PALAONTOGRAPHICAL SOCIETY. VOL, LXIY. GANOID FISHES OF BRITISH CARBONIFEROUS FORMATIONS. PALAONISCIDA. Pagr ok. Now: Paces 123—158; Prares XX XI—XXXV. THE FISHES OF THE ENGLISH CHALK. Parr VI. Paces 185—224; Piares XX XIX—XLVI. THE CRETACEOUS (ewe LTE RANCHI A. Vou. il, Parr Vil. Pages 261—284; Prares XLV—L. THE CARBONIFEROUS ARACHNIDA. Paces 1—84; Piates I—III. BRITISH GRAPTOLITES. Part VIII. Paces 359—414; Pirates XXX VI—XLI. IssugeD For 1910. California Academ Y of Seiences RECEIVED BY PURCHASE 2N\SOO Digitized by the Internet Archive in 2011 with funding from California Academy of Sciences Library http://www.archive.org/details/monographot641910pala THE PALAONTOGRAPHICAL SOCIETY was established in the year 1847, for the purpose of figuring and describing British Fossils. Hach person subscribing ONn Guinn is considered a Member of the Society, and is entitled to the Volume issued for the Year to which the Subscription relates. 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The followmg Monographs are in course of publication : The Fossil Sponges, by Dr. G. J. Hinde. The Graptolites, by Prof. Lapworth, Miss Elles, and Miss Wood. The Cambrian Trilobites, by Mr. Philip Lake. The Cretaceous Lamellibranchia, by Mr. H. Woods. The Paleoniscid Fishes of the Carboniferous Formation, and the Fishes of the Old Red Sandstone, by Dr. R. H. Traquair. The Fishes of the English Chalk, by Dr. A. Smith Woodward. ANNUAL REPORT PALAONTOGRAPHICAL SOCIETY, 1910, leek Che Council, Secretaries, and Members A LIST OF THE CONTENTS OF THE VOLUMES ALREADY PB ESE nD: Council and Officers elected March, 1910. President, HENRY WOODWARD, Ese, LL.D, F.R.S., F.GS. Vice-Presidents, Rev. Canon Bonney, D.Sc., F.R.S. G. J. Hinpr, Esq., Px.D., F.R:S. Str ARCHIBALD GeEIKIE, K.C.B., P.R:S. | E. T. Newton, Hsq., F.R.S. Council. H. A. Auuen, Hsq., F.G.S. | W. D. Lane, Esq., M.A., F.G.S. F. A. Baruer, Hsq., M.A., D.Sc., F.RB.S. Mrs. G. B. Lonaestarr. Rev. R. Asuineton Buuuen, B.A., F.G.S. | ‘a i iy & - Lie € 7 a 7 a = # : - a a a = a * > - : a _ '] ‘ . _ ad s sor s - i A \ ¢ - opal i! " : N —_— / j 3 s Ld U 4 7 i - 7 ~ _ADLARD AND SON, IMPR., LONDON AND DORKING. Fait ., J vi Nao al = = . ’ can ee EDAPHODON. 185 the inner aspect ; beak-tritor composed of a series of lamine, the other tritors consisting of numerous tubules ; median tritor divided (except when abraded) into two small and widely-separated parts, of which the anterior is placed on the edge of the symphysis, and the posterior behind the anterior outer tritor. Palatine plate with very large tritors, the two inner being broad, and the posterior of these tending to overlap the narrow outer tritor. Womerime plate with a concave or grooved symphysial surface ; the anterior tritor much larger than the others. Description of Specimens.—Vhough found most abundantly in the Cambridge Greensand, the dental plates of this species appear to occur at all horizons in the Chalk. Only one specimen, however, from the Chalk near Lewes, has hitherto been discovered to show all the dental plates of one mouth in a satisfactory state of preservation. This has already been described and figured by H. T. Newton, loc. cit., whose drawings of the left palatine and left mandibular dental plates are copied in Text-figs. 54, 55. In the mandibular plate the relative prominence of the beak varies considerably in different specimens, and the appearance of the inner or median tritor depends on the extent to which it is uncovered. In the left mandibular plate, shown in Pl. XL, figs. 4—4, for example, the beak is much longer than in the original of Text-fig. 55; while its median tritor (e.) is exposed only in two narrow patches and appears to be completely subdivided into two parts. The anterior outer tritor of the same specimen (fig. 4a, ¢.) is also relatively small and well separated from the outer oral margin. ‘To the same individual as the mandibular plate belongs the vomerine plate shown in PI. XL, fies. 5—5b. This, again, is remarkable for the prominence of the beak, and suggests that the vomerine dental plates named HMdaphodon gigas by HKgerton (Quart. Journ. Geol. Soc., vol. ii, 1847, p. 352, and Newton, op. cit., p. 17, pl. v, figs. 1, 2) really represent a variety of H. sedgwickt. Its beak-tritor is relatively large; the next four tritors are small; and then the sixth tritor of the series is of considerable size. Horizons and Localities.—Senonian zones: Norwich. 'Turonian zones: neigh- bourhood of Lewes, Sussex. Zone of Schloenbachiu varians: Dover, Kent. Also Gault, Red Chalk, Cambridge Greensand, and Lower Greensand. 2. Edaphodon mantelli (Buckland). Plate XLI, fig. 1. 1835-36. Chimera mantellii, W. Buckland, Proc. Geol. Soc., vol. ii, p. 206, and Phil. Mag. [3], vol. viii, p. 5. 1843. Ischyodus mantelli, P. M. G. Egerton, Proc. Geol. Soe., vol. iv, p. 156. 1843. Chimera (Psittacodon) mantellii, L. Agassiz, Poiss. Foss., vol. ii, p. 348, pl. xla, figs. 1, 2. 1847. Hdaphodon mantellii, P. M. G. Egerton, Quart. Journ, Geol. Soc., vol. iii, p. 352. 1850. Hdaphodon mantelli, F. Dixon, Geol. Sussex, p. 203, pl. xxxiv, figs. 6, 7. 1878. Edaphodon mantellii, E. T. Newton, Chimeroid Fishes Brit. Cret. Rocks (Mem. Geol. Surv.), p. 14, pl. iv, figs. 1—9. 1891. Edaphodon mantelli, A. S. Woodward, Catal. Foss. Fishes B. M., pt. 11, p. 75. 24 186 FOSSIL FISHES OF THE ENGLISH CHALK. Type.—Pair of imperfect mandibular dental plates ; British Museum. Specific Characters.—Dental plates much resembling those of H. sedgwicki, but more slender and not attaining so large a size. Description of Specimens.—The mandibular dental plates of the type specimen display both the outer and the inner aspects, and have already been described and ficured by Agassiz and Newton, loc. cit. An exactly similar plate, only crushed in the lower half of the symphysial region, is shown in Pl. XLI, figs. 1, la. Its prominent beak and very wide symphysial facette are well shown, and the arrange- ment of the tritors is also seen. The median tritor (e.) is completely exposed, and observed to be continuous to the symphysis. The palatine dental plate is associated with a mandibular pair from Lewes, described by H. 'T. Newton, loc. cit. It differs from that of HM. sedgwicki in being more slender, with the tritors longer and narrower. A right mandibular dental plate from Glynde in the Willett Collection, Brighton Museum (No. 143), exhibits the median tritor subdivided into several portions, but seems to represent only a variety of MH. mantelli (H. T. Newton, loc. Cte, pe, pl aveatig= lO}, Horiwons and Localities—Turonian zones: neighbourhood of Lewes and Houghton, Sussex. Zone of Holaster subglobosus: Glynde and Clayton, Sussex ; Burham, Kent. Zone of Schloenbachia varians; Dover, Kent. Undetermined zones: Brighton, Sussex ; Guildford, Surrey. 3. Edaphodon agassizi (Buckland). Plate XLI, fig. 2. 1835-36. Chimera agassiziit, W. Buckland, Proc. Geol. Soc., vol. ii, p. 206, and Phil. Mag. [3], vol. viii, p. 5. 1843. Ischyodus agassizi, P. M. G. Egerton, Proc. Geol. Soc., vol. iv, p. 156. 1843. Chimera (Ischyodon) agassizii, L. Agassiz, Poiss. Foss., vol. i, p. 341, pl. xla, figs. 3, 4 (? 5), pl. xlc, fig. 16 (non figs. 14, 15). 1844. Chimera, G. A. Mantell, Medals of Creation, p. 621. 