UPPER CAMBRIAN. 

52 
one Reference to McCoy’s 
carats Synopsis: and Figures of Genera. 
Gk Phacops (A caste). Phacops, 
Gk | PL 14, figs. 17—19, p. 162. 
Gk Pl. 1 G, figs. 12—14, p. 159. 
Gk | Odontochile truncato-caudata. 
Pl. 1G figs. 20, 21, p. 162. 
Gk Chasmops Odini ? 



Names and References; Observations, &c. 
Numbers and Localities. 


Pl. 1 G, figs. 22, 23, p. 164. 



of the species, well developed large eyes, 
11 body segments, and a lobed glabella, 
broadest in front. It ranges through all 
countries, and its vertical distribution is 
very great. Beginning in Lower Bala, it 
reaches to the upper Devonian—the latest 
known species being in the Barnstaple or 
uppermost group. 
Acaste, Chasmops, 
Odontochile, 
Crypheus, are subgenera. 
Phacops (Acaste) apiculatus, Salter (Siluria, 
4th ed. 1867, p. 69, fig. 14, woodcut, f. 3). 
A small form, much like the P. Downingie 
of the Wenlock rocks. 
Phacops (Acaste) alifrons, Salter (Mon. Brit. 
Trilob. 1864, pl. 1, figs. 31—34). A peculiar 
convex form, very like P. sclerops of Sweden. 
The glabella runs out above laterally into 
the cheeks—hence the name. 
Phacops (Chasmops) macroura, Sjégren (Mon. 
Brit. Tril. 1864, pl. 4, figs. 1S—23). A large 
trilobite (called Cat’s Head trilobite) very 
common in all the Middle Bala rocks. The 
peculiar visage of the head is given by the 
swelling of the upper glabella lobes, and 
contraction of the lower. 
[Two or three of these species used to be con- 
founded under the name P. Odini, Eich- 
wald]. 
Phacops (Chasmops) conophthalmus, Beck.? 
(Mon. Brit. Trl. 1864, pl. 4, figs. 24, 25). 
This has a wider glabella and a much shorter 
tail than the other species. 
Calymene, Brongniart. Scarce less widely 
spread, but not quite so long-lived as Phacops. 
It has a very compact form—but 13 body 
segments, and a lobed glabella which is 
smallest in front. The eye was soft, and 
is seldom preserved. The species are many, 
and not easy of distinction. 

b. 196, Pwllheli; Bala ; 
Glyn Ceiriog; Conway 
River; Llanwyddyn; Rhiw- 
argor; Rother Bridge ? 
b.198, Capel Garmon; Glyn 
Diffwys; Bala; Wilfa, Pen- 
machno; Meifod. 
a. 131, Grug, Llandeilo; 
Blaen-y-cwm, Nantyr; 
Coniston; Applethwaite 
Common. 
Alt-yr-Anker, Meifod; 
a. 128, Llansantfraid, Glyn 
Ceiriog. 
