720 SILURIAN TRILOBITES, 



Odontofleuka Jenkinsi, E. and Jf. 



Fig. 6. — Portion of the lliorax and pygidium showing very distinctly 

 granulation on tlie pleural ridges; slightly enlarged. Coll. 

 Mitrhtll. 



Fig. 7. — Pygidiiun only, showing pleural ridges and their granulation: 

 slightly enlarged. Coll. Mitchell. 



Odontopleura parvi.ssima, E. and M. 



Fig. S. — Free cheek with genal and marginal spines, and eye ( x ,3). CoU. 

 Mitchell. 



Plate Liii. 



Odontopleura Rattei, E. and M. 



Fig. 1. — Cast from an impression of an almost perfect individual; spines 



of pygidium incorrectly shown; somewhat enlarged. Coll. 



Mitchell. 

 Fig. 2. — Thorax and pygidium, the two anterior segments of the formei- 



devoid of pleural spines; somewhat enlarged. Coll. Geol. 



Survey Queensland, Brisbane. 

 Fig. 3. — Free cheek; slightly enlarged. Coll. Mitchell. 



Odoxtopleura Jenkinsi, E. and M. 



Fig. 4. — An almost complete example, with a single series of tubercles on 

 either side; somewhat enlarged. Coll. Mitchell. 



Fig. 5.— Three thoracic segments with from two to three rows in a similar 

 position; somewhat enlarged. Coll. Mitchell. 



Fig. 6. — Glabella with its lateral lobes and extensions of the neck ring 

 and one free cheek; slightly enlarged. Coll. Mitchell. 



Fig. 7. — A second glabella; slightly enlarged. Coll. Mitchell. 



Ceratocephala Jackii, E. and M. 



Fig. S. — Impression of the cephalon; slightly enlarged. Coll. Geol. Survey 

 Queensland, Brisbane. 



Ceratocephala Vogdesx, E. and Jf: 

 Fig. 9. — Pygidium with its large dentate spines; somewhat enlarged. Coll. 

 Mitchell. 



CerjVtocephala longispina, Mitchell, sp. 

 Fig. 10. — Pygidium with its axial spines; somewhat enlarged. Coll. Mitchell. 



Ceratocephala impedita, E. and M. 

 Fig. 11. — Portion of the cephalon, showing glabella, side lobes and bases 

 of occipital spines; slightly enlarged. Coll. Mitchell. 



