648 SILURIAN TRILOBITES OF NEW SOUTH AVALES, V., 



Salter, had he been famiUar with the latter genus. It must not 

 be forgotten, however, that as Salter's memoir was published in 

 1853, and Barrande's description of Cromus only appeared in 

 1852, it is quite probable the English Palaeontologist was unaware 

 of his French colleague's labours. 



We know of no more instructive and complete figures of Encri- 

 witrus 2^u7ictatus than those by Mr. E. Hoffmann,"^ of specimens 

 from the Island of Oesel, in the Baltic. Herein are shown the 

 course of the facial sutures on the front of the glabella centre, 

 the peduncular eyes, and the characteristic granulation of the 

 pygidium. 



On the other hand, an equally good illustration of a non- 

 testiferous example is that of Hawle & Corda's generic figure.! 

 Here are shown the large marginal tubercles along the axial 

 furrows of the glabella, and when in this condition, the spaces 

 between them simulate very short lateral glabella furrows; but, 

 as a matter of fact, this simulation is only produced by the pro- 

 jection of the tubercles in question. Similar features are shown 

 in Angelin's figure of E. jninctatni^. % 



Barrande's enumeration of Cromiifi appeared in his monu- 

 mental work "Systeme Silurien du Centre de la Boheme."v5 



In general features, Cromus resembles Encrinnrus, particu- 

 larly in the form of the thoracic segments, test-ornamentation, 

 outline of the pygidium, etc. On the contrary, the glabella bears 

 four pairs of distinct lateral furrows, the hypostome lacks the 

 forward prolongation of that of Enarirmrus, the eyes are sessile, 

 poorly developed, and, so far as known, there are but ten seg- 

 ments in the thorax as against eleven in that of Encrinitrus. 



It is perhaps worthy of remark that Zittel, in his "Handbuch 

 der Palseontologie,"!! retained Encrinurus and Cromus as distinct 



* Hoffinann, Verhandl. Rus.-Kaierl. Min. Gesellsehaft. St. Petersburg, 

 1857-58(1858), PI. iii., fig.5a. 



t Hawle & Corda, loc. cit., PI. v., fig. 55. 

 i^lAngelin, Pal. Scandinavica, 1878, Pt.l, PI. iv., fig. 4 (as Cryptonymui 

 punctatus). 



§!., 1852, p. 821. 

 II Zittel, i., Abh., ii. Rand, p.621. 



