THE FAUNA OF THE ST. JOHN GEOUP. iSl 



The preceding description applies to the narrow form, the broad form differs in the 

 following respects : — The anterior margin is more broadly rounded, the space in front of 

 the glabella is more than half of the length of the glabella ; the glabella is somewhat 

 wider than long, and the eyelobes are proportionately nearer to it than in the narrow form, 

 and the posterior extension of the snture is not so prominently arched ontward. 



Sculpture. — The onter surface of the test is very minutely granulate, but the inner 

 much more coarsely ; and the mould thus has a surface like that of the test of Soleno- 

 pleura. 



Length of centre-piece of head-shield of long form, 7| mm. ; width of the base of the 

 shield, 9 mm. Length of same part of the broad form, 7 mm. ; width, 8J mm. 



Locality and Horizon. — In the calcareous conglomerate at the base of the Band Ic. at 

 St. Martin's. 



Var. COMPRESSA (PI. I, figs. 1 g- to I.) 



A small form, with prominent cylindrical glabella, depressed rront, posterior angles 

 bent backward and pointed, narrow and compressed behind. This has a general resem- 

 blance to Solenopleura Robbii, var. Orestes, where perhaps, it may belong, if the dotted 

 restoration of the occipital spine is an error. 



Loculiti/ and Horizon. — With the preceding, in Div. If', (calcareous conglomerate) at St. 

 Martin's. 



This species is placed under Agraulos as the nearest genus, though when the movable 

 cheeks and other parts are known, it may be found to belong elsewhere ; it is placed here 

 on account of its long descending front, and eyelobes distant from the glabella, and 

 descending slopes all around the front and sides of the head-shield. Its stout occipital spine 

 precludes us from referring it to Ellipsocephalus, to which its descending front with mar- 

 ginal fold, tumid fixed cheeks, and short and small movable cheek ally it. The direction 

 of the furrows on the glabella also correspond to those of Ellipsocephahis. It is another 

 of those intermediate forms, whose generic place is uncertain, but without a better know- 

 ledge of the parts than we at present possess, it seems best to leave it under Agraulos. 



The posterior part of the head in this species bears considerable resemblance to that 

 of Agraulos aj/inis of the Lower Cambrian fauna of Newfoundland, but the front is quite 

 different. The narrow and the broad forms have respectively a general resemblance to 

 Arionellus primœvus and Ellipsocephalus Nordenskioldi of the Lower Paradoxides beds of 

 Andrarum in Sweden, but these are both represented as devoid of an aculeate occipital 

 ring. The horizon of these species, however, cannot be far from ours. 



This species is named in honor of Prof R. P. Whitfield, who has connected his name 

 with the fauna of the Primordial period by able articles. 



Sub-genus STRENUELLA. 



In a previous article on the Cambrian faunas of Cape Breton and Newfoundland,' the 

 writer has figured Agraulos stremius, of Billings, from the Cambrian formation in south- 



' Trans. .Roy. Soc. Can., vol. iv. p. 154. 



