CRUSTACEA. 81 



the cephala which agree in all respects with the originals of Lichas pustuhi 

 are the only parts of Lichas yet found at this locality. The pygidium represeni 

 on plate lxxviii. fig. 7. of the Third Volume of the Palaeontology of New York, 

 upon more careful scrutiny and removal of adhering rock, proves not to 

 have the hilobed caudal margin as there illustrated, and its proper character is 

 shown on plate xix, fig. '•*: the margin bearing three pair- of lateral lobes, 

 much narrower than in L. pustulosus, and terminating in a single, moderately 

 broad posterior lobe. The single specimen showing this form of pygidium 

 is from Schoharie, from which locality are also the large pygidia originally 

 referred to Lichas pustulosus. 



The cephalic portions of Lichas Bigsbyi are known only from the Lower 

 Pentamerus limestone at localities in Schoharie county. It is impossible, how- 

 ever, to say which of the three different forms of pygidia represented on plate 

 xix, fig. 9, plate lxxvii. fig. 8 (pp. cit.), plate lxxviii, figs. 1. 5 (op. cit.), and plate 

 xix a, fig. 1. is to be referred to this species. These cephala are not of uncom- 

 mon occurrence, and by far the most abundant of the pygidia are those figured 

 on the last two plates cited, the other two forms occurring, so far a- known, 

 only in single examples. It is therefore probable that the large pygidia hear- 

 ing three pairs of lateral spines and a pair of posterior spines belong to the 

 species Lichas Bigsbyi. 



[s.-g.] HOPLOLICHAS, Dames. 1877. 

 Lichas (Hoplolichas) htl^us, n. sp. 



PLATE XIXB, FIGS. I. 2. 



The intra-sutural portion only of the ceph.vlon has been observed. Outline 

 semi-elliptical; surface strongby convex, tumid along the axial line, abruptly 

 deflected to the margins. 



Glabella large, sub-pentagonal. Frontal lobe elongate-pyriforra or clavate, 

 widest ami most convex anteriorly, narrowing and becoming depre 

 medialby, and abruptly widening again at the occipital furrow. The second 

 pair of transverse furrows is obsolete, the first and second pairs of glabellar 