1878. Edaphodon agassizii, H. T. Newton, Chimeroid Fishes Brit. Cret. Rocks (Mem. Geol. Surv.), Dele) pl. 1891. Edaphodon agassizi, A. 8. Woodward, Catal. Foss. Fishes B. M., pt. ui, p. 77. T'ype-—Imperfect mandibular tooth; British Museum. Specific Characters.—Mandibular dental plate comparatively short and stout, and the beak only slightly produced ; symphysial facette scarcely occupying one- third of the inner aspect; beak-tritor composed of a series of lamin, the other tritors consisting of numerous tubules; median tritor very broad, occupying the greater portion of the oral surface, and apparently exposed above throughout its length. Description of Specimens.—The type specimen is so much broken along its EDAPHODON. 187 anterior and post-oral margins that its shape is not completely shown. A nearly perfect left mandibular dental plate, however, is represented in Pl. XLI, figs. 2, 2a, 2b, and exhibits all the characters of the species. Its outer face (fig. 2) is marked only by the usual structural lines, without any supplementary layer near the oral border. The symphysial facette is well marked off from the rest of the inner face (fig. 2), and in this well-preserved specimen the median tritor (e.) is exposed only in its upper portion, where it is continuous. The two outer tritors (fig. 2b, ¢., d.) are small and placed shghtly within the oral margin. The upper dental plates remain unknown or unidentified. Horizon and Localities—Zone of Holaster subglobosus ; Hamsey and Southeram, Sussex; Burham, Kent; Dorking, Surrey. 4, Edaphodon reedi, Newton. Plate XL, fig. 6. 1878. Edaphodon reedi, KE. T. Newton, Chimeroid Fishes Brit. Cret. Rocks (Mem. Geol. Surv.), pl oeplavai. T'ype.—Mandibular dental plate ; York Museum. Specific Characters.—Dental plates with tritors excessively reduced. Man- dibular plate with a very prominent beak, and the symphysial facette occupying at least one-third of the inner aspect; beak-tritor composed of a series of lamine, the other tritors consisting of numerous tubules; median tritor reduced to a small space on the edge of the symphysis ; posterior outer tritor often absent. Palatine dental plate with the posterior inner tritor very small or absent, and the outer smaller than the anterior inner tritor. Description of Specimen.—This is a large species represented by several dental plates from the Cambridge Greensand, but apparently known only by one specimen from the Lower Chalk. Even this fossil (Pl. XL, fig. 6) is not very characteristic, and exhibits an extreme reduction of the tritors. The dental plate is evidently incomplete behind, but is otherwise damaged only by a transverse fracture. There is only one diminutive, elongated inner tritor (a.), while the outer tritor (¢.) is reduced to insignificance. Horizons and Localities. — Zone of Holaster subglobosus: Glynde, Sussex. Cambridge Greensand. Fin-spine or Hdaphodon. A large part of a dorsal fin-spine is associated with one specimen of the mandibular dentition of I. agassizi described by Newton (loc. cit., p. 18, pl. 1, fig. 3). The fin-spine of Hdaphodon is thus shown to resemble that of the existing Chimera and also that of the typically Mesozoic genus Ischyodus. It is long, 188 FOSSIL FISHES OF THE ENGLISH CHALK. slender, laterally compressed, and only shghtly curved, with the flattened sides ornamented by irregular longitudinal strize (Pl. XLI, figs. 3, 4). The anterior border is compressed to a sharp edge, which is surmounted by a slight, beaded ridge of enamel, while the grooved posterior face (fig. 4) bears a close series of downwardly-curved, enamelled denticles (fig. 4a) along each edge for the greater part of its length. The spine is hollow and is cleft behind at its base, where it originally united with the supporting cartilage. Genus ISCHYODUS, Heerton. Tschyodus, P. M. G. Egerton, Proc. Geol. Soc., vol. iv, 1843, p. 155. Generic Characters.—Mandibular dental plate usually massive, with a well- defined hard layer on the outer aspect immediately below the oral margin; its symphysial facette narrow ; one anterior tritor usually present, sometimes several ; one median tritor, and two or more outer tritors. Palatine plate also massive, with outer thickening; four tritors present, two being inner, one median, and one outer. Vomerine plate more or less quadrate in side view, with tritors on the oral margin; post-oral region not laterally expanded, and usually with a definite hard thickening. Dorsal fin-spine laterally compressed, more or less longitudinally ridged, sometimes even rugose, with a double series of posterior denticles. Head- spine of male short, arched, with a terminal cluster of denticles. Type Species.—Ischyodus townsendi (Agassiz, Poiss. Foss., vol. 11, 1843, p. 343, pl. xl, figs. 20—22, pl. xle, figs. 17, 18), from the Portlandian of 8. England. Remarks.—This genus is typically of Jurassic age, and is known by nearly complete skeletons from the Lithographic Stone of 8. Germany. Only rare fragments occur in the Chalk. 1. Ischyodus thurmanni, Pictet and Campiche. Plate XL, fig. 7; Text-figure 56. 1843. Ischyodus brevirostris, P. M. G. Egerton, Proc. Geol. Soc., vol. iv, p. 156 (name only). 1843. Chimera (Ischyodon) brevirostris, L. Agassiz, Poiss. Foss., vol. iii, p. 344 (name only). 1843. Chimera (Ischyodon) agassizii, L. Agassiz (errore), tom. cit., pl. xle, figs. 14, 15. 1858. Ischyodus thurmanni, Pictet and Campiche, Foss. Terr. Cret. Ste Croix (Pal. Suisse), p. 76, pl. ix, fig. 8. 1862. Ischyodus agassizi, W. H. Bensted (errore), Geologist, vol. v, p. 378. 1867. Ischyodus bouchardi, H. H. Sauvage, Catal. Poiss. Second. Boulonnais (Mém. Soc. Acad. Boulogne-sur-Mer, vol. ii), p. 81, pl. iv, fig. 6. 1876. Ischyodus brevirostris, E. T. Newton, Quart. Journ. Geol. Soc., vol. xxxii, p. 326, pl. xxi, fig. 5. 1878. Ischyodus brevirostris, E. T. Newton, Chimeroid Fishes Brit. Cret. Rocks (Mem. Geol. Surv.), p- 27, pl. ix. 1891. Ischyodus thurmanni, A. 8. Woodward, Catal. Foss. Fishes B. M., pt. i, p. 67. ISCHYODUS. 189 T'ype.—Imperfect palatine dental plate from the Gault of Switzerland. Specific Characters.—Mandibular dental plate attaining a length of about 10 cm., very stout, with a deeply sinuous oral margin, acute eminences correspond- ing with the outer tritors, and the beak prominent; post-oral margin much less vertically inclined than the symphysial margin; beak-tritor minute; outer tritors well developed ; median tritor narrow or of moderate width, occupying the greater part of the oral surface immediately behind the anterior outer tritor. Palatine dental plate with the posterior inner tritor of moderate or large size, and the median tritor not extending so far forwards as this; outer tritor much elongated. Description of Specimens.—The dental plates of this species are most abundant in the Gault, whence the type specimen was obtained. Only twoexamples appear to be known from the English Lower Chalk. The right mandibular plate, shown of the natural size in Text-fie. 56, A, 1S more delicate than the typical speci- mens from the Gault and Cambridge Greensand (Text-fig. 56, B, c), with a narrower symphysial facette. It is also peculiar in having the post-oral margin nearly parallel with the anterior margin, and its median tritor is rather remote, being almost entirely behind the anterior outer tritor. em. A few rather large, oval, dermal tubercles with recurved spines, probably on the paired fins. Upper anterior teeth relatively small, and the opposing teeth of the lower jaw very narrow and slender. Description of Specimens.