66 Description of Genera and Species. 



embedded are near the base of the Cementstone Group (Tuedian) of the Merse of 

 Berwicksliire, and not far above the horizon of the Kelso Volcanic Plateau. The 

 Langholm scorpion-bed, which has yielded such a large suite of well preserved 

 Schizopods and other crustaceans, often with the gut distended, is interbedded in a 

 volcanic series at a higher horizon in the Calciferous Sandstone Series, while the bed 

 of shale at GuUane, on the shores of the Firth of Forth in Haddingtonshire, on a 

 corresponding horizon and connected with the great volcanic plateau of the Garleton 

 Hills, has yielded an abundance of almost perfectly-preserved specimens of the genus 

 Tealliocaris. Beds of fine ash are intercalated in the Wardie Shales at about the same 

 horizon. In all these cases the beds that have yielded the crustaceans in shoals in the 

 same layer have also yielded whole fishes often in great abundance. It looks as if 

 the constant association of these beds, richly charged with nearly perfect remains of 

 such fragile creatures, with volcanic conditions, were more than a coincidence, and 

 that the waters were periodically poisoned by volcanic gases, so that both the crusta- 

 ceans and their natural enemies the fishes met a common fate ; otherwise it is difficult 

 to conceive that the fishes would not have preyed upon the dead Ijefore their entomb- 

 ment. The attitudes assumed in dying by some of the fishes and the Crustacea have 

 already suggested the same idea. 



The specific name is derived from Duns, Berwickshire, near which the fossils 

 were obtained. 



Locality. — Whiteadder Water, near Duns, Berwickshire. 



Horizon. — Near base of Cementstone Group (" Tuedian "), (Scottish) Calciferous 

 Sandstone Series. 



Collector. — A. Macconochie. 



Anthracophausia dunsiana, var. obesa var. nov. PI. IX., figs. 11-15. 



Remarks. — Among the numerous remains of this species from this locality there 

 is a considerable range in form. As has been already stated, the females are more 

 massively built than the males, but there is a greater variation than can be accounted 

 for by sex. For instance, fig. 11 is undoubtedly that of a male in which not only is 

 the body altogether stouter, but there is a considerable difference in the proportions of 

 the carapace, which is shorter and much deeper in proportion to its length. The 

 rostrum is also shorter and more curved, and the peduncles of the autennte seem to be 

 much more massive. Fig. 12 shows what is probably a female of this variety in which 

 the luminous organs on the tail segments are indicated through the integuments. 



