Description of Genera and Species. 67 



Specimens agreeing in most respects with the present variety are not uncommon in 

 the Langholm scorpion-bed, but they are very poorly preserved. None of the 

 elongated forms, however, occur among them. It is therefore possible that the 

 Langholm form may represent a separate species, especially as the Langholm scorpion- 

 bed occupies a much higher horizon than that from which the parent species was 

 unearthed, the interval that separates them probably representing a long lapse of 

 time. For lack of better-preserved specimens, they are provisionally placed under 

 this variety. 



Locality. — Same as last ; also Scorpion-bed, Glencartholm, near Langholm. 



Horizon. — Calciferous Sandstone Series. 



Collector. — A. Macconochie. 



Antiiracoi'Iiausia TRAQUAiai (B. N. Peach). PL X., figs. 1-5. 



1882. AnthrapaUemon traquah-ii B. N. Peach, Trans. Koy. Soc. Edin., vol. 

 XXX., p. 80, pi. X., figs. 5a-5e. 



Remarks. — After the publication of the description of tlie present species in 188"2, 

 and immediately following upon the publication of the lieport on the Challenger 

 Schizopods by G. O. Sars, the well-preserved specimens of the type species of this 

 genus were discovered by Mr. Macconochie. On studying them, it became apparent to 

 me that I had made a great mistake in my original description of the present species, 

 and that I had figured two quite different types of Scliizopods under the name of 

 Antlirapalcemon tra(piairii. Fig. 5 ot my origmal description belongs to a member 

 of the newly-erected family of tlie Perimecturidir,, while all the other figures represent 

 a large species of the present Euphausiid genus, for whicli 1 retain the specific name. 

 It therefore becomes necessary to give a general description of the species, although 

 very little fresh material has been collected. 



General Descri/iflon. — The body is large, measuring 80-1(10 mm. in length, and 

 correspondingly stout ; it is laterally flattened, prawn-like, and fossilises sideways The 

 test is thin and smooth. 



The trunk, counting from the tip <.>( the long carapace, is nearly half the length of 

 the body. The carapace, seen sideways, is short, triangular, and nearly equilateral, and 

 produced into a rostrum as long as any side of the triangle. The rostrum is narrow 

 and straight at first, and then bends downwards near its anterior end. It is of bayonet- 

 form, having a decided crestal keel as well as lateral ones. There appears to be both 



