Crustacea. | DEVONIAN ARTICULATA. 177 
Sect. V.—ARTICULATA OF MIDDLE PALAZOZOIC (DEVONIAN) ROCKS. 
Sub-kingdom. ARTICULATA. See page 127. 
Class. CRUSTACEA. See page 133. 
Tribe. PHYLLOPODA. See page 134. 
Family. TRILOBITIDA. See page 138. 
Genus. PORTLOCKIA (MCoy). See page 162. 
PoRTLOCKIA GRANULATA (Miinst. sp.) 
Syn. and Ref.—Calymene id. Miinster, Beitrage, t. 5. f. 3. Phill. Pal. Foss, f. 248. 
Sp. Ch.—Cephalic shield semicircular, the sides much bent downwards; glabella large, tumid, widely 
pyriform or subdeltoid, slightly pointed in front, greatest width usually exceeding its length including the 
neck-segment, sides rapidly converging to the base, which is scarcely half the width of the front; two 
deep punctures at each end of the deep neck-furrow, (but no trace on inner or outer surfaces of anterior 
segmental furrows); checks of moderate size, with a strong border overhung by the glabella in front; 
eyes very large, reniform, of about thirty-seven coarse lenses (five in one line); swxface of cheeks and 
glabella covered with small, irregular granules, smaller than the lenses of the eyes but not so close (four 
in one line); length three lines, width in a direct line six lines; pygidiwm semicircular, averaging two 
lines long and four lines wide, with a flattened margin half a line wide; mesial lobe narrow, prominent, of 
nine or ten obscurely tuberculated rings, lateral lobes with about eight strong ribs each divided by a fine 
pleural furrow. 
The smaller size of the granulation easily separates this from the P. /atifrons; and the absence on the 
casts of the fine anterior segmental furrows separates it from the Silurian P. Stokes’, as well as the more 
pointed front of the glabella, and fewer lenses to the eye from the encroachment of the larger eye-lobe. 
In the Silurian species the eye-lenses are about fifty, and seven occupy the space of one line. 
Position and Locality—Very abundant in the soft decomposing schists of Petherwin, Cornwall. 
PORTLOCKIA LATIFRONS (Bronn sp.) 
Ref. and Syn.— Culymene latifrons (Bronn) Leth. Geog. t. 9. f. 4.= Calymene Latreillii (Stein.) Phill. Pal. 
Foss. t. 56. f. 249, and ©. accipitrina Phill. (name only) Pal. Foss. bottom of p. 128. 
Sp. Ch.—Cephalic shield semicircular, sides much deflected, lateral angles obtusely rounded ; glabella 
tumid, depressed, pyriform, or obscurely angulated in front, width equal to its length including the strong 
Aa 