—The type specimen in the Willett Collection exhibits the remains of the head described and figured, loc. cit. So far as they can be compared, the cartilages resemble those of the existing Squatina. Among the numerous scattered teeth, those from the front of the mouth are distinguishable. Those near the symphysis of the mandible (Pl. XLVII, fig. 7) are relatively high and slender, while the opposing teeth (fig. 8) attain but small dimensions. More posteriorly, both above and below, the teeth begin to exhibit the usual lateral elongation (figs. 9, 10) characteristic of the sides of the mouth. The minute granules of shagreen (fig. 11) are mostly oval in shape, having the outer enamelled surface ornamented with longitudinal or radiating ridges. The larger tubercles, like those occurring on the margins of the paired fins of the existing Squatina, are also of an oval form, with a slightly crenulated margin (fig. 12). From the middle of each there rises a large, backwardly directed spine, which is laterally compressed and well enamelled. It is difficult to recognise any distinctive features in the teeth of the different species of Squatina. In S. cranet, however, the anterior lower teeth seem to be more slender than in other known forms, and the anterior upper teeth are remark- ably small. In this species also the spinous dermal tubercles are relatively much larger than in the existing Squatina angelus, and such tubercles have not hitherto been observed in any of the extinct species. Horizon and Locality.—Zone of Holaster subglobosus : Clayton, Sussex. Teeth of Squatina have also been recorded from the Chalk of Lewes and Brighton (A. 8. Woodward, Proc. Geol. Assoc., vol. xii, 1894, p. 191, pl. v, figs. 2,5), and from the zone of Belemnitella mucronata, near Norwich. PATH 2OCKIXxX. Fia. PAGE. 1. Coprolite usually ascribed to Macropoma, nat. size.——Chalk; Kent. Harford Collection (B. M. no. P. 5629). 180. 2. Part of a similar coprolite, nat. size-—Chalk; near Lewes. Mantell Collection (B. M. no. 4515). 180. 3. Macropoma precursor, sp. noy.; portion of trunk, nat. size, with (3 a) three scales enlarged to five-halves nat. size-—Base of zone of Holaster subglobosus ; Burham, Kent. G. KE. Dibley Collection (B. M. no. P. 10810). do’., anterior dorsal fin ; /., scales of lateral line. } 182. 4. Hlasmodectes willetti, Newton ; right side view of head and portion of trunk, nat. size, with (4a) some ring-vertebree and (4/) the distal end of the dorsal fin-spime, both enlarged three times.—-Zone of Holaster subglobosus ; near Lewes. Sedgwick Museum, Cambridge. d., dorsal fin-spine ; md., mandibular dental plate; pcet., pectoral arch; pl., palatine dental plate; v., vomerime dental plate. ete 5. Ditto; dorsal fin-spine, three-halves nat. size-—Chalk; Kent. Harford Collection (B. M. no. P. 5624). 192. 6. lasmodectes sp.; dorsal fin-spme above portion of pectoral arch, nat. size., with (6a) portion of base of spine enlarged three times.— Zone of Holaster subglobosus ; Clayton, Sussex. Willett Collection no. 98, Brighton Museum. 192: PALAZONTOGRAPHICAL SOCIETY, I910. PI. XXXIX. A.S.Woodward. English Chalk Fishes. West, Newman imp. H.Searvle delet lith. A 4-6. Elasmodectes. . Macropoma. este Fie. i) ce 6. a | PEAT Be XI: Hlasmodectes willetti, Newton; pair of mandibular dental plates, inner or oral view, nat. size, with that of right side enlarged three times from within (1a) and from above (10). The type specimen.—Zone of Holaster subglobosus ; Southeram, near Lewes. Willett Collection no. 148, Brighton Museum. Ditto ; mandibular dental plate seen from above, twice nat. size.-—Zone of Holaster subglobosus; Burham, Kent. Mrs. Smith’s Collection (B. M. no. 49024). Ditto ; left mandibular dental plate, mer view and (3 a) symphysial surface, nat. size.—Zone of Holaster subglobosus; Burham. G. EH. Dibley Collection (B. M. no. P. 10047). Hdaphodon sedgwicki (Agassiz); left mandibular dental plate, outer, inner (4) and upper (40) views, two-thirds nat. size-—Senonian zone ; Norwich. Bayfield Collection (B. M. no. P. 414). a., beak with tritor; c., ¢., anterior and posterior outer tritors ; ¢., median tritor. Ditto; vomerine dental plate of same specimen, outer, inner (5), and lower or oral (5) views, two-thirds nat. size. Hdaphodon reedi, Newton; right palatine dental plate, oral view, nat. size.—Zone of Holuaster subglobosus ; Glynde, Sussex. Capron Collection (B. M. no. 49727). a., inner tritor ; ¢., outer tritor. Ischyodus thurmannt, Pictet and Campiche; right palatine dental plate, oral view, showing tritors, nat. size.—Zone of Holaster subglobosus ; Burham, Kent. Mrs. Smith’s Collection (B. M. no. 49019). PAGE. Lot HOW: 191. 189: PALAEONTOGRAPHIGAL SOCIETY, I9I0O, A.S.Woodward. English Chalk Fishes. 2%: A.H.Searle del.et lith. 1-3. Elasmodectes. 4-6. Edaphodon. 7. Ischyodus. EL oa: West, Newman imp. Fia. bo 6. PLATE XLII. PAGE. Edaphodon mantelli (Buckland) ; left mandibular dental plate, inner and (1a) upper views, two-thirds nat. size.—Turonian zone; Lewes, Sussex. B.M. no. P. 5405. a., beak with tritor; c., d., anterior and posterior outer tritors; e., median tritor. 186. Hdaphodon agassizi (Buckland); left mandibular dental plate, outer, inner (2a), and upper (2b) views, nat. size—Zone of Holaster subglobosus ; Southeram, near Lewes. Capron Collection (B. M. no. 49723). Letters as in fig. 1. 187. Hdaphodon sp.; distal portion of dorsal fin-spine, side view, nat. size.— Zone of Holaster subglobosus ; Blue Bell Hill, Burham. 8S. J. Haw- kins Collection (B. M. no. P. 6525). 188. Hdaphodon sp.; hinder view of portion of dorsal fin-spine showing double series of denticles, nat. size, with (4) some of the denticles in side view enlarged three times.—Zone of Holaster subglobosus ; Burham, Kent. B. M. no. 43390. 188. Ischyodus (2) incisus, Newton ; left mandibular dental plate, outer, inner (5a), and upper (5b) views, nat. size, with (5c) broken section of beak enlarged twice to show tritors. The type specimen.—Chalk ; Kent. Toulmin Smith Collection (B. M. no, 41683). 190. Ditto; left mandibular dental plate, outer view, nat. size—Zone of Holaster subglobosus ; Burham. B. M. no. 47942. 190. Ditto; left vomerine dental plate found with the preceding specimen, outer and (7 a) inner views, nat. size. B. M. no. 47943. 190: Celorhynchus cretaceus, Dixon; imperfect spine, nat. size, with (8 a) portion of ornament enlarged three times. The type specimen.— Zone of TLHolaster subglobosus; Sussex. Hnniskillen Collection (B. M. no. P. 3942). 193. Ditto; transverse section of spine, four times nat. size, with (9 a) part of the same more highly magnified.—Senonian zone; Norwich. Bayfield Collection (B. M. no. 48956 a). 193. * — PALZONTOGRAPHICAL SOCIETY, I9I0O. el alee A.S.Woodward, English Chalk Fishes. mp. L West, Newman A.H.Searle del.et lith 8, 9. Coelorhynchus. 5-7. Ischyodus. 1-4. Edaphodon. PLATE, XEIT, Fra. PAGE. 1,2. Scyllinm antiquum (Agassiz); two teeth, outer view, five times nat. size. From the type specimen.—Zone of Holaster subglobosus ; Burham, Kent. Enniskillen Collection (B. M. no. P. 5889). 194. 3. Ditto; another tooth of same specimen, outer, inner (5 @), and side (5 b) views, five times nat. size. 194. 4. Ditto; two shagreen granules of same specimen, one shown in inner and (4a) side views, the other (4) in outer view only, twelve times nat. size. 194. 