BY R. ETHERIDGB, JUNR., AND JOHN MITCHELL. 719 



Ceratocephala Vogdesi, E. and M. 



Fig. S.— Portion of a cephalon, with the right genal spine preserved and 

 the right occipital spine indicated ( x 2). Coll. Mitchell. 



Fig. 9. — Bispinate distal end of a thoracic pleura, the spines barbed; 

 slightly enlarged. Coll. Mitchell. 



Plate LI. 

 Ceratocephala Vogdesi, E. and M. 



Fig 1. — Portion of a thorax showing the peculiar distal termination of 

 the axial segments, tubercles of the pleurae, and lai-ge and 

 strong spines of the latter; somewhat reduced. Coll. Austra- 

 lian Museum, Sydney. 



Fig. 2. — Portion of anotlier thorax exhibiting the bispinate character of 

 the distal ends of the pleurte; somewhat reduced. Coll. Mitchell. 



Fig. .3. — Cephalon showing the nature of the genal and occipital spines 

 and position of the eyes; sliglitly reduced. Coll. Mitchell. 



Fig. 4. — The last thoracic segment with its perpendicular spines; slightly 

 reduced. CoU. Mitchell. 



Fig. 5. — Pygidium with its barbed spines; slightly reduced. Coll. Mitchell. 



Fig. 6. — A principal tubercle from one of the pleura3 of fig. 1; highly 

 magnified. 



Fig. 7. — A principal tubercle from a similar position on fig. 2; highly 

 magnified. 



Odontopleura Eattei, E. and M. 



Fig. 8. — Glabella without the side lobes, showing granulation and occipital 



tubercle; slightly enlarged. Coll. Mitchell. 

 Fig. 9. — Free cheeks; somewhat enlarged. Coll. Mitchell. 



Plate LIT. 



Odontopleura Rattei, E. and M. 



Fig. 1. — A nearly complete specimen ( x 2^). Coll. Mitchell. 



Fig. 2. — A cephalon without the free cheeks, &c. (x 2|). Coll. Mitchell. 



Fig. 3. — The pygidium with strongly developed spines ( x 3). Coll. 



Mitchell. 

 Fig. 4. — Portion of the two posterior thoracic segments, and the pygidium 



( X 21). Coll. Mitchell. 



Odontopleura bowningen,sis, E. and M. 



Fig. 5. — The four posterior thoracic segments and the pygidiunr (x2i). 

 Coll. Mitchell. 



