Cypliaspis spryi, a neiv species of Trilohite. 181 



the size of the genal spines and the shape of the glabella ; but the 

 glabella is not granulate, the spines are less outwardly directed, 

 and there is no dorsal spine as in one sex of C. howningensis. 

 There is moreover no trace of the anterior furrow which, as 

 Etheridge and Mitchell suggest, render the New South Wales 

 form a possible ally of Phaetonides. 



Among European trilobites the nearest species is C. burmeisterp- 

 or C. halli{- both of which come fi'om the lower part of the 

 Silurian (syn. Upper Silurian); amongst other specific differences 

 C. halli has 17 thoracic segments and 4 ridges on the pygidium ; 

 and C. hurmeisteri has 8 ridges on the pygidium and from 1 1 to 

 15 thoracic segments and no azygous cephalic spine. 



The precise age of C. spryi^ must be left for the present some- 

 what uncertain. Its nearest European allies C. halli and C. 

 burmeisteri both come from Barrande's stage E or the lower part 

 of the Silurian {i.e. of the Upper Silurian of the Victorian 

 Geological Survey). Amongst other fossils found with C. spryi 

 is the hinder end of a Homalonotus which is almost identical with 

 H. harriso?ii, M'Coyf there is one slight difference. In If. 

 harrisofii, according to M'Coy, the sulcus is along the middle line 

 of the thoracic segments, whereas, in the specimen found by Mr. 

 Spry, the sulcus is posterior in position. This difference may 

 possibly be specific ; the South Yarra Hotnalonotus cannot be 

 satisfactorily determined until the cephalic shield be discovered. 

 But the occurrence of this H. aff, harrisoni with the C. spryi is 

 in favour of the South Yarra beds being low in the Silurian 

 system, for INI 'Coy originally assigned the former species to the 

 Llandovery series. 



On the other hand a somewhat later date for this horizon is 

 suggested by the occurrence of Hapalocrinus vicioriae, Bath., with 

 the C. spryi ; for according to Bather,* Hapalocrijius ranges from 

 the Middle Silurian to the Lower Devonian. 



1 Barrande. Systeme Silurien du Centre de la Boheme, p. 484, pi. xviii., fig. 61-71 and 

 1846. Not. pr^l. p. 59. 



2 Barrande. Systeme .Silurien du Centre de la Bohtme, pt. i. (1S52), p. 483, pi. xviii., fiy. 

 35-37. 



3 M'Coy. Prod. Pal. Vict. Dee. iii. (1876), p. 19, pi. xxiii., fig. 11. 

 4 Bather. Geol. JIag., Dec. iv., vol. ix. (1S97), p. 345. 