5,6. Seyllium dubium, A. 8. Woodward; two teeth, outer and inner views respectively, eight times nat. size. From the type specimen.— Zone of Fine subglobosus ; Dover, Kent. Gardner Collection (B. M. no. 47288). 195. 7. Canttoscyllium decipiens, A. S. Woodward; anterior portion of skeleton, lower view, nat. size. The type specimen.—Zone of Holaster subglobosus ; Burham. Enniskillen Collection (B. M. no. P. 5890). hy., hyoid arch (fragment) ; l., labial ; md., mandible; pet., pectoral arch ; ptq., pterygo- quadrate ; v., prominence on latter. 196. 8, 9. Ditto; two teeth of same specimen, outer view, four times nat. size 196. 10. Ditto: base of tooth of same specimen, seen from attached face, font times nat. size. 196. 11. Ditto; left ascending portion of pectoral arch of same specimen ; outer view, nat. size. 196. 12-15. Coraw pristodontus, Agassiz; four isolated teeth, outer views, nat. size.—Zone of Beleminitella mucronata; Norwich. Bayfield Collection (B. M. no. 48946). 198: 16-18. Coraw falcatus, Agassiz; three isolated teeth, outer view, the first and third nat. size, the second enlarged one and a half times. Type specimens.—Turonian zone; Lewes. Mantell Collection (B. M. nos. 4454, 4457, 4465). 198: 19. Ditto; tooth, outer view, nat. size-—English Chalk (B. M. no. 40544). 199. 20. Ditto; tooth, inner view, nat. size-—Chalk; Kent. Enniskillen Collection (B. M. no. P. 2333). NAT). 21. Ditto; imperfect large tooth, inner view, nat. size. The type specimen of Corav mavimus, Dixon.—Turonian zone; Houghton, Sussex. Dixon Collection (B. M. no. 25758). £99; 22. Ditto; tooth, outer view, nat. size. —Chalk, Kent. Egerton Collec- tion (B. M. no. P. 1204). 199: 23, 24. Ditto; two isolated teeth; outer and inner views respectively, one and a half times nat. size.—Zone of Houlaster subglobosus ; Blue Bell Hill, Burham. 8S. J. Hawkins Collection (B. M. no. P7652 13). 199, 25. Ditto; hinder tooth, inner view, one and a half times nat. size.—Zone of Holaster subglobosus; Dover. Gardner Collection (B. M. no. P. 48), 199. 26. Ditto; tooth, mner view, nat. size.—lIbid. Gardner Collecticn (B. M. no. 47145). 199. 27. Ditto; small upright tooth, outer view, one and a half times nat. size.—Chalk ; Kastbourne, Sussex. Capron Collection (B. M. no. 49942), 199: 28. Ditto; similar tooth, imner view, one and a half times nat. size.— Turonian zone; Lewes. Mantell Collection (B. M. no. 4455 a), INS} PALAZONTOGRAPHICAL SOCIETY, 1910. A.S.Woodward, English Chalk Fishes. Ile GLa. A.H.Searle del.et lith West, Newman imp. 16. Scyllium-, /—i. Cantioseyliwum:” 42 1485 Gore xe Fria. 5-9. 10. Li. We ame 14. PLATE XUAN. Corarv jaekeli, A. S. Woodward; tooth, outer view, twice nat. size.— Zone of Marsupites (Uintacrinus-band) ; near Salisbury. Dr. H. P. Blackmore’s Collection. Ditto; tooth, outer view, twice nat. size.—Ibid. Dr. H. P. Blackmore’s Collection. Ditto; tooth, outer view, twice nat. size-—Zone of Actinocamax quadratus ; Hast Harnham, Salisbury. Dr. H. P. Blackmore’s Collection. Corax affinis, Agassiz; small anterior tooth, outer view, twice nat. size.—Zone of Belemnitella mucronata; Norwich (B. M. no. P. 5812). Ditto; five isolated teeth, 7 and 9 inner view, others outer view, one and a half times nat. size.—Ibid. B. M. nos. 48947, 36916, 48956 e, 35650, P. 5812 a Ovyrhina mantelli, Agassiz; small tooth of uncertain position, outer view, one and a half times nat. size.—Chalk ; Guildford. Capron Collection (B. M. no. 49954). Ditto; anterior tooth with lateral denticle, outer view, nat. size.— Chalk; Sussex. Hgerton Collection (B. M. no. P. 1263). Ditto; postero-lateral tooth with lateral denticle, outer view, nat. size.—Zone of Schloenbachia varians; Dover. Gardner Collection (B. M. no. 47255). Ditto ; another lateral tooth with traces of denticles, outer view, nat. size.—Chalk; Sussex. B. M. no. P. 5408. Ditto; vertebral centrum, upper view and (14a) vertical transverse section, nat. size, Showing radiating structural plates and hollows for the cartilaginous bases of the arches.—Chalk ; Sussex. Dixon Collection (B. M. no. 25939). Ditto; another vertebral centrum in vertical transverse section, nat. size.—Zone of Holaster subglobosus ; Glynde, near Lewes. Capron Collection (B. M. no. 49898). Oxvyrhina angustidens, Reuss; anterior tooth, inner view, one and a half times nat. size.—Zone of Holaster subglobosus ; Blue Bell Hill, Burham. 8. J. Hawkins Collection (B. M. no. P. 9034). 17. Ditto; anterior tooth, outer view, nat. size.—Zone of [Holaster sub- 18. Lg: 20. globosus ; Halling, Kent. Toulmin Smith Collection (B. M. no. 41707 Db). Ditto; lateral tooth, outer view, one and a half times nat. size.—Zone of Terebratulina gracilis; Whyteleafe, Surrey. G. EH. Dibley Collection (B. M. no. P. 10050). Ditto; two associated teeth, one and a half times nat. size.-—Zone of Holaster subglobosus; Glynde, near Lewes. Capron Collection (B. M. no. 49948). Ditto; tooth, outer view, nat. size.—Zone of Holaster subglobosus ; Blue Bell Hill, Burham. §8. J. Hawkins Collection (B. M. no. P. 6522). PAGE. 204. 204. PALAZ-ONTOGRAPHICAL SOCIETY,1I91I0O. A.S.Woodward, English Chalk Fishes. Pl A.H.Searle del.et lith West, Newman imp. io. Corax.) 10 20s. One neler PDATE XT. Fia. PAGE. 1. Ovyrhina crassidens, Dixon; tooth, outer and (1a) lateral views, nat. size. The type specimen.—Turonian zone; Houghton, Sussex. Dixon Collection (B. M. no. 25823). 205. 2. Ditto; anterior tooth, outer and (2 a) inner views, nat. size.—Chalk ; Sussex. Dixon Collection (B. M. no. 25786). 205. 3. Lamna appendiculata, Agassiz; tooth, outer view, nat. size.—Chalk ; Arundel, Sussex. Capron Collection (B. M. no. 49949). 208. 4. Ditto; tooth, outer view, nat. size-——Zone of Belemnitella mucronata ; Norwich. Bayfield Collection (B. M. no, 48956 a). 208. 5. Ditto; tooth with accessory denticles, outer view, nat. size-—Chalk ; Greenhithe, Kent. Slatter Collection (Be Mino. Pe s597): 208. 6. Ditto; stout tooth, inner view, nat. size.—Zone of Holaster subglobosus ; Dover. B. M. no. 35544. 208. 7. Ditto; wrinkled tooth, outer view, nat. size.—-Chalk; Kent. Egerton Collection (B. M. no. P. 1280 b). 208. ,9. Lamna arcuata, A. 8. Woodward; two isolated teeth, one in outer and (8 «) lateral view, the other in outer and (9 @) inner view, nat. size. Fio. 8 is type specimen.—Zone of Pelemnitella mucronata ; Norwich. Bayfield Collection (B. M. no. 48956 5). 208. 10. Lamna semiplicata (Agassiz); tooth, outer, inner (10 @), and lateral (10 b) views, nat. size.—Chalk; near Rochester, Kent. B. M. no. 43514. 209. 11. Ditto; more posterior tooth, outer view, nat. size.—Chalk; Charing, Kent. Harris Collection (B. M. no. P. 327). 209. 12. Lamna suleata (Geinitz) ; anterior tooth, outer and (12 a) lateral views, nat. size.—Chalk; Surrey. Bowerbank Collection (B. M. no. 39054). 209. 13. Ditto; more posterior tooth, outer view, nat. size.-—Chalk; Lewes. B. M. no. P. 5402. 209. 14. Scapanorhynchus rhaphiodon (Agassiz); anterior tooth, outer view, nat. size.—Hnelish Chalk. B.M. no. P. 404. 212. 15. Ditto; anterior tooth, imner view, nat. size, with (15 a) portion of ornament of inner face enlarged four times.—Chalk; Kent. B. M. no. 43080. 212. 16. Ditto; contorted anterior tooth, side view, nat. size.