BY JOHN MITCHELL. 449 



ffausmannia (Dalmanites) meridianus E. & M. 

 Fix..'}. — The photo of the original type specimen of Hawmannia meridianus 

 E. & M,; contrasting this with fig. 1 of this Plate, the differences 

 between the two species will be very evident. ( x h nearly). 

 Fig. 4. — A pygidium showing 12 pleural segments and the extension of the 

 axis into the spine, (xj). (Coll. Mitchell). 

 Phacops crossleii E. & M. 

 Fig. 5. — An almost perfect specimen for comparison and contrast with 

 Adastocephalum teleotypicum. (x about 2). (Coll, Mitchell). 

 Phicoji* serratus E, & M. 

 Fig. 6. — A very fine specimen of a young individual given to compare and 

 contrast with Adastocephalum teleotypicum. ( x about 2). (Coll. 

 .Mitchell). 



Plate xvi. 



Adastocephalum teleotypicum Mitchell. 



Fig. 1. — Photo of the only portion of the glabella known; shows the generic 



and specific features fairly well. ( x about 2). (Coll. Mitchell). 

 Fig. 2. — The same with outline restored. 



Dalmanites loomesi Mitchell. 

 Fig. 3. — Photo representing portion of a thorax, and complete pygidium, 

 except for the removal of a part of the border. Shows the imper- 

 ceptible mergence of the thoracic axis into the pygidial axis, etc. 

 (Coll. Mitchell). 

 Fig.4. — Another photo of the same specimen shown on Plate xv., fig. 1, 



with the defective part restored (Reduced). (Coll. Mitchell), 

 Fig.o. — Side view of an eye; ( x about 3). (Coll. Mitchell). 



ffausmannia (Dalmanites j meridianus. 

 Fig.6. — Photo from a squeeze of the counterpart of a -pygidium showing 



the long acicular spine or telson; ( x2). (Coll. Mitchell). 

 Fig.7. — Pygidium of a mature individual showing twelve pleural segments 

 and their characters clearly. 



