566 BRITISH PALALOZOIC FOSSILS. [CerHALopopa. 
strie. Septa: mid-lobe trifid, the lobules pointed, the middle one one-fourth the length of the lateral ones ; 
Jirst sinus large, semicircularly rounded at the end, with subparallel sides, twice as long as the indentation in the 
mid-lobes ; first Zateral lobe lanceolate-acuminate at apex, as long as the mid-lobe, but rather narrower than the 
first sinus; second sinus scarcely marked, about two-thirds the length of the first sinus, coinciding with the edge 
of the umbilicus, into which its outer side extends nearly at right angles with its inner one. Diameter of 
average specimen one inch eight lines, proportional diameter of outer edge of umbilicus “, width of mouth %, 
antero-posterior diameter of mouth =. A young specimen five lines in diameter has the umbilicus “, and 
width of mouth °°. 
In yery young specimens the umbilicus is rather larger, and the tubercles or crenulations on the edges give 
rise each only to one or two transverse ridges, which are more strongly marked and more sinuous than in the 
adult, and seem in this state to coincide with the Goniatites Marianus, Murchison, Verneuil and Keyserling, 
Geol, Russ. t. 27. f.@. The substance of the shell is excessively thin, and on the exterior the fasiculate ridges 
are obscured by the transverse striz. 
Position and Locality—Not uncommon in the coal-shale of Halifax. 
. 
AGANIDES RETICULATUS (Phill. Sp.) 
Ref. and Syn.= Goniatites reticulatus Phill. Geol. York. Vol. II. t. 19. f. 26 to 32. 
A crushed fragment from the carboniferous limestone of Lowick, and two from that of the Isle of Man, 
possibly belong to this species, but shew no septa, and are too imperfect for description. 
AGANIDES SPHaRICUS (Mart. Sp.) 
Ref. and Syn.=Conch. Naut. sphericus Martin, Pet. Derb. t, 7. f.38 to5; de Kon. Anim. Foss. Bel. t. 50. f. 9. 
Dese.—Globose, subsphzeroidal, very slightly flattened towards the umbilicus, which is small, very deep, 
rounded, and exposes the edge of the inner whorls. Septa: mid-lobe trifid, narrow, the middle lobule short, 
pointed, about one-third the length of the lateral ones, which are very acutely angular ; first sinus broad, acutely 
angular, usually obtuse at the tip, and not extending quite so far forward as the centre lobule of the succeeding 
mid-lobe, about twice and half the length of the divisional sinus of the mid-lobe; first lateral lobe tongue- 
shaped, abruptly attenuated, and acutely pointed at the extremity, scarcely exceeding the mid-lobe in length, 
about equal in width to the mid-lobe at base ; second sinus obtusely rounded, not extending quite so far forward 
as the first, its outer margin extending with slight curvature into the umbilicus. Surface crossed by nearly direct, 
regular, transverse, fine, broad, flat, slightly imbricating striz, serrated on their free edge (about eight to ten 
strie in one line). Diameter of small specimen ten lines, proportional diameter of umbilicus 35, width of 
transverse reniform mouth 3, antero-posterior diameter of mouth in middle 3%. 
There is no trace in the typical Derbyshire specimens of the coarse spiral suleation, represented in Prof. 
Phillips’s larger figure of the species; the transverse crenated striae, on the contrary, being strongly marked 
under the lens, and agreeing exactly with the surface of his Goniatites crenistria. 
As M. @Orbigny has found a more, and a less, compressed variety of most of the common Ammonites 
(indicating in his opinion the sexes of the species), I think there can be little doubt of the propriety of uniting 
the A. sphwricus with what Martin called the compressed variety thereof, and what Sowerby and other writers 
eall the G. striatus; more particularly as I find that the first lateral sinus is pointed in both when well marked 
(contrary to the supposition of Phillips), and that the difference of length noted in the first lateral lobe by 
M. de Koninck as distinctive of the species, varies to the slight extent alluded to in different parts of one 
specimen, 