—Zone of Belemni- tella mucronata; Norwich. B. M. no. P. 5892. Qe 17. Ditto; more posterior tooth, inner view, one and a half times nat. size. —Chalk; Shalford, near Guildford. Capron Collection (B. M. no. 49952). 212) 18. Scapanorhynchus subulatus (Agassiz); anterior tooth, outer view, nat. size.—Zone of Holaster subglobosus ; Halling, Kent. Toulmin Smith Collection (B. M. no. 41707). 213, 19. Ditto; anterior tooth, inner view, one and a half times nat. size.— English Chalk. B.M. no. P. 5758. 213. 20. Ditto; lateral tooth, outer view, one and a half times nat. size.—Same history as fig. 18. 213. 21. Ditto; postero-lateral tooth, outer view, one anda half times nat. size.— Chalk; Sussex. Dixon Collection (B. M. no. 25934). 213. PALAZEONTOGRAPHICAL SOCIETY, I9I0O. A.S.Woodward,linglish Chalk Fishes. Tell, DOLE f\ vy N ie Roa A.H.Searle del.etlith. West, Newman imp. 1-2. Oxyrhina. 3-13. Lamna. 14-21. Scapanorhynchus. unl lee Fic. il. ro Or Pia Sy. PAGE. Cestracion canaliculatus, Egerton ; lower view of imperfect jaws, nat. size, with (1) anterior tooth, outer view, three times nat. size, and (1 /) upper principal lateral teeth, coronal view, one enlarged three times and (1¢) part of its ornament enlarged five times; also (1d) three dermal tubercles, one being in outer view, one from the side, and one from below, enlarged twelve times.—Turonian zone; Malling, near Lewes. Willett Collection no. 182, Brighton Museum. id., mandible ; pty., pterygo-quadrate (upper jaw); s., shagreen: I, I, 1, three series of principal lateral teeth of upper jaw. 210. Ditto; anterior tooth, inner view (2a), hinder principal lateral teeth and another lateral tooth (v}, coronal view (2b), the same principal lateral teeth, seen from attached face, showing oblique perforation (2c, c.), and one anterior principal lateral tooth, coronal view (2 ), all three times nat. size.—Chalk; Guildford. Capron Collection (B. M. no. 49735). 215. Ditto; portion of vertebral column, with anterior dorsal fin-spme.— Chalk; Sussex. B. M. no. P. 4921. Diltas Ditto (?); lateral tooth, coronal view, nat. size, with (4a) part of its ornament enlarged five times.—Turonian zone; Lewes. Mantell Collection (B. M. no. 4166). 2.16. Ditto (?); lateral tooth, coronal view, nat. size.—Zone of Terebratulina gracilis; Warlngham, Surrey. G. H. Dibley Collection (B. M. no. P. 6489). 216. Synechodus dubrisiensis (Mackie); right side view of jaws, nat. size, with (6) an antero-lateral tooth, outer view, enlarged three times. The type specimen.—Zone of Holaster subglobosus ; Dover. md., mandible; p., pterygo-trabecular process; plq., pterygo-quadrate. B. M. no. 36908. PAW Ditto; jaws and hyoid arch, seen from the left side and (7a) from below, nat. size, with three teeth (7b, 7c, 7d), enlarged three times. —Chalk; Kent. Toulmin Smith Collection (B. M. no. 41675). chy., ceratohyal ; l., hyomandibular ; of., otic process, with facette for articulation with postorbital process of skull; w., tuberosity on ceratohyal; other letters as in fig. 6. 2 + = epg he” mm eam. PALZONTOGRAPHICAL SOCIETY,1I910. A.S.Woodward,English Chalk Fishes. il ie GE A.H.Searle del.et lith. West,Newman imp. io, Cestracion. 6 —7, Symecmocuce Fie. bo © . 6. PLAT xoloWale PAGE. Synechodus dubristensis (Mackie) ; dentition of one jaw, twice nat. size, with six teeth, of the series indicated by numbers, enlarged four times.—Chalk ; Sussex. Willett Collection, Brighton Museum. 218. Ditto ; remains of anterior part of skeleton, seen from below, nat. size. —TZone of Holaster subglobosus; Burham, Kent. Mrs. Smith’s Collection (B. M. no. 49032). pet., pectoral arch ; 1, first vertebral centrum. Also 2a, shagreen, eight times nat. size, occurring on jaws from same zone at Dover ; Gardner Collection (B. M. no. 47287). 219. Synechodus nitidus, sp. nov.; teeth, three times nat. size, from different parts of jaw (8a—3c), with (8¢) shagreen enlarged eight times. The type specimen.—Zone of Holaster subglobosus ; Snodland, Kent. Egerton Collection (B. M. no. P. 1295). 219. Ditto; antero-lateral tooth, outer view, twice nat. size.—Zone of Holaster subglobosus; Wouldham, Kent. G. HE. Dibley Collection (B. M. no. P. 10228). Zig: Synechodus ilingwortht (Dixon); tooth, inner and (5a) coronal views, one and a half times nat. size.—Chalk; Sussex. Egerton Collection (B. M. no. P. 2148). 220. Ditto; tooth, outer and (6 a) coronal view, one and a half times nat. size. —Yone of Holaster subglobosus ; Southeram, near Lewes. B. M. no. P.29879. 220. Ditto; five associated teeth, nat. size—Hnelish Chalk. B.M.no. 45311. 220. Synechodus vecurvus (Trautschold) ; tooth, outer and (8) lateral views, nat. size-—Zone of Belemnitella mucronata; Norwich. Bayfield Collection (B. M. no. 48953). 221. PALZONTOGRAPHICAL SOCIETY, I9IO. A.S.Woodward,English Chalk Fishes. Jello EVIE: RT SO meee Li h Siwy, a / ‘| NOAA ai tla tates AES. A.H.Searle del.et lith West,Newman imp. Synechodus. Palxontographical Society, 1910. ee MOON OG, ix A (PB EL OF THE CRETACHOUS LAMELLIBRANCHIA ENGLAND. HENRY WOODS, M.A. UNIVERSITY LECTURER IN PALMHOZOOLOGY, CAMBRIDGE VO: Mir = PAR Von: INOCERAMUS. PaGEs 26]1—284; Puates XLV—L. EON DION: BRINTED FOR THE PADAONTOG RA PHVCAh SO10 Taine JANUARY, 1911. CUSPIDARIA. 261 Affinities —When describing the Mollusca of the Chalk Rock in 1897 only an imperfect specimen of C. pulchra was available for study, and I identified it with (. caudata (Nilsson). Two better specimens from Norwich have now been seen, and anew figure of Nilsson’s type has been published by Hennig.’ The English form—figured by Sowerby as Leda pulchra—differs from the type of C. caudata in the relatively greater height of the anterior part of the shell, the more nearly posterior position of the umbones, and in the posterior rostrum proceeding from the level of the hinge-line instead of below it. C. pulchra approaches closely the specimen figured by Goldfuss* as C. caudata, and it was chiefly on account of this resem- blance that I identified the English form with Nilsson’s species. Stoliezka® and. Hennig, however, consider that Goldfuss’ specimen is not an example of C. caudata. If all the specimens figured by foreign writers as C. caudata really belong to that species then it is obviously extremely variable and might well include C. pulchra. Without an opportunity of studying a series of foreign specimens and a larger number of English examples it seems, at present, preferable to regard C. pulchra as distinct from C.caudata. None of the English specimens shows evidence of the existence of such a long posterior beak as is present in the type of C. caudata. A specimen of Cuspidaria from the Upper Greensand of Devizes (Plate XLIV, fig. 7) resembles some specimens of CU. pulchra and may be provisionally referred to that species. T'ype-—The type, from the “ Chalk of Kent,”’ cannot now be found. Distribution—Chalk Rock of Cuckhamsley, Berkshire, and Henley Park. Upper Chalk (zone of Belemnitella mucronata) of St. Giles’ Gate and Horstead, near Norwich. 1 «Revis. Lamellibr. i Nilsson’s Petrific. Suecana Format. Cret.’ (1897), p. 62, pl. iii, fig. 28; Ravn, ‘ Mollusk. i Danmarks Kridtafl. I. Lamellibr.’ (1902), p. 65 [133], pl. iv, fig. 24. * *Petref. Germ.,’ vol. ii (1840), p. 251, pl. cli, tig. 17. Compare also Wollemann, ‘Senons v. Biewende’ (‘Jahrb. d. k. preuss. geol. Landesanst.,’ fiir 1900), p. 28, fig. 5; Miller, ‘ Mollusk. d. Untersen. v. Braunschweig u. Ilsede’ (1898), p. 77, pl. x, figs. 10,11; Wollemann, ‘ Fauna der Liine- burg. Kreide’ (1902), p. 80. 