DY R. ETHERIDGE^ JUKE.^ AND JOHK MITCHELL. 657 



Another feature we have observed is, that the cephahc axial 

 grooves anteriorly do not terminate or pass out in tlie same way 

 in all the species of our Australian Encrinuri. For instance, 

 in E. mitchelli they do not cross the anterior border of the 

 cephalon; but merely communicate with the furrows on those 

 l^ortions of the free cheeks outwaixl and laterally from them ; and 

 neither axial grooves nor free cheek furrows extend along the 

 inner and frontal portions of the free cheeks. On the other 

 hand, the axial grooves of E. Iimvnimiensis and E. silver dalensis 

 pass outward (or backward) and laterally into the free cheek 

 furrows, and alst) branch inwardly and obli(|[uely downward along 

 the frontal lobe-like portions of the free cheeks, issuing with the 

 facial sutures mediall}' in front. Another variation of the 

 anterior termination of these axial grooves (jccurs in E. dun- 

 troonensis. In this species, they communicate with the axial 

 furrows of the outward portion of the cheeks, and also turn 

 inwards and extend rather moi'e than half-way across the inner 

 lobes of the free cheeks, ending abruptly. These different varia- 

 tions of the axial grooves as they traverse the free cheeks and 

 terminate, appear to us to be of much specihc value. 



vi. DESCRIPTION OF THE SPECIES. 



Encrinurus mitchelli, Foerste. 



(PL liv., figs. 1, 2, 3, 4, 5 ; PL Iv., figs.l, 2, 3, 15; PL IvL, figs.2, 10; 

 PL Ivii., fig. 9.) 



Encrinurus mitchelli, Foemte, Bull. 8ci. Lab. Denison Univ., 1888, 



iiL, Pt.2, p.l24, PL xiii., figs.2, 3, 20. 

 i^^C ramus murchisoni, De Koninck, Foss. Pal. Nouv.-Galles du 



Sud, 1876, Pt.l, PL L, fig.9 (exclude figs, 'da and %), 

 JSp. char's."^ — Complete form subellipsoidal to some extent, with 

 a flattened appearance. Cephalon subsemicircular, length approx- 

 imately seven-sixteenths of the width between the genal angles; 

 glabella subpyriform with greatest convexity midway between 



* Where not otherwise stated, the desciiptions of all the Encriimri in 

 this paper have been made from non-testi/erous specimens. 



