Art. XIX. — Nein or Little- Kiiovm Victorian Fossils in 

 tlte National Museum. 



Part III. — Somk Palaeozoic Pteropoda. 



By FREDERICK CHAPMAN, A.L.S., &c., 



National Museum. 



(With Plate XXXI.). 

 [Bead 8th December, 1903]. 



With regard to the zoological relationship of the fossils 

 described in this paper there is much diversity of opinion, and 

 they are here referred to the Pteropoda with a certain amount of 

 reserve. Nicholson has shown that by the presence of a bulbous 

 commencement or protoconch, Tentaculites, one of the genera 

 now described, seems to bear a decided relationship with the 

 more recent pteropods, as Clio. The absence of any signs 

 of attachment to a foreign body which might be seen on the 

 shell, as well as its general structure, precludes one from referring 

 the typical Tentaculites to the Tubicolar Annelides, as some 

 have done. 



Haeckel and Pelseneer, on the other hand, exclude all pre- 

 tertiary forms from the group of the Pteropoda. 



So far as the present evidence goes, the Palaeozoic examples of 

 Styliola and Tentaculites seem to be, zoologically, closely related, 

 the former genus being usually distinguished by the absence of 

 annulations on the shell-surface, and it is either smooth or 

 striated transversely. In Tentaculites the shell-wall is, as a rule, 

 much thicker, although some species have quite a tbin shell, as, 

 for example, that now described under tiie name of T. 

 matlockiensis. 



The species of Hyolitlies described in this paper belong to the 

 genus in its restricted sense; that is to say they have the margin 

 of the flattened side of the shell projecting considerably beyond 

 the opposite wall. 