5 *Paleont. Indica, Cret. Fauna S. India,’ vol. iii (1870), p. 41. 262 CRETACEOUS LAMELLIBRANCHIA. Family—PERNIDA, Zittel. (Continued from page 95.) Genus—InocrraAmus, J. Sowerby,’ 1819. (J. Parkinson [ex Sowerby MS.], ‘Trans. Geol. Soc.,’ ser. 1, vol. v, 1819, p. 55. J. Sowerby, ‘Trans. Linn, Soc.,’ vol. xiii, 1822, p. 455.) InoceraMus NeocomiEnsis, @’Orbigny, 1846. Plate XLV, figs. 1, 2. 1846. Inoceramus neocomiensts, A. d’Orbigny. Pal. Franc. Terr. Crét., vol. i, p. 503, pl. cceciii, figs. 1, 2. 1850. — — d’Orbigny. Prodr. de Pal., vol. 11, p. 83. 1854. — — J. Morris. Cat. Brit. Foss., ed. 2, p. 170. 1855. = == G. Cotteau. Moll. Foss. de l’Yonne, p. 107. 1869. — — FJ. Pictet and G. Campiche. Foss. Terr. Crét. Ste. Croix (Matér. Pal. Suisse, ser. 5), p. 104. 1900. -— -— A. Wollemann. Die Bivalvy. u. Gastrop. d. deutsch. uu. holliind. Neocoms, p. 60. 2 1905. = = EH. Harbort. Die Fauna d. Schaumburg- Lippe’schen Ireidemulde, p. 44, pl. ix, figs. 4-6. Description.—Shell inequivalve, very inequilateral, a little higher than long. Valves convex, with flattened sides, and the posterior part compressed. Anterior margin nearly straight; posterior and ventral margins rounded. Posterior margin forming an obtuse angle with the hinge-line. Anterior part nearly perpendicular to the plane of the valves and excavated near the umbones. Umbones terminal, curved inwards and forwards. Hinge-line equal to more than half the height of the shell, and making an angle of about 100° with the anterior margin. Ornamentation consists of narrow, regular, concentric ribs with an unsym- metrical curvature; the interspaces are broad and regularly concave. 1 Tn rearranging the collection of Inocerami in the British Museum, Mr. R. B. Newton and Mr. C. D. Sherborn have found several type-specimens, the existence of which had not been previously recognised ; this discovery has greatly facilitated my work. I am also indebted to Mr. Newton and. Mr. Sherborn for assistance in selecting specimens for figuring. I wish to thank Mr. C. P. Chatwin for information respecting the zonal distribution of the species of Inoceramus in the Chalk and for other assistance. Dr. Blackmore, Dr. Rowe, and Mr. G. E. Dibley have helped by the loan of numerous specimens from their collections. INOCERAMUS. bo oe) Affinities.—See I. anglicus (p. 264). I, neocomiensis appears to be allied to 1. Hiwaldi, Schliiter,! of which only one figure has yet been published. The differences seen are in the greater relative height, the more inequilateral form, and the greater convexity of the curve of the ribs of I. neoconiensis.* Remarks.—This species was first recorded in England by Fitton. Only a few specimens have been seen; they agree fairly well with @Orbigny’s figure, but the ribs appear to be better defined, and usually the posterior ear-like part is less distinctly limited. The English specimens are not sufficient to show whether the inequality of the valves is as great as in @’Orbigny’s figure. T'ype.— Prof. Boule informs me that d’Orbigny’s figures are restorations based on two specimens from the Barremian of Bettancourt. The types are in the Natural History Museum, Paris. Distribution.—Lower Greensand (Fitton’s Bed 13) of Atherfield. Hythe Beds of Lympne. Lower Greensand of Nutfield. INOCERAMUS, Sp. A few specimens of Inoceramus, not sufficiently perfect for description, have been found in the Speeton Clay (zone of Belemnites lateralis) and in the Spilsby Sandstone of Holton and Acre House. Inoceramus Satomont, @’Orbigny, 1850. Plate XLV, figs. 8—7. 1850. Inocrramus Satomont, A. d’Orbigny. Prodr. de Pal., vol. ii, p. 139. 1853. — --- FJ, Pictet and W. Roux. Moll. Foss. Gres verts de Genéve, p. 501, pl. xli, fig. 3. 1855. — — G. Cotteau. Moll. Foss. de ’Yonne, p. 107. 1869. — _- F. J. Pictet and G. Campiche. Terr. Crét. Ste. Croix (Matér. Pal. Suisse, ser. 5), p. 109, pl. clx, figs. 5—8. Description.—Left valve inflated, subquadrate, very inequilateral. Length and height nearly equal. Anterior half of valve very convex ; posterior half compressed. Anterior end of valve more or less nearly perpendicular to the plane between the valves, and concave near the umbo. Umbo anterior, prominent, pointed, incurved. 1 See footnote on p. 267. 2 Compare also forms described by Schmidt as allied to I. neocomiensis, ‘Mém. Acad. Imp. Sci. St. Pétersb.,’ ser. 7, vol. xviii (1872), pp. 155—161, pl. ii, fig. 8, pl. i, figs. 6—9. 264. CRETACEOUS LAMELLIBRANCHIA. A broad, usually shallow sulcus extends from below the umbo to the ventral margin, where it produces a slight sinuosity ; usually the sulcus starts at some distance from the umbo, and may consequently be absent in small specimens. Ornamentation consists of small, narrow, somewhat irregular concentric ribs, separated by broad, shallow, concave interspaces. Affinities—This species is related to I. concentricus, Parkinson, but is dis- tinguished by its subquadrate outline, by the length and height being nearly equal, and by the presence of the sulcus. Remarks.—All the specimens seen are internal casts of left valves. The examples figured by Pictet and Roux and by Pictet and Campiche are also left valves. Type. D’Orbigny’s specimens came from the Albian of Novion, Clar, Géraudot, and Saint Florentin. Distribution. — Manmillatus bed of Copt Point, Folkestone. INOCERAMUS ANGLICUS, sp. nov. Plate XLV, figs. 8—10. Text-fig. 29. 1822. Inocreramvus, sp., G. Mantell. Foss. 8. Downs, p. 96, pl. xix, fig. 20. 1859. — Crispit, T. Wiltshire. The Red Chalk of England (Geol. Assoc.), p. 16, pl. i, fig. 4. 1875. — concentricus, A. J. Jukes-Browne. Quart. Journ. Geol. Soc., vol. xxxi, p. 299. Description.—Shell equivalve or nearly equivalve, very inequilateral. Anterior part of shell convex, the convexity decreasing with age; posterior part com- pressed, flattened. Anterior slope of valves steep. Anterior margin moderately convex ; ventral margin very convex; posterior margin curved, and forming an obtuse angle with the hinge-line. Length of hinge equal to rather more than a third of the height of the shell. Umbones nearly terminal, with a small anterior curvature. Ornamentation consists of strong, regular, concentric ribs, which have a sub- symmetrical curvature, and become less distinct on the posterior flattened part of the shell. The ribs have rounded summits, and are separated by broad rounded furrows with symmetrical slopes. Some of the ribs bifurcate, some may be dis- continuous, or new ribs may be intercalated. Affinities —The equal size of the valves, the greater convexity of the curve of the ribs, the convex form of the anterior margin, and the outward slope of the anterior part of the valves distinguish this species from I. neocomiensis, dV’ Orbigny (pe 202). INOCERAMUS. 265 I. anglicus also resembles I. Hwaldi, Schliter,’ but is relatively higher, more inequilateral, and the ribs are more strongly curved. Remarks.—This species has been usually identified as I. concentricus, Parkinson, but the equal size of the valves and other characters readily distinguish it from Fia. 29.