ON A REMARKABLE CASE OF AFFINITY BETWEEN ANIMALS. 415 
28. On a Remarkable Case of Affinity between Animals 
inhabiting Guiana, W. Africa, and the Malay Archi- 
pelago. By OxprieLp THomas, F.R.S., F.Z.S.* 
[Received April 28, 1914: Read May 5, 1914.] 
INDEX. Paze 
Introduction ........... season occ sanesdaanscdaab cog Hull 
E Gtesini Sg, n., or Guicre: Mm baadocaadtancn asl 
In the lower Vertebrates a considerable number of cases are 
known where there is an undeniable and direct attinity between 
forms inhabiting the opposite sides of the Atlantic, but among 
mammals such cases are excessively few, so that the discovery 
of an additional one deserves a special record. That this case, 
like the others, may be explainable without recourse to a land- 
bridge—which there is little reason to believe persisted into 
mammalian times—does not make it any the less advisable to 
publish the case, so that it may be properly considered by 
students of the subject. 
Examples of a striking relationship between certain mammals 
of West Africa and of the Malay region are of course numerous, 
however difficult to explain quite satisfactorily, but it is note- 
worthy that the present instance of transatlantic affinity is also 
one of the best marked of the West Africa-Malay cases, and one 
that has been often recorded in that connection. 
This is the case of the Pigmy Squirrels, of which there are 
some half dozen species in the Malay Archipelago, while a single 
form—Sciurus minutus Du Chaillu, the basis of my genus 
Myosciurus—inhabits Western Africa. Of the close relationship 
of Myosciurus to the Hastern Vannosciwrus there can be no 
doubt whatever. 
In 1789 Buffon described = a little squirrel from Cayenne as 
“Le petit Guerlinguet,” a technical name, Sciurus pusillus, being 
attached to it by Desmarest later on. Then in 1867 Gray 
described a small squirrel bought from the dealer Parzudaki and 
said to have been collected by Castelnau in Brazil, as Macroxus 
kuhlii, and this was, and I believe rightly, synonymized with 
S. pusillus by Alston and other authors. Probably the specimen 
was not collected by Castelnau at all, but was accidentally included 
with Castelnau specimens by Parzudaki. 
The skulls, both of this specimen and of another which was 
obtained by Mr. H. ©. Rothey in Cayenne in 1845, were un- 
fortunately so broken that no proper judgment on the characters 
* Published by permission of the Trustees of the British Museum. 
+ [The complete account of the new genus described in this communication 
appears here, but since the name and a preliminary diagnosis were published in the 
* Abstract,” ‘No. 133, 1914, the genus is distinguished by the name being under- 
lined.—Ep. ] 
+ Hist. Nat. Supp. vil. p. 263, pl. 66. 
