1875. ] MR. R. J. L. GUPPY ON HELIX COACTILIATA. 319 
and includes Central America. Amongst other Mollusca the Heli- 
cine and Bulimi of the latter region are of South-American types, 
the truly North-American fauna being characterized by the absence 
or comparative rarity of those genera and the development of pecu- 
liar forms of depressed and toothed Helices. These considerations 
invest with some interest the occurrence in South America of Helix 
labyrinthica and of a form so near to H. ericetorum as H. coactiliata. 
It is, however, well known that there are other South-American 
Mollusea which have affinities somewhat similar *. 1 shall proceed 
to remark upon a few of these alliances. The South-American 
Bulimus bilabiatus finds a relation in the B. auris-vulpina of St. 
Helena. Still more curious is the distribution of so well-marked a 
genus as Streptazis. It is found in South America, Bourbon, 
Rodriguez, Ceylon, India, and China. Bulimus constrictus of Vene- 
zuela, and a shell found by me in Trinidad and described as B. pilo- 
sus, have some remarkable points of resemblance to two St.-Helena 
shells called B. digitalis and B. helena. We may remember also 
that the genera Anostoma and Megaspira, found fossil in the Eocene 
of Europe, are living in South America. This combination of facts 
is difficult of explanation when we consider that one portion of the 
affinities is with the early Tertiaries of Europe, and another with the 
existing fauna of the Indian and Chinese regions. The Miocene 
fauna of the West Indies exhibits similar relations. An explanation 
will doubtless be found; and it will probably include the hypothesis. 
which assumes a land connexion between the opposite sides of the 
Atlantic in Tertiary or Cretaceous times. I have not alluded to the 
occurrence of two East-Indian Mollusca in the West Tndies—namely 
Pupa (Ennea) bicolor in St. Thomas, Grenada, and Trinidad, and 
Diplommatina huttoni in the latter island; for one of these species 
may have been introduced, though there is more doubt as to that 
being the case with the other t. But from the botanical, no less 
than the zoological, evidence I am inclined to believe that the con- 
nexion between the eastern and western continents existed in Meso- 
zoic times, and that it was the disruption of this connexion that 
determined the Cretaceous period, and caused the wide biological 
gap between that period and the Eocene. Some eee on this 
head based on paleontological evidence will be found in papers 
written by me in 1866§. But I now state the conclusion to which 
I have been drawn in broader terms; and I would further insist 
upon the proposition that the land connexion (which need not at 
any time have been continuous) extended from the now sunken 
Caribbean continent to northern Africa. For facility of explanation 
* See Forbes, cited by Woodward, Man. Moll. second edition, p. 96, 
+ The Pedipes glaber of the English Eocene is a South-American form. It 
belongs to that section of Cionella called Leptinaria. The Achatina costellata 
of Sowerby is a species of Glandina—a genus belonging to the West Indies and 
Central America. 
{ See Ann. & Mag. Nat. Hist. 3rd ser. vol. xx. p. 95, and 4th ser. vol, i. p- 110; 
also Amer. Journ. Conch. 1870, p. 308. 
§ Quart. Journ. Geol. Soc. vol. xxii. p. 584, and Geol. Mag. vol. iv. (1867) 
. 496. 
P 
