MUSEUM OF COMPARATIVE ZOOLOGY. 375 



It may be worth while to remark, as Leach's * book is a very rare one, that 

 Vol. I. pages 1-57, plates i.-xxv. inclusive, were published in 1814; pages 57- 

 129, plates xxvi.-lvii., probably in 1814; and the remainder certainly in 1815, 

 as I have ascertained from contemporary advertisements issued with the parts. 

 The genus Bulhnulus, types B. acutus (Mull.), p. 41, and B. trifasciatus Leach, 

 p. 42, would therefore date from 1814, also Margarita (type the mother of pearl 

 shell of commerce), p. 107, and Dipsas (plicatus Leach), p. 119. Aciona Leach 

 (type Scalaria pretiosa Lam.), Vol. II. p. 79, dates from 1815. 



Section MARGARITA s. s. 

 Margarita erythrocoma n. s. 



Plate XXVIII. Fig. 1. 



Shell small, depressed conic, yellowish, variegated and articulated with 

 rose-pink and opaque white ; whorls rounded, four or five in number, with a 

 minute smooth nucleus ; generally a little carinated on the upper surface, es- 

 pecially the earlier whorls, by one or two prominent spiral riblets; below full 

 and rounded, with a small but well marked umbilicus. Radiating sculpture 

 of the lines of growth occasionally irregular so as to form faint waves, but 

 usually inconspicuous; spiral sculpture of fine close little-raised threads, with 

 on the upper surface one and on the periphery another stronger thread or 

 carination, seldom nodulous, and stronger on the earlier whorls. The spirals 

 are usually articulated with rose-red and opaque white or greenish yellow. 

 The base is rounded, finely spirally threaded, umbilicus not carinated nor 

 marked by special sculpture. Aperture rounded, oblique, the margins a little 

 angulated above, thin, simple, joined by a thin layer of callus on the body. 

 Alt. of largest specimen, 5.0; max. diam., 5.25; inin. diam. of base, 4.0 mm. 



Variety ? samance. Shell more depressed, last whorl proportionately larger, 

 and aperture much more oblique; umbilicus twisted, nearly closed, white with 

 radiating flexuous strice; shell colored like the typical form and with similar 

 early whorls. Alt., 4.75; max. diam. of base, 5.75; min. diam., 4.25 mm. 



Habitat. Off Sand Key, in 54 fms. Samana Bay, St. Domingo, and Nassau, 

 Bahamas, U. S. Nat. Mus. 



The variety. Samana Bay, in 16 fms., Couthouy. 



This very pretty little species occurs with Liotia miniata in moderate depths of 

 water. The specimen from 54 fms. was probably drifted. It may be distin- 

 guished from the Liotia, which is about the same size, by the different characters 

 of aperture and umbilicus. There is no northern species which resembles it. 



* The Zoological Miscellany | being | descriptions of new or interesting animals | 

 by William Elford Leach, M.D. F.L.S. & W.S. | [etc.] | illustrated with | colored 

 figures drawn from nature | by R. P. Nodder [etc.]. London, Printed for E. Nodder 

 & Son, 1814. | Second title, issued with the concluding part, has a quotation and 

 " Vol. I.," added before " London," with date 1815. Total, Vol. I., 144 pp., 8vo, 

 60 colored plates ; Vol. II., 161 pp., plates 61-120, " 1815." 



