Case and | 
Column of 
Drawers. 
Gh 
Gh 
Gh 
Gh 
Gh 
Gh 
Gh 

| “facial suture” 
Reference to McCoy’s 

Synopsis: and Figures of Genera. 
Trilobites. 
A gnostus. 
[Rudimentary trilobites, 
with few segments to the 
thorax. 
| these early forms. ] 
Microdiscus. 

The characteristic | 
is. absent in | 
| Agnostus scutalis, 
MIDDLE CAMBRIAN. 

Names and References; Observations, &e. 
CRUSTACEA Trilobita. 
Agnostus princeps, Salter (Quart. Geol. Journ. 
Vol. xx. pl. 13, fig. 8). A species of long 
range in the Lingula flag. The genus is the 
simplest and most rudimentary of all Trilo- 
bite forms. Only 2 segments to the body. 
_ Agnostus, sp. Convex, lobeless, like A. bibul- 
latus, Barr. 
Agnostus Davidis, id. (Reports Brit. Assoc. 
1865. Trans. Sect.) One of the largest 
species. Equal in size to A. aculeatus, Ange- 
lin, but remarkably even and slightly lobed. 
Agnostus scarabeoides, Hicks. Surface wholly 
granular. 
_ Agnostus cambrensis, Hicks. Allied to A. in- 
teger of Bohemia. 
_Agnostus acumensis, Hicks, and A. lagena 
are new forms. 
Salter. Resembles A. pisi- 
JSormis, Linn. from Sweden. 
Agnostus Barrandii, Hicks. Smooth, convex, 
head-lobes incomplete. Resembles A. levi- 
gatus of Sweden. 
Agnostus Eskriggi, Hicks. 
Agnostus reticulatus, Ang. Pal. Suec. The limb 
is deeply and largely reticulated. 
collections this appears as A. nodosus, Belt.) 
| Microdiscus punctatus, Salter (Quart. Geol. 
Journ. Vol. xx. pl. 13, fig. 11). A minute 
form, shewing 4 body segments. Otherwise 
it has the characters of Agnostus, and like 
it is blind, and has no facial suture. 

_ Holocephalina primordialis, Salter (ib. fig. 9). 
A very simple type of many-ringed trilo- 
bites allied to Arionellus, which is a Bohe- 
mian and Spanish form. It has minute ex- 
ternal eyes, and the facial suture only cuts 
off the extreme spinous angle. 
Numbers and Localities. 

a. 4, Maentwrog waterfall. 
| (Mr. Ash.) b. 273, do. (D. 
Homfray). a. 255, Cwm 
| heisian, Gold mines, Dol- 
gelly. (Mr. Plant, 1869.) 
b. 266, Gwynfynydd, Dol- 
gelly Gold mines. (Mr. D. 
Homfray.) 
St. David’s. (Dr. Hicks.) 
a. 254, Cwm heisian; Mr. 
Plant. bv 27s Rhaide ddu 
valley, Maentwrog. (Mr. 
D. Homfray.) 
[St. David’s.] Dr. Hicks’ 
cabinet. 
[St. David's. ] do. 
| [St. David’s. | do. 
St. David’s. do. 
(In some | 


| a. 288, St. David’s. 
| Dr. 
b. 265, b. 274, Lower beds, 
St. David's. (D. Homfray.) 
[St. David’s.] Dr. Hicks’ 
| cabinet. 
b. 267, b. 272, Tyn-y-groes. 
on the Mawddach River. 
(Mr. Homfray.) 
St. David’s. (Dr. Hicks.) 
a. 253, Tyddyngwladis. (Mr. 
Plant.)  b. 275, Tafarn 
Helig, S. of Ffestiniog, N. 
Wales. (Mr. D. Homfray.) 
(Pres. 
Hicks; and cast of 
figured specimen, by J. W. 
Salter.) b. 304, Maentwrog 
waterfall valley, or Tafarn 
Helig, Ftestmiog. (Pres. 
by D. Homfray.) 
