178 DR G. W. LEE ON 



Comparison with other species is difficult, since it is very small and there is 

 nothino- to indicate the stage of growth of the specimen, but in many respects it bears 

 a general resemblance to Orthonychia uncum (Meek and Worthen), # a species which 

 American palaeontologists consider to be a synonym of Orthonychia acutirostris 

 (Hall).t 



Class CRUSTACEA. 



Trilobita. 



Genus Phillipsia Portlock. 



Phillipsia eichwaldi ? (Fischer de Waldheim). 

 Woodward, Monograph of the British Carboniferous Trilobita, 1883, p. 22, pi. iv. 



A pygidium and a fragment of the head, seen from the under side, are possibly 

 referable to this species. The under side of head is very much like that figured by 

 Dr H. Woodward (loc. cit., fig. 8). 



I am indebted to Dr B. N. Peach, F.R.S., for helping me in this determination. 



The following are generically indeterminable, on account of their imperfect 

 preservation : — 



Sp. a. 



A fragment of pygidium characterised by the extreme convexity of the axis and 

 the corrugated appearance of the somites, as obtains, for instance, in Griffithides 

 globiceps (Phillips). 



Sp. b. (PL II. figs. 50, 50a.) 



A fragmentary pygidium, to which are attached three axial thoracic somites. 

 Only the axis, consisting of fourteen somites, and a few of the pleural segments are 

 preserved. 



The three anterior axial rings of the pygidium are ornamented, on their median 

 portion, by a single row of strong tubercles ; laterally, these tubercles are smaller and 

 disposed in a double row. On the other rings the tubercles are in one row on the whole 

 surface, and on every third ring the central tubercle is much more prominent than those 

 next to it. The pleural segments are less numerous but broader than the axial rings, 

 and are separated by wide and deep sulci. Each segment is longitudinally divided by 

 a well-defined furrow in two sub-equal ridges, of which the anterior one is the broader ; 

 both are ornamented by a row of closely set tubercles. 



The fragments of thoracic segments are quite smooth, and are well defined. 



The specimen is too poorly preserved to permit of any suggestion as to its 



* Geol. Survey Illinois, vol. v. 1873, pi xvi. fig. 1. 

 t Geol. Survey Iowa, 1858, pi. xxiii. fig. 14. 



