PLATE XXIX.* 
1, 2. Belemnites Ellipticus. ( Elliptical Belemnite.) Guard much elongated, elliptical; opaque; 
greyish-brown, terminating in mucronated point. 
3, 4. Actinoceras Verus. ( True Actinocineras). 
5, 7, 25. B. Elongatus. ( Elongated Belemnite.) V. Plate XXIX., fig. 11. 
6, 8. B. Abbreviatus. ( Shortened Belemnite.) V. Plate XXIX., figs. 18, 19. 
9, 11. B. SulcatUS. ( Burrowed Belemnite.) Guard sub-cylindrical, elongated, with longitudinal 
furrow and acute apex. 
10. Variety of B. SulcatUS, figs. 9, 11. 
12. Blood vessels on guard of B. Electrinus, figs. 23, 24. 
13, 14. B. Longissimus. ( Lengthened Belemnite.) Guard very strong, much lengthened, 
smooth, with conic point. 
15,16. B. Tripartitus. {Three-parted Belemnite.) Guard formed of three longitudinal portions, 
showing near apex three, distinct, longitudinal ridges. 
17, 18. Variety of B. Tripartitus, figs. 15, 16. 
19, 20. B. AduncatUS. {Booked Belemnite.) Guard cylindrical, very smooth; sometimes finely 
striated, with hooked apex, with four or five ridges; intervening sulci sometimes slightly tuberculated. 
21. Apex of B. Aduncatus, figs. 19, 20. 
22. Variety of B. Ellipticus, figs. 1, 2. 
23. 24. B. Electrinus. {Amber Belemnite.) Guard cylindrical, lower extremity conical; with 
mammillated point; amber coloured. 
26, 27. 0. Microscopica. {Microscopic Orthocera.) Taper, smooth ; septa remote ; aperture 
semi-oval. Length i in.; thickness less than ^ in. 
28. B. Gibsoni. {Gibson’s Belemnite.) Gradually tapering; smooth, shining; aperture nearly 
circular. Length f in.; diameter at aperture ^ in. 
29. 0. Ascicularis. {Ascicular Orthocera.) Very long, tapering abruptly; smooth; septa 
many, transversely parallel, regular, increasing with age ; aperture circular; siphunculus situate near 
one side. Length 1-^ in.; diameter at aperture not ^ in., at base in. 
30. 0. Obtusa. {Obtuse Orthocera.) Erect, taper, compressed ; smooth, with undulating, trans¬ 
verse strife; point for one quarter of an inch without strife. Diameter near base f in.; greatest 
known diameter 1-^ in. 
31. 0. Brownii. {Brown's Orthocera.) Subulate, arcuated; with seven longitudinal, elevated 
ribs; hence septangular form; surface smooth; septa many, undulating. Length 1J in.; dia¬ 
meter 4 in. 
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