352 BULLETIN OF THE 



tives in Japan and Califomian waters. It has a few-whorled rather solid 

 smooth discoid shelly operculum a little concave externally, no umbilicus 

 when adult, and a rounded base. The name Leptonyx having been used twice 

 for Vertebrates before Dr. Carpenter took it up, I substituted Leptothyra * 

 with his permission, as above cited, in 1871. A further confusion was created 

 in regard to the type species by a supposition that the operculum of the Cali- 

 fomian shell was different from that of the Mediterranean. This idea was 

 totally erroneous, but found its way into several publications, among others 

 Tryon's Manual (II. 312). The opercula are precisely alike, having a por- 

 cellanous coating, a little thicker at the edges than toward the centre, espe- 

 cially in old specimens, and having the general form of a coin or disk (not of a 

 lens) based on a horny substratum, as in the typical Naticas. The operculum 

 has about five to seven turns, visible best on the inner side. The young shells 

 have a pit, or even a perforation, in the umbilical region, but this is entirely 

 effaced in the adult, unless L. Philipiana is an exception. 



L. sanguined is not yet known from the east coast of America. We have, 

 however, beside L. induta and what I regard as its varieties, two other species, 

 L. Philipiana and L. Linnei, now for the first time described. 



A shell which I find in the Jeffreys collection marked " Turbo carinatus 

 Cantraine, Travailleur Exp., 1882," is a remarkably fine species of Leptothyra, 

 larger than any other known to me. Turbo mammilla of the Reggio Tertiaries, 

 as identified by Prof. Seguenza, is also a Leptothyra, and so probably is Turbo 

 filosus Philippi of the Italian Tertiaries. 



Leptothyra induta Watson var. albida Dall. 



Plate XXXVIII. Fig. 6. 



Leptothyra induta Dall, Agassiz, Three Cruises of the Blake, II. p. 69, fig. 287, 1888. 

 Leptothyra (induta var.?) albida Dall, Bull. M C. Z., IX. p. 48, 1881. 

 Turbo (Collonia) indutus Watson, Journ. Linn. Soc, XIV. p. 715, 1879; Chall. Rep. 

 Gastr., p. 128, pi. vi. fig. 1, 1885. 



Habitat. Sand Key, in 15-128 fms. ; Station 2, in 805 fms.; Sigsbee, off 

 Havana, in 450 fms.; off Cape San Antonio, in 1002 fms.; Yucatan Strait, in 

 640 fms.; Station 5, in 152-229 fms., soft coral ooze, bottom temperature 50° ; 

 Station 100, off Morro Light, Havana, in 250-400 fms.; Station 211, off 

 Martinique, in 357 fms.; Station 218, off Santa Lucia, in 164 fms., bottom 

 temperature 56°.0. U. S. Fish Commission Station 2662, off St. Augustine, 

 Florida, in 434 fms., gray sand. 



Variety tincta Dall, shell rosy. 



Variety insculpta Dall. Ridges obliquely cut by the radiating sculpture 

 which nodulates them all, and extends entirely over the shell; basal ridges more 

 numerous (six), close, and slightly but distinctly sculptured by the radii. 



* The name Homalopoma was under consideration by Dr. Carpenter as a sub- 

 stitute for Leptonyx, but was never published by him. 

 April 24, 1889. 



