231 
DESCRIPTION OF THE FOSSILS. 
1. lobe. s. sinus. <r. the siphuncle, which is not a continuous tube but passes 
retrally from the septal plate a short distance. As an example, the septum of G. striatus 
may be thus marked and described. Dorsal lobe (D. Z.) bifid, dorsal sinus (D. ,y.) 
acute ; first lateral lobe (L, l'.) acute, twice as long as the dorsal lobe, second 
lateral lobe (L. Z".) obtusely rounded, shorter than the first; marginal sinus (M. s.) 
angular. 
G. sphaericus. (Aram, sphasricus, Sow.) PI. XIX. fig. 4. 5, 6. Derby- 
shire ; Bolland ; Isle of Man ; and Kildare County. 
More globose than the preceding ; shell spirally striated, with (variable) internal 
ridges ; septa as in the preceding, except that the first lateral lobe is less acute, or even 
rounded ; it grows twice as large. 6. From a Bolland specimen. 
G. crenistria. Ph, PI. XIX. fig. 7, 8, 9. Bolland ; Queen’s County ; 
Fermanagh ; Isle of Man. 
Subglobose, umbilicus very small, rounded ; shell with fine crenulated, reticulated, 
bent, transverse striae. These are magnified at fig. 8. Some varieties are more globular 
than the figure. Septa as in the preceding. 
G. obtusus. Ph. PL XIX. fig. 10 — 13. Black Hall in Bolland. 
Subglobose, with flatfish sides, and broad back : umbilicus very small, shell with 
delicate transverse and a few longitudinal stria*, and internal slightly bent ridges ; edge 
of the septa delicately marked and waved, dorsal lobe very short, dorsal sinuses acute, 
first lateral lobe rounded. 
G. striolatus. Ph. PI. XIX. fig. 14—19. In shale, Kulkeagli ; near 
Enniskillen ; in shale, High-Green-wood, near Todmorden. 
Almost exactly similar to G. obtusus, but the sides less parallel : striae very delicate ; 
septa fig. 18, with very wide pointed dorsal sinuses, and very wide rounded lateral lobes. 
The adult shell almost exactly resembles XIX. 12 ; the series of younger forms may be 
seen by fig. 15, 16, 17- The very young shells are more globular, with a large acute 
edged umbilicus, straight constrictions, and straight delicate simple striae. With age the 
shell flattens, the constrictions become slightly waved and then cease entirely, the um- 
bilicus loses its angularity ; the septa and striae scarcely vary ; — my Kulkeagh specimen 
has the dorsal sinuses, fig. 19, rather less wide, and its outline differs a little. 
G. truncatus. Ph. PL XIX. fig. 20, 21. Bolland. 
Very depressed, back (in adults) truncate ; umbilicus open ; fine transverse bent 
striae. The outline of the mouth appears in fig 14. 
G. foraminosus. Ph. Bolland. 
Depressed, spirally striated, umbilicus Very small. 
G. micronotus. Ph. PL XIX. fig. 22, 23. Bolland. 
Depressed, umbilicus small, rounded, striae transverse, constrictions little bent ; septa 
with dorsal lobe small, first lateral lobes large and rounded, their dorsal edges parallel. 
