Ferussac's group, because 

 Ferussac did not mention that species, and the identification of his 

 " B. undulata Brug." with guamense is only hypothetical, although 

 extremely probable. Surely if such an identification be sufficient 

 to fix the identity of the genus, it is enough to fix that of the spe- 

 cies ; and v. Martens does not go so far as to call guamense " undu- 

 lota Fer.," as he would be compelled to do were his view followed 

 to its logical conclusion. 



M. UNDATA Bruguiere. PI. 59, figs. 20, 21, 22, 23, 24. 



Shell oval, rather thin, white with two or three equidistant spiral 

 red lines and many deeply sinuous longitudinal red lines. Surface 

 shining,showing under a lens many unequally spaced spiralscomposed 

 of rounded pits just touching each other; this sculpture oftennearly 

 obsolete and hardly visible except at the base. Vertex rather nar- 

 row, the spire nearly level ; first whorl a shining, uptilted, nearly 

 immersed nucleus ; following whorls separated by impressed sutures. 

 Aperture long, pear-shaped, gradually narrowed and curved to the 

 left above, broadly rounded below ; lip receding a trifle at suture. 

 Columella broadly concave, with reflexed, appressed edge. Alt. 

 12*, diam. 8} mill. 



St. Thomas (Swift, Krebs, et al.) ; St. Vincent (Guilding) ; St. 

 Martin (Krebs) ; Cuba (Sagra). 



Bulla undata BRUG., Encycl. Meth., i p. 380. ORB., Moll. Cuba i, 

 p. 132. Bullina undata MOROH, Mai. Bl. xxii, p. 174. Bulla niti- 

 dula (Solander, MSB., Portland Catal., undesc.) DILLWYN, Descript. 

 Catal. Recent Shells, i, p. 483. A. AD., Thes. Conch., ii, p. 565, pi. 

 120, f. 15, IQ.Hydatina nitidula SOWB., C. Icon., f. 1 (false local- 

 ity.) Bullina elegans MKE., Syn. Meth. Moll. Mus. Menkeano, edit. 

 2, 1830, p. 13 (founded upon Lister's figures). 



The spiral red lines often occupy the middle of an ill-defined 

 reddish band, and frequently the median line is wanting. 



M. GUAMENSIS Quoy & Gaimard. PI. 59, figs. 25, 26. 



Shell ovate, pellucid, grooved by several black undulating longi- 

 tudinal lines and three transverse lines. It is covered by a thin 

 extended epidermis, and is wider in front than behind. The obtuse 

 re-entrant spire describes a little more than two whorls ; the ground 



