﻿ASAPIIIDyE. 



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H. annatus, Burm., from the Lower Devonian of Germany, hardly needs comparison, 

 as it has a minute tail for the size, with but a single lateral spinous tubercle. The 

 species figured, but without a name, by Steiningcr in the 'Mem. Soc. Geol. Prance,' 

 vol. i, pi. xxi, fig. 8, has a large spinous tubercle on the first and fifth lateral ribs ; 

 but the tail is truly triangular. I think that probably this species does occur in the 

 German Devonian ; and that there is a fragment of it in the Geol. Soc. Museum from 

 the Rhine Provinces, (marked as from the Eifelj Drawer 40) ; but I cannot identify it 

 with any of the published forms. 



Locality. — Lower Devonian ; Meadsfoot Sands, S. Devon. (Mr. Hall's cabinet). 



Family — ASAPHID.E, Emmrich, 1S39 (?). 



If the Calyncnidce are but a small group, the Asaphidce are at present an unwieldy 

 one. This is to a great extent a natural family, and I am unwilling to divide it ; 

 though we may well distinguish in it several sub-groups, hereafter, perhaps, to be called 

 families — Oyyyidcs, Asajrfudes, Illanides, jEylinides, &c. 



Taken as a whole, the Asapliidce comprehend the most bulky and expanded forms of 

 the Trilobite family, together with some which are of much less stature. The head and 

 tail are in general of great comparative size, the latter often free from visible segments, 

 though really composed of many. The thorax is reduced in size, and generally of eight 

 segments, but not always — for instance, Illcenus and Styyina. Respecting JEylina, which 

 lias only six rings, and which genus I have kept apart in the preliminary sketch, p. 2, 

 there may be reason to suspect it to belong to a distinct family when we know more of 

 its relations. We must exclude it from the character of the family, which, as above said, 

 has in general eight, more rarely nine or ten, body-rings. 



Taking the general characteristics, we may say that the AsapJiida are — Large 

 Trilobites, generally of an oval form, without any ornaments except a close striation (which 

 is -very common), and totally destitute of tubercles or spines on the surface. The head 

 and tail are large and well developed, and the former has usually an obscure glabella, 

 with but indistinct lobes. Yet in this family we have Trilobites possessing distinctly 

 four lateral lobes to the glabella, Oyyyia, Barrandia, and Niobe having that number. 



The facial sutures end on the posterior margin. The eyes are smooth and large ; 

 occasionally, but rarely, very prominent (Asajj/aes) ; usually conical or even depressed 

 {Illcenus, Oyyyia?) &c. The head-angles are more often obtuse than spinous, and never 

 greatly prolonged. 



The thorax of eight rings (rarely more, as in Ulanus and Styyina), always facetted, 

 and, with few exceptions, grooved throughout : the apices blunt, or only shortly pointed. 

 The large tail is of many segments, and there is every gradation in it from a flat 



