PLATE LIV.* 
I, 2. Atrypa Desquaniata. (Peeled Atrypa .) Oblong, gibbous; base obtuse ; smaller valve deeper than larger one ; 
with longitudinal striae; internally striated. 
3. A. Affinis. (Allied Atrypa.) Orbicular; with strong, radiating strife; upper valve gibbous, with elevated sinus 
in front; lower valve flat. 
4, 5. Composita Ambigna. ( [Ambiguous Composita.) Sub-pentangular ; beak produced, perforated; liinge-lino short; 
sides rounded ; with mesial furrow in larger valve ; base three-sided ; surface smooth. 
6,7. A. Pectinifera. ( Comb-like Atrypa.) Transversely obovate, convex, sub-compressed; beak small; with con¬ 
centric, ciliated fringes. 
8. A. Triangularis. (Triangular Atrypa.) Triangular; base, with two folds; beaks, hardly produced beyond 
circumference of valves. 
9, 10. Terebratula Praelonga. (Prolonged Terebratula.) Ovate, elongated, gibbose; base elevated, with depression 
in centre ; beak large, promineut; surface smooth. 
II, 12, 13, 13*. T. Sublobata. (Sublobate Terebratula.) Elongated; dorsal valve, grooved from beak to base; ventral 
valve grooved to margin, and trilobate; valves crossed by lines of growth. 
14. T. Lata. (Broad Terebratula.) Sub-orbicular, smooth, sub-depressed ; larger valve sub-carinated; beak prominent, 
straight; base rounded. 
15. T. Trilineata. ( Three-lined Terebratula.) Ovate-rhomboidal, sub-depressed; margin faintly undulated; valves, 
with two or three stria); beak convex, straight; base produced. 
16. Leptsena Hemisphaerica. (Hemispherical Leptcena.) Orbicular; larger valve inflated, with many, longitudinal 
striae and concentric ridges; hinge-line parallel; lesser valve flat, with longitudinal striae. 
17. 18. T. Virgo. (Virgin Terebratula .) 
19, 20, 21, 22. T. Variabilis. (Variable Terebratula.) Oblong, convex, smooth; beak produced, truncated; perforation 
large, round, truncated; internal area, with large sinus. 
23. T. Ornithocephala. (Bird's Head Terebratula.) Ovate, rliomboidal, gibbous; base straight, bounded by two 
lateral depressions on each valve; beak, with large perforation; sides depressed. 
24. T. Hastata. (Spear-shaped Terebratula.) V. Plate LI I., Figs. 9, 10. 
25,36. T. Biplicata. (Two-plaited Terebratula.) Oblong, gibbose; beak prominent, incurved ; sides rounded; base 
parallel, whence two, well-defined plaits. 
26, 27. T. Faba. (Bean-sliaped Terebratula.) Longitudinally elliptical, narrow, gibbose; beak short, prominent- 
front concave; surface smooth. 
28, 29. T. Obesa. (Swollen Terebratula.) Ovate, globose; valves convex; beak short, obtuse, incurved; base obtuse 
with shallow sinus in centre. 
30, 31, 32, 33. T. Carnea. (Flesh-coloured Terebrahda.) Sub-rotund, obtusely pentangular, depressed; valves convex 
smooth; beak small, flat; base flat, short; sides plain; some specimens of fine flesh-colour. Diameter, 1 in. 
34. T. Ovoides. (Oval Terebratula.) Oblong-ovate, smooth; beak produced; larger valve gibbous, sub-carinated- 
smaller valve convex; base produced. 
35. T. Intermedia. (Intermediate Terebratula .) Obscurely pentangular, depressed, smooth; larger valve, with two 
depressions; smaller valve with three; base, with deepish undulations. 
37,38. T. Tamarinda. (Tamarind Terebratula.) Orbicular, smooth ; margin obtuse; disc depressed ; beaks curved 
with flat ridge on each side. 
39, 40. T. Navicula. (Little Ship Terebratula.) Oblong, boat-shaped, smooth, beak short, incurved; upper valve 
flat; lower valve, with obtuse keel. Length and breadth, ^ in. 
41, 42. T. Resupinata. (Back-lying Terebratula.) Oblong-ovate; beak small, incurved; lowor valve obtusely 
carinated ; base, with large plait; sides elevated; lower valve, with obtuse, rounded keel and longitudinal ridge on each 
side. 
43, 44. T. Subundata. (Half-waved Terebratula.) Circular, depressed, smooth ; valves equally convex ; base straight, 
with single undulation on each side. 
45, 46. T. Semiglobosa. (Nearly Globular Terebratula.) Nearly globular, inflated, smooth; largo valve deeper, 
gibbous; smaller valve, with two elevations ; base undulated. 
47, 48, 49. T. Sacculus. (Little Bag Terebratula.) V. Plate LIL, Figs. 39, 40. 
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