Terebratula. 
MOLLUSCA. 
Lower Cbalk, Ilarnsey, Leeds, and Dorking, and the upper 
Greensand, Warminster and Blackdown. 
124. Terebkatula flicatilis. —The Fine-plaited Tore- 
bratula, pi. LVI. fig. 51, 52, and 02, 63. 
T. plimtilis. Sowerby, II. p. 37, pi. 118, fig. 1 ; and T. 
octoplicata , ib. fig. 2 ; Brongniart, Env. Paris, pi. 4, fig. 
5, 8. 
Gibbose, transversely obovato, length somewhat more than 
its depth, width about one-third greater than the length ; beak 
rather short, and slightly incurved ; larger valve less inflated 
than the other; centre elevated by twelve obtuse plaits, with 
fifteen or more on each side. Fig. 62 and 63, a variety dif- 
feringfrom the other in being somewhat longer, and in having 
from seven to nine plates only on the sinus. 
Upper Chalk, Gravesend and Norwich. 
125. Terebkatula pleurodonv —The Side-toothed Tere- 
bratula, pi. LVI. fig. 57 and pi. LVI.* fig. 2 to 7. 
T. pleurodon. Phillips, II. p. 222, pi. 12, fig. 16, 25, 26, 
27, 28, 20, and 30. Ib. Pall. Foss. p. 86, pi. 35, fig. 155. 
Transversely ovate ; beak prominent; hinge line arcuated ; 
surface with large prominent ribs, emanating from the um- 
bones, and terminating on the base; the intermediate furrows 
wide ; sides very deeply reflexo-dentate. 
The species is subject to much variety, and are thus defined by Pro¬ 
fessor Phillips, viz.— 
а. The mesial portion elevated, large; sides much reflexed, with very 
acute ribs, as in fig. 
б. j Raricosta —The ribs few. 
c. Poliodonta —Mesial ribs numerous; margin squared. 
Fig. 57, pi. LVI. is a gigantic specimen. 
Carboniferous Limestone, Bolland, Orton, and Ireland ; 
Devonian Limestone, Pilton and Petherwin. 
126. Terebkatula angularis. —The Angular Terebra- 
tula, pi. LVI. fig. 14, 15. 
T. angularis. Phillips, Pal. Foss. p. 80. pi. 35, fig. 162. 
Airypa pHncipilaris. Sowerby, Geo. Trans. 2d Ser. V. pi. 
57, fig. 5, 6, and pi. LV.* fig. 61, 62, the young shell. 
Pentagonal, convex ; beak prominent ; front elevated, with 
three or four plaits; margin compressed ; a deep angular fur¬ 
row emanates from the centre of the lower valve, aud is 
bounded by two angular ridges, terminating on the base. 
Devonian Limestone, Plymouth, Barton, and Eifel. 
127. Terebratula lateralis. —The Broad Tercbratula, 
pi. LVI.* fig. 30. 
T. lateralis. Sowerby, I. p. 180, pi. 83, fig. 1. 
Semiovate, gibbose, its breadth exceeding its length ; beak 
a little elevated and curved ; front greatly elevated in the 
centre, with three deep short plaits, producing three very deep 
angular notches, filled by sharp teeth in the opposite valve ; 
each side furnished with two plaits, which extend considerably 
below the centre; perforated or longer valvo flatter than the 
other; there is a great length iu the edge, between the central 
and lateral plaits. 
Carboniferous Limestone, Cork, Ireland, and Bolland, York¬ 
shire. 
128. Terebratula reniformis. — The Kidney shaped 
Terebratula, pi. LVI. fig. 40, 55, 56, and 38, 30. 
T. reniformis. Sowerby, V. p. 154, pi. 406, fig. I, 2, 3, 4. 
Reniform, bilobate, rounded, and inflated ; middle provided 
with three or four longitudinal rounded ridges, terminated by 
141 
acute plaits in the frontal margin; sides inflated ; the ridges 
and intermediate furrows are rounded; the corresponding 
notches in the margin acutely angular. 
This shell is liable to considerable variety iu the general contour and 
in the number of its ridges. 
Variety 1.—Destitute of a mesial ridge. 
Variety 2.— With from three to five obtuse mesial ridges. 
Variety 3.— From three to five acute mesial ridges., 
Carboniferous Limestone, Dublin and Cork. 
129. Terebratula platyloba.— The Flat-lobed Terebra¬ 
tula, pi. LVI. fig. 30 and 50. 
T. platyloba. Sowerby, V. p. 155, pi. 496, fig. 5, 6. 
Transversely ovate, considerably compressed, its width be¬ 
ing nearly double its length; umbo obtuse; base with seven 
or eight rather obtuse ridges, which extend upwards two-thirds 
the length of the valves ; several of the central ones somewhat 
acute; sides with one or two nearly obsolete plaits on their 
edges. 
Carboniferous Limestone, Clithero. 
130. Terebratula borealis. —The Northern Terebra¬ 
tula, pi. LVI. fig. 26. 
T. borealis. Schloth, Nac. pi. 20, fig. 6. T. plicatella. 
Dalmain, pi. 6, fig. 12. T. lacunosa. Sowerby, Sil. Syst. 
p. 611, pi. 5, fig. 19. 
Obovate, gibbose, obscurely trilobate, and provided with 
about sixteen acute longitudinal plaits, four or five of the 
middle ones in front considerably more elevated than the 
others; beak small, acute, and slightly incurved. Length 
seven lines, width eight lines. 
Devonian Shales, Ogwell and Plymouth ; Upper Ludlow 
Limestone, Ludlow aud Braubach, and the Wenlock Lime¬ 
stone, Wcnlock and Presteign. 
131. Terebratula chrysalis. —The Chrysalid Terebra¬ 
tula, pi. LVI. fig. 60, 61. 
7.\ chrysalis , T. Gervillii. Woodward, pi. 6, fig. 14, Schloth, 
M.G.S. Fr. pi. 16, fig. 9. Faugas, Mt. St., pi. 26, fig. 9. 
Oblong-ovate, sub-compressed ; beak extremely long, acute, 
and slightly incurved ; hinge line of lesser valve straight, with 
small auriform processes ; whole surface with pretty large 
hut not deep divergent ribs, producing a slightly crenulated 
margin. 
Woodward supposes it possible that this may be the youug of Trigo- 
noscimus lyra; but it is totally distinct from that species. 
The Upper Chalk, Norwich. 
132. Terebratula flexistria. — The Waved Striate 
Terebratula, pi. LVI. fig. 64, 65. 
T. flexistria. Phillips, IL p. 222, pi. 12, fig. 33, 34. 
Oblate, sub-depressed ; beak very small, hardly protruding 
beyond the hinge line; mesial elevation rounded ; lower valve 
somewhat smaller and flatter than the other, with an incon¬ 
spicuous beak ; sides considerably curved; surface with many 
flexous obtuse strim or small ribs. 
Carboniferous Limestone, Bolland and Newton. 
133. Terebratula mesogonia.— The Intcrangular Tere- 
bfatula, pi. LVI. fig. 72, 73. 
T. mesogona. Phillips, II. p. 222, pi. 12, fig. 10, 11, 12. 
Tetrahedral, frontal elevation single or cleft; sides pro¬ 
vided with ono or two ribs. 
Carboniferous Limestone, Bolland. 
