146 PATAGONIAN EXPEDITIONS : PALEONTOLOGY. 
found there, v. Ihering says himself (1899, P- 43 ) that this identification 
is doubtful. But the presence of this species in the Cape Fairweather beds 
affords some support to v. Ihering’ s original opinion. 
Affinities : As v. Ihering points out, this species is very closely allied 
to Artemis ponder o sa Gray (see: Philippi, 1887, p. 113, pi. 14, f. 5, and 
Moericke, 1896, p. 585), which is found in the Pliocene Coquimbo beds 
of Chili, and living on the western coast of Mexico. The latter form, 
however, is larger, and the concentric sculpture is less marked in the 
middle of the shell. The hinge agrees closely in both species, and even 
the lunula, although there is a slight difference as v. Ihering points out, 
is almost the same, and differs from other species of Dosinia. 
D. ponderosa is represented in the Miocene deposits of California by 
D. mathewsoni Gabb (1869, p. 57, ph 15, f. 16), which differs from D. 
meridionalis in the more swollen form, but agrees well in size. 
A very close resemblance exists also to D. acetabulum (Conr.). Al- 
though, in comparing the figure given by Whitfield (1894, pi. 13, f. 2), 
and copied from Conrad, this resemblance is not so very striking as regards 
the sculpture, I have compared specimens from Virginia, in which the 
sculpture is essentially identical. The only difference is the large size, 
and the less excavated lunular margin of I), acetabulum . D. acetabulum 
is from the Miocene of the Atlantic coast of N. America. 
D. denselineata Pritchard (1896, p. 135, pi. 4, f. 5 - 7 ) seems to be closely 
allied to D. meridionalis , especially in sculpture, but the outline is dif- 
ferent : the posterior dorsal margin appears longer, and forms a more dis- 
tinct angle posteriorly. It is from Table Cape, Tasmania and Spring 
Creek, Victoria. 
Thus the presence of this comparatively large and typical Dosinia in 
the Patagonian beds points clearly to a Neogene age, and this view is 
still more supported by the fact, that D. meridionalis is apparently closely 
related to, and perhaps the ancestral form of a species that is still found 
living on the western coast of America. Probably all the forms mentioned 
above are connected genetically. 
