MUSEUM OF COMPARATIVE ZOOLOGY. 145 



The true Volutes of the V. musica type appear in the Red Bluff Eocene. 

 Voluta mississippiensis Conrad, of this age, is identical with V. costata Sow- 

 erby, from the English Eocene. These species are directly derived from 

 Volutilithes. They are small, and would, if recent, be placed in the subgenus 

 Lyria. Their Miocene descendants begin to diverge from one another, some 

 taking on the large form of recent Volutes, others remaining small.* 



None are yet known from the Pliocene, but V. musica and V. virescens 

 inhabit the waters of the Gulf of Mexico and the Caribbean region at the pres- 

 ent day. Lyria, which is not distinguishable generically from the small Mio- 

 cene forms, exists in the shore fauna of subtropical West America, and Voluta 

 or Scaphella will doubtless be found when the depths are dredged, though the 

 latter is not known at present north of Chile. The single Alaskan species, 

 S. Slearnsii, belongs to the group of S. ancilla, with which the late Mr. Sowerby 

 absurdly united it. Its nearest congener in the North American region seems 

 to be the S. Newcombiana of the Eocene, before referred to, but they are not 

 very closely related. V. Lamberti of the English Crag and some Continental 

 Miocene species are nearer to it than any one from our own strata yet known. 



Judged by the recent species the shells of the junonia group are readily 

 separable from those of the dubia group. When the fossils are consulted, it is 

 evident they are genetically connected. I shall, however, retain the sectional 

 distinction of Scaphella proper and Aurinia for the two series, respectively. 



There can be no doubt that the genus Lyria is very closely related to Voluta 

 as restricted ; and the one is doubtless an offshoot from the other, both exist- 

 ing, well characterized, in the Ballast Point Miocene of Tampa Bay. 



That Volutomitra belongs in this family is certain, and I give (Plate XXXIV. 

 Figs. 6 and 7) some unpublished drawings of Stimpson showing the shell and 

 dentition of V. gronlandica. The shell figured is apparently young ; those 

 which I have received from Copenhagen are larger, and have a proportionally 

 longer canal and a little more of the Mitra form about them than these 

 figures. 



The other forms of Volutidce (excluding Lyria) belonging to the Antillean 

 region are all rare shells, and, from their rarity, have' been little studied. 

 The U. S. National Museum possessed five fairly good adult specimens of 

 S. junonia, beside several much more interesting specimens of the very young. 

 Several specimens of S. junonia and A. dubia were obtained by Pourtales in 

 the Floridian region. The U. S. Fish Commission in the same vicinity ob- 

 tained an adult A. robusta, old and young A. dubia, and eight or nine A. Gould- 

 iana in various stages, including one adult living specimen. The very young 

 of A. robusta were dredged by the Blake. In this way, probably for the first 

 time, a sufficient number of these extremely interesting shells for satisfactory 

 study has been brought together. 



* This subject will be more fully discussed in my forthcoming Report on the 

 Tertiary Paleontology of Florida, to be published by the Wagner Free Institute of 

 Science, Philadelphia. 



VOL,, xviii. 10 



