398 TRANSACTIONS OF THE WAGNER FREE 



Though represented by a very imperfect, single specimen, this shell is 

 undoubtedly different .from either fossil or recent forms from our coast yet 

 known, and recalls the European C. conulus. I have delayed figuring it in 

 the hope of securing a better specimen, but the characters are so distinct that 

 it cannot be mistaken for any other American species. 



Oalliostoma eboreum Wagner. 



Trochus eboreus Wagner, Journ. Acad Nat. Sci. Phila. viii. p. 52, pi. i, fig. 5. 1838. 

 9 Monilia {Leiolrochus) eborea Conrad, Proc. Acad. Nat. Sci. 1S63, p. 569 ; Meek, Miocene 

 Checklist, p. 15, 1864. 



Miocene of the Patuxent River, Maryland (Wagner), and of Shiloh and 

 Jericho, New Jersey, Burns; also near Church Hill, Md., Harris. 



This species is a typical Calliostoma, with a rather angular periphery 

 which forms a line over the suture below it, a polished surface, mostly smooth, 

 with a few fine but distinct, elevated spiral threads, rather irregularly disposed 

 and sometimes absent. The base is generally smooth, flattish, imperforate, 

 with the usual arched pillar ending in an obscure projection (common to the 

 genus) and a few spiral threads about the umbilical region. Old specimens 

 have the last whorl less angular at the periphery, the base rounded and the 

 aperture less quadrate than in smaller specimens. The threading is irregular 

 and occasionally profuse or entirely absent. 



The type of Conrad's genus which he called Leiotrochus (Proc. Acad. 

 Nat. Sci. 1862, p. 288) is L. distans Conrad, a species described as follows : 

 " Trochiform ; volutions 4 ; suture subcanaliculate near the apex ; revolving 

 lines, a few distant, distinct, impressed, the others very fine ; periphery 

 rounded; base convex-depressed, with six distant, impressed revolving lines 

 and very fine intermediate lines ; umbilicus narrow, profound ; subcarinated at 

 base. Locality, Calvert Co., Md. ?" The shell appears never to have been fig- 

 ured under this name, nor could the type be found in Philadelphia, but it agrees 

 well with a species which he afterward described and (badly) figured under the 

 names Zisyphimcs punctatus and Briani, and which comes from the locality 

 mentioned. The following year Conrad, in his " Catalogue of the Miocene 

 Shells of the Atlantic Slope," reduces LciotrocJius to subgeneric rank, places 

 it under Monilia (sic) Swainson, and includes with his tj'pe Troclms eboreus 

 Wagner, Turbo caperatits Conr. and Monodonta ( = Omphalius) kialnvahensis 

 Tuomey and Holmes. He gives the following diagnosis of the subgenus 

 Leiotroclms : " Polished, entire, without umbilicus ; base of columella with two 

 denticles." On the next page (570), under Carinorbis ( ^ Fossarus), we find the 

 same species, distans, with the same references as before ! To add to the 

 confusion, about the date of the above catalogue a set of Tertiary fossils named 

 by Conrad was presented by Haldeman to the Smithsonian Institution which 

 included several specimens of a shell labelled " Monilia eborea (Wag.) Conn, 



