4 DR. F. E. BEDDAKD OX 



1904, from an example without a skull, as Midas goeldli, but 

 which had recently been redescribed by'Di\ Ribeiro, from the 

 living animal, as Ccdlimico snethlageri, a new genus and species 

 " intermediate between Callicehus and Mico." 



Mr. Thomas's examination of Dr. Ribeiro's type specimen, sent 

 over by the authorities of the Para Museum, showed that Galll- 

 mico really was intermediate between the Cebidse and Callitrichida;, 

 having the external characters of a Marmoset, notably the elon- 

 gated claws, combined with the shape of skull and molar formula 

 'of the Gebidse. The molars themselves possessed no hj'pocone, as 

 in the Marmosets. 



The animal being, therefore, intermediate in character be- 

 tween the two families Oebid?e and Callitrichidse, there was great 

 difficulty in deciding as to the efiect its discovery should have on 

 the systematic arrangement of the American Monkeys, and as to 

 whether these two families ought still to be kept separate. 



On the whole, as causing least disturbance, Mr. Thomas thought 

 that the best plan would be to form a special subfamily, the Calli- 

 miconinae, for Callwiico, and to include this as a second subfamily 

 with the Oebinse in the family Cebidfe. But that Callimico was 

 a real genetic link between the two families there seemed to be 

 no doubt whatever. 



PAPERS, 



1. Contributions to the Anatomy and Systematic Arrange- 

 ment of the Gestoidea. By Feank E. Beddakd, D.Sc, 

 M.A., F.R.S., F.Z.S., Prosector to the Society. 



[Received September 27, 1912 : Read October 29, 1912.] 



(Text-Hgures 1-10.) 



YII. Ox Six Species of Tapeworms from Reptiles, 



BELOXGIXG TO THE GeNUS IcUTHYOTJENIA (s. I.). 



Index. 

 Sjstematic : Page 



Species of Iclithyotcenia {AcantJiotcBJiia) 5 



IcIitJi^otcenia {Acantliotcenia) sp 6 



I. (Acanthoteeiiia) nilotica, S'p. n 11 



I. (AcantJiotcBnia) sp 16 



I. (AcanthotcBnia) varia, sp. n 17 



I. (AcantJiotcBnia) gracilis, sp. n 23 



OpJiidotcenia, gen. nov 35 



O. naice, sp. ii 25 



Genera of Ichthyotaeniidae 34 



Resume 36 



The genus Ichthyotcenia (whose possible subdivisions I discuss 

 iater) is chiefly foutid among freshwater fishes — that is, most of 



