368 CRETACEOUS GASTROPODA 
umbilical margin crenulated. The genus was founded upon two species, H. japonica 
and speciosa, which were dredged in deep (63 fathoms) water in the Japan sea. 
Deshayes in his last edition of the Paris fossils describes several small species which perfectly 
correspond with the characteristics given by Adams. Of cretaceous species Zurbo Guerangert, 
d’Orb., and others, appear to be nearly allied in form, but they have a much thicker shell. Zurdo 
delphinuloides and T. Lyelli, d@Arch., and others, seem to be representatives in the jurassic 
formations, but it is doubtful if the distinctions from So/ariedia are really of a generic value. 
32. Margarita, Leach, 1819 (H. and A. Adams, Gen. I, :p. 483). Shell 
suborbicular or conically elevated with short spire, thin, smooth or spirally striated, 
aperture nearly circular, margins slightly expanded, edge of umbilicus not crenu- 
lated. ‘The recent species which are numerous mostly inhabit northern seas or 
in the tropics deep water, being therefore readily distinguished by their thin 
shells. The principal difference from Solariel/a consists in the want of a crenulated 
edge of the umbilicus and a more roundish aperture. 
Tertiary species are rather rare, and of cretaceous I can only mention Mary. Nebrascensis, 
M. and H. (Proc. Phil. Acad., 1856, p. 54), and MM. abyssina, Gabb, sp. (Smith. Miscell. Coll. 
No. 177, p. 18) from North America; a third species will be described under the name of Marg. 
orbiculata from South India. 
d. Sub-family—DELPHINULIN &. 
Shell orbicular or broadly conical, whorls tubular. 
33. Delphinula, Lamarck, 1803 (Angaria in H. and A. Adams’ Gen. I, p. 411). 
Whorls generally spirally ridged and often coronated, the last one at the aperture 
usually detached from the previous one, margins continuous, sharpened from within, 
sometimes a little enlarged, but not thickened. 
The recent species of Delphinula are mostly of a large size and of a depressed form, with the 
whorls superiorly coronated. They are shells of the eastern and warmer seas, being rare in tertiary 
deposits, but more common in cretaceous. Species represented by the type Del. turbinopsis, Lamarck, 
are distinguished by their more slender form and elevated spire ; they also are rather rare in tertiary 
and eretaceous deposits, being, however, very common in jurassic* and even in triassic rocks ; last 
there are species represented by the Delph. lava, Say, having the whorls almost smooth and more or 
less uncoiled. Of this form I only know the original figure of Say and that given by Chenu, but 
Mr. G. Nevill lately collected on the Ceylon coast a species which comes nearest to it, excepting 
that it has the first whorls regularly coiled, not detached from each other. The jurassic Turbo 
Archiacii and Stomatia sulcosa of V@Orbigny most probably belong to this type of Delphinula. 
I have already remarked when speaking of the Liormp2, that all the small species with trans- 
verse ribs and usually largely expanded and thickened margin of the aperture have nothing to do 
with true Deiphinule. On this account many errors have been committed in fossil Conchology, 
because not only species of Liotia, Craspedotus, and Cyclostrema, but also of Crossostoma, Chrysostoma, 
Umbonium, Straparolus, and others have been at various times referred to Delphinula. It will still be 
some time before all these mistakes can be emended. 
Of cretaceous species I consider the following as most probably belonging to Delphinula : 
Turbo munitus, Forbes, 7. Thurmanni, Pict. et Camp., Turbo sulcifer and Delphinula coronata of 
Roémer, D. spinulosa, Binkhorst (Monog. Gast. et. Ceph. eraie, Limbg., p. 54). Gabb. (Pal. Calif., 
1864, I, p. 121, pl. 20, fig. 78) deseribes an Angaria ornatissima, but I rather think the species to 
* Turbo Eudoxus, subfunatus, epulus and Davoustii, d’Orb., Turbo segregatus, Heb. and Desl., and others. 
