234 TRANSACTIONS OF THE [may 18, 
forfax of Broegger, which also has the pygidial axis thus defined; 
but this axis in the Norwegian variety is longer and is not di- 
vided into lobes. In var. ferranvvicus the front lobe of the 
pygidium is separated by a furrow from the rest of the rachis, 
but there is no middle lobe except in so far as it is indicated by 
a tubercle about one-third from the front. The side lobes of the 
pygidium are wider than in var. forfax. 
Sculpture.—The test is minutely punctate. 
Size.—Length and breadth of each shield,5 mm. Rachis of 
pygidium, 4 mm. long, 2mm. wide. 
Horizon and Locality.—Dark siliceous slate of Highland 
Cove, Trinity Bay, Newfoundland, with P. Davidis. 
Var. CICEROIDES n. var. Plate xvii., fig. 3 a and b. 
This is a smaller and more tumid form than the preceding, 
and the rachis of the pygidium is wider in proportion; the mid- 
dle lobe of the rachis is marked off from the posterior by a 
faintly impressed line, and bears a more prominent tubercle than 
the preceding variety. 
Sculpture.—As the preceding. 
Size.—Length and width of each shield, 34 mm. Rachis of 
pygidium, 24 mm. long, 14 mm. wide. 
Horizon and Locality.—Found with the preceding. 
The head shield of this variety is like that of A. Cicer, Tull- 
berg, but it is furnished with a marginal fold; that species also 
has a wider and only partially defined rachis to the pygidium. 
Var. MAMILLA, n. var. Plate xvii., figs. 3 a and 0. 
Nearly the same size as the preceding. It has more distinct 
basal lobes, but the difference is chiefly in the pygidium ; the 
rachis is undivided and greaty elevated at the second somite 
where there is a prominent tubercle one-third from the front of 
the rachis; the lateral lobes are divided by a furrow, and the 
posterior marginal fold is wide. 
Sculpture.—As the preceding but with small scattered tuber- 
cles on the head shield. 
Size—Length and breadth of the shields, nearly 4 mm. 
Rachis of the pygidium: length, 24+-mm.; width, 14+mm. 
Horizon and Locality.—Found with the preceding. 
While the head of this variety is that of a Levigatus, the pygi- 
dium is nearly that of a Parvifrons; in the latter, however, the 
dorsal and marginal furrows of the pygidium are confluent, in 
this variety they are distinct, but connected by a cross-furrow. 
But for the absence of glabella this variety would closely re- 
semble Broegger’s var. mamillatus of A. parvifrons. 
