726 



DR R. H. TRAQUAIR ON 



1896, I briefly expressed the opinion that the affinities of Drepanaspis lay rather with 

 the Pteraspidse (Nature, vol. liv. p. 263). 



To this opinion I adhered in my first detailed account of Drepanaspis, which was 

 included in my Report on the Silurian fishes of Scotland published by the Royal Society 

 of Edinburgh in December 1899. In that memoir I instituted the family Drepanaspidse, 

 and included it in the Heterostraci along with the Coelolepidse, Psammosteidae, and 

 Pteraspidse. 



In April 1900 I published in the Geological Magazine a paper entitled " Notes 

 on Drepanaspis Gemiinde?iensis," illustrated by an amended restoration of the dorsal 



Fig. 1. — Drepanaspis Gemundenensis, Schliiter ; restored outline of the dorsal aspect; the surface ornament 

 omitted, and the tail twisted round so as to show the caudal fin in profile, m.d. , median dorsal plate; 

 p.L, posterolateral plates ; r., rostral plates. 



aspect, to which I now added one showing the form and arrangement of the plates on 

 the ventral surface. Fresh material having, however, shown that the position of the 

 sensory openings was still not quite correct, I again in 1902 published in the same 

 journal some " Additional Notes " on the same creature, accompanied by restored figures 

 properly amended as regards the point in question, though the form and arrangement 

 of the scales on the sides of the tail still left something to be desired. 



Description. — Nearly entire specimens are shown in PL I. fig. 1, PI. II., and PL IV., 

 while in text-figures 1 and 3 I have given restorations of the dorsal and ventral surfaces 

 respectively. The carapace is broad, depressed, very obtusely rounded in front, and 