—Inoceramus anglicus, sp.nov, Red Limestone, Hunstanton. Sedgwick Museum, Cambridge. Part of right valve. Natural size. that species. An example from Hunstanton was figured by Wiltshire as IL. Ovispii (= Crippsi), Mantell. Distribution—Red Limestone of Hunstanton. Gault of Folkestone. Cam- bridge Greensand (derived from the Gault). Marlin the Gault of Roydon, West Norfolk. Upper Greensand of Haldon, the Isle of Wight, and Devizes. INOcCERAMUS ConcENTRICUS, Parkinson, 1819. Plate XLV, fig. 11; Plate XLVI, figs. 1105 Plate XUVUG fies. 12: 1819. Inocrramus concrentrRicus, J. Parkinson. Traus. Geol. Soc., ser. 1, vol. v, p. 58, pl. 1, fig. 4. 1821. — — J. Sowerby. Min. Conch., vol. iii, p. 183, pl. ecev, figs. 1—6. 1822. — — G. Mantell. Foss. S. Downs, p. 95, pl. xix, fios. 15, 19. —_ = = A. Brongniart in Cuvier, Ossemens Foss., vol. 1, pt. 2, pp. 333, 336, 609; plana, fics LE: 1828. — GRYPHHOIDES, J. de C. Sowerby. Min. Couch, vol. vi, p. 161, pl. dlxxxiv, fig. 1. 1 See footnote on p. 267. 266 CRETACEOUS LAMELLIBRANCHIA. 1833. Carriius pyrirormis, H. Michelin. Magasin de Zoologie, iii, Classe 5, pl. XXX1. 1836. Lyocrramus concrentricus, A. Coldfuss. Petref. Germ., vol. i, p. 111, pl. cix, figs. 8a, b, ¢, (non 8d, e, f). ? 1842. —- — P. Matheron. Catal. Foss. des Bouches-du- Rhone, p 173. 1846. - — A. @Orbigny. Pal. Frang. Terr. Crét., vol. iii, p. 506, pl. ececiv. = — A. Leymerie. Statist. geol. et min. de l Aube, Atlas, pl. v, fig. 12. 1850. - H. B. Geinitz. Das Quadersandst. oder Kreide- geb, in Deutschland, p. 174. = = A. @Orbigny. Prodr. de Pal., vol. 1, p. 138. 1853. = = FJ. Pictet and W. Roux. Moll. Foss. Grés verts de Geneve, p. 500, pl. xlii, fig. 2. 1854 = = J. Morris. Cat. Brit. Foss., ed. 2, p. 169. — arypHmoipEs, J. Morris. Ibid., p. 169. 1855. ~— concEntRIcus, G. Cotteau. Moll. Foss. de ’Yonne, p. 107. 1869. -- —- F. J. Pictet and G. Campiche. Terr. Crét. Ste. Croix (Mater. Pal. Suisse, ser. 5), p. 107. 1876 ~~ ~ J. F. Whiteaves. Mesozoic Fossils (Geol. Surv. Canada), vol. i, pp. 79, 241. 1877. = = C. Schliiter. Paleontographica, vol. xxiv, p. 255. -- — — G. Bohm. Zeitschr. d. deutsch. geol. Gesellsch., vol. xxix, p. 238. 1897 - Rk. B. Newton. Proc. Dorset Nat. Hist. and Antiq. Field Club, vol. xviii, p- 88, pl. iii, fig. 12. 1906. A. Wollemann. Jahrb. d. k. preuss. geol. Landesanst. fiir 1906, vol. Xxvil, p. 2/1. Non 1837. — G. Fischer de Waldheim. Oryctogr. de Mos- cou, p. 177, pl. xx, figs. 1—3. (= Aucella Keyserlingiana, Trautschold). 1841. = = F. A. Rimer. Die Verstein d. nord-deutsch. Kreidegeb., p. 61. 1845. E. Forbes. Quart. Journ. Geol. Soc., vol. 3, p. 247 (I. neocomiensis, d’Orb.) — 1846. -- = A. H. Reuss. Die Verstein. der bohm. Kreide- format., pt. 2, p. 24. — (1847. aE = J. Miller. Petref. der Aachen. Kreidef., pt. 1, p: 30. INOCERAMUS. 267 Non 1875. Inocrramus concentricus, A. J. Jukes-Browne. Quart. Journ. Geol. Soc., vol. xxxi, p. 299. Description.—Shell more or less ovate, much higher than long, very mequi- lateral and inequivalve. Anterior part of valves flattened or concave, often more or less nearly perpendicular to the plane between the valves. Posterior part of the valves somewhat expanded and less convex than the part below the umbones. Postero-dorsal part forming a small wing. Left valve very convex, with a high, narrow, pointed, terminal umbo which is considerably incurved and bends forwards. Right valve considerably less convex than the left valve, with a small, terminal umbo curved forwards but only shehtly inwards. Hinge-line less than half the height of the shell. When the shell is perfect the surface is nearly smooth except for numerous reeular growth-rings. When the outer layer of the shell is wanting concentric undulations or ribs having an unsymmetrical curvature are seen, and are separated by concave furrows. Ajjinities.—I. concentricus has been compared by Wollemann with I. Hwaldi, Schliiter,’ but the prominent umbo and other characters readily distinguish it from that species. See also /. concentricus var. subsulcatus, and I. sulcatus (below). Remarks.—W hilst the left valve in the specimens from the Blackdown Greensand agrees closely with that of specimens found in the Gault, the right valve in many (but not all) cases is relatively more convex, especially between the umbo and the postero-ventral extremity, and the ribs are more sharply curved. A similar modification is seen in the examples from the Red Limestone of Hunstanton. There seems no reason for regarding the specimens with these characters as forming more than a local variety dependent on the fact that they lved under conditions different from those which prevailed where the Gault was deposited. I. gryphexvides, Sowerby, was founded on an internal cast of I. concentricus from the Upper Greensand; in such casts the ribs are more prominent than on the surface of the shell itself. All the examples from the Cambridge Greensand which have been recorded as I. concentricus appear to belong to I. anglicus (p. 264). T'ypes.—The type, which came from the Gault of Folkestone, cannot now be found. The specimens from the same locality figured by Sowerby and by Mantell, and the type of /. gryphexoides from the Upper Greensand near Lyme Regis, are in the British Museum. Distribution.—In all zones of the Gault of Folkestone. Gault of Aylesford, 1 «Monatsber. d. k. preuss. Akad. Wissensch., Berlin’ (1860), p. 345. Schliiter, ‘ Paleeonto- graphica,’ vol. xxiv (1877), p. 255. Wollemann, ‘ Bivalv. u. Gastrop. d. norddeutsch. Gaults”’ (‘ Jahrb. d. k. preuss. geol. Landesanst.,’ vol. xxvii, 1906), p. 272, pl. vi, fig. 9. 268 CRETACEOUS LAMELLIBRANCHIA. Dunton Green (Kent), Black Ven, and Okeford Fitzpaine. Upper Greensand (zone of Schlanbachia rostrata) of Blackdown, Sidmouth, Lyme Regis, and Potterne near Devizes. Limestone in the Gault of West Bilney, Roydon, and Grimston (West Norfolk). Red Limestone of Hunstanton. INOCERAMUS CONCENTRICUS var. suBsULCATUS, Wilishire, 1269. Plate XLVII, figs. o—1 4. 1853. Inoceramus suxtcatus, fF. J. Pictet and W. Roux. Moll. Foss. Gres verts de Geneve, p. 499, pl. xu, figs. 1 d, e, f. 1869. = sussuLcaAtus, 7’. Wiltshire. Quart. Journ. Geol. Soc., vol. xxv, pp. 188, 190. 1879. — — F. G. H. Price. The Gault, p. 54. In the lowest zone of the Upper Gault there occur forms of Inoceramus which differ from I. concentricus only in the fact that radial plications are more or less extensively developed. In these forms every stage can be traced between I. con- centricus without plications into forms in which the plications are almost as complete as in J. sulcatus. A specimen, which differs from I. concentricus only in the occurrence of one shallow plication, is shown in fig. 3 (Plate XLVII); others are similar, but possess two or three plications (Plate XLVI, figs. 4,5). In most cases the early part of the shell agrees entirely with J. concentricus; but the duration of this stage varies considerably in different individuals, and sooner or later either a few or many plications are developed. When the plications are numerous and start from near the umbo the shell closely resembles I. sulcatus, but may usually be distinguished by the rounded (instead of angular) form of the plications, and by the presence of concentric ribs. For these forms, which characterise a definite horizon in the Gault, it will be convenient to adopt as ¢ varietal designation the name subsulcatus, given by Wiltshire in 1869. From a study of many forms of this variety it seems evident that J. sulcatus has been derived from J. concentricus by the gradual development of plications, and this view is in accordance with stratigraphical distribution, since I. concentricus is the earlier of the two species, being found throughout the Gault, whilst J. sulcatus occurs in the upper part of the Gault only. If I. sulcatus has been derived from I. concentricus, then it is clearly more nearly related to that than to any other species of Jvoceramus, and cannot therefore be placed in a separate genus or sub-genus (Actinoceramus), as was proposed by Meek." Further, in the early stages of the variety subsulcatus the shell is a typical 1 «Check List Cret. Foss. N. Amer.’ (‘Smithson. Miscell. Coll.,’ No. 177, 1864), p. 32. Stoliezka, ‘Cret. Fauna 8. India,’ vol. ii (1871), p. 393. Meek and Hayden, ‘Invert. Cret. Tert. Foss. U. Missouri’ (1876), p. 39. INOCERAMUS. 269 Inoceranus, but subsequently it possesses the characters of Actinoceramus. Also it appears that a somewhat similar plication has originated mdependently in J. Salomont (p. 263), and. probably too in J. radians, Schliiter,’ and I. fasciatus, Miller.’ Pictet and Roux regarded subsulcatus as a variety of J. sulcatus in which the number of plications had decreased; the stratigraphical distribution and also the evidence of the extensive series of specimens of subsulcatus which has now been obtained are opposed to this view. Distribution.— Lowest zone of the Upper Gault of Folkestone. Upper Green- sand of Blackdown. Red Limestone of Hunstanton. Inoceramus sutcatus, Parkinson, 1819. Plate XLVI, figs. 15—20. 1819. Inocreramus suucatvs, J. Parkinson. Trans. Geol. Soc., ser. 1, vol. v, p. 59, pl. i, fig. 5. 1821. — — J. Sowerby. Min. Conch., vol. ii, p. 184, pl. ecevi, figs. 1—7. 1822. = -—— G. Mantell. Foss. 8. Downs, p. 95, pl. xix, fig. 16. — = — A. Brongniart in Cuvier. Ossemens Foss., vol. ii, pt. i, pp. 333, 336, pl. vi, fig. 12. 1836. — = A. Goldfuss. Petref. Germ., vol. ii, p. 112, pl. cx, ime, IL, 1837. -- — W. Hisinger. Lethza Suecica, p. 56, pl. xvii, fig. 9. 1846. ~ — A.@Orbigny. Pal. Franc. Terr. Cret., vol. ii, p. 504, pl. eeccin, figs. 3—5. 1850. -- — A.d’Orbigny. Prodr. de Pal., vol. ii, p. 139. 1853. —_ — F.J. Pictet and W. Roux. Moll. Foss. Grés verts de Genéve, p. 499, pl. xlii, figs. la—c (not d-S). 1854. = — J. Morris, Cat. Brit. Foss., ed. 2, p. 170. 1855. - — G.Cotteaw. Moll. Foss. de l Yonne, p. 107. 1864. ActrrnocERAMusS suLcATUS, FI’. B. Meek. Check List Cret. Foss. N. Amer. (Smithson. Miscell. Coll., No. LA) pw oer 1869. Inocrramus suucatus, F. J. Pictet and G. Campiche. Foss. Terr. Crét. Ste. Croix (Matér. Pal. Suisse, ser. 5), p. 105. 1875. —- — A. J. Jukes-Browne. Quart. Journ. Geol. Soc., vol. Xxxi, p. 298. 1877. — — (C. Schliiter. Paleontographica, vol. xxiv, p. 256. 1884. == (ActinocERAMUS) suLcatTus, J. I’. Whiteaves. Mesozoic Fossils, vol. 1 (Geol. Surv. Canada), p. 241, pl. xxxui, fig. 3, 1 ¢ Palwontographica,’ vol. xxiv (1877), p. 270, pl. iii, fig. 2. * «Jahrb. d. k. preuss. geol. Landesanst. fiir’ 1887 (1888), p. 416, pl. xvii, fig. 3. 36 270 CRETACEOUS LAMELLIBRANCHIA. 1906. Inocrramus suncatus, A. Wollemann. Jahrb. d.k. preuss. geol. Landesanst. fiir 1906, vol. xxvii, p. 273, pl. vi, fig. 10. Non 1827. = — . Nilsson. Petrif. Suecana, p. 18. Deseription.—Shell more or less ovate, much higher than long, very inequi- lateral, more or less considerably inequivalve. Anterior part of valves flattened Fia. 30.—Inoceramus, sp. Gault, Folkestone. Sedgwick Museum, Cambridge. Internal cast of right valve. x 4. or concave. Posterior part somewhat expanded and less convex than the part below the umbones. Left valve very convex, with a high, narrow, pointed anterior umbo which is considerably incurved and bends forwards. Right valve rather less convex than the left valve, with a smaller umbo which bends forwards and shghtly inwards. Ornamentation consists of strong angular radial ridges (plications), usually from eight to ten on each valve, which are often unequal in size and are separated INOCERAMUS. 271 by deep furrows. The ridges are often at unequal distances from one another ; some of them start from the umbo, others may be intercalated or may arise by bifureation. Fine concentric lines cover the shell and are folded where they cross the ridges and furrows. Affinities.— Although the radial plications give a distinctive appearance to this species, yet the form of the shell closely resembles that of I. concentricus, the main difference being that in the former the difference in the convexity of the two valves is usually less marked than in the latter. T'ypes.—The type, from the Gault of Folkestone, is in the British Museum. The specimens from near Lewes, Folkestone (except figs. 1 and 2), and Clophill freured by Sowerby, and the specimens figured by Mantell are in the British Museum. Distribution. —Gault of Folkestone, Aylesford, Ringmer, Eastbourne, the Isle of Wight, and Leighton Buzzard. Upper Greensand (zone of Schlenbachia vostrata) of Blackdown, Sidmouth, Black Ven, and Lulworth. Red Limestone of Hunstanton, South Willingham (Lincolnshire), and Speeton. Inoceramus, sp. Text-fig. 30. Specimens of a large, slightly convex Inoceramus are found in the Gault of Folkestone and the Upper Greensand of Potterne (Devizes) and the Isle of Wight, but are not sufficiently perfect for determination. The umbones are terminal, and the hinge-line is nearly at right angles to the anterior margin. The anterior parts of the valves slope steeply to the margin. Small and rather distant concentric ribs are present. This form shows some resemblance to I. pictus (p. 279), but is less convex, and possesses fewer ribs. Inoceramus renvis, Mantell, 1822. Plate XLVIII, fig. 1. Text-figs. 31, 32. 1822. InocERAmus TENUIS, G. Mantell. Foss. 8. Downs, p. 182. 1854. = — J.Morris. Cat. Brit. Foss., ed. 2, p. 170. ? 1859. — — T. Wiltshire. Red Chalk ‘of England (Geol. Assoc.), p. 16, pl. i, fig. 5. 1866. Perna uissa, H. G. Seeley. Ann. Mag. Nat. Hist., ser. 3, vol. xvii, p. 178. Non 1841. JInocrramus tTENuIS? F. A. Rémer. Die Verstein. d. nord-deutsch. Kreidegeb., p. 62, pl. viii, fie. 11. Description.—Shell inequivalve, very inequilateral, convex; postero-dorsal part compressed ; antero-dorsal part excavated and more or less nearly perpen- 272 CRETACHKOUS LAMELLIBRANCHIA. dicular to the plane of the valves; height greater than length. Hinge-line equal to about two-thirds of the height of the shell. Ventral margin very convex ; posterior margin forming an obtuse angle with the hinge-line. Umbones terminal, curved inwards and forwards, the left umbo larger and more prominent than the right. Surface smooth, except for growth-rings. Affinities —I. tenuis resembles I. concentricus, but the left umbo is less Fie. 31.—Inoceramus tenwis, Mantell. Chalk Marl, Hamsey. The type, No. 5890, British Museum (Nat. Hist.). The specimen is somewhat compressed from front to back. Left valve and anterior view of both valves. Right valve shown in the next figure. prominent, the length of the shell is relatively greater, and the concentric rings are less prominent. The fragmentary specimens described by Seeley as Perna Lissa appear to belong to this species.' Types.—In the British Museum (No. 5890) from the Chalk Marl of Hamsey. A fragment, from the Red Limestone of Hunstanton, which appears to be one of 1 The form from the Red Limestone of Hunstanton which was named Perna transversa by Seeley is at present known only by an imperfect left valve. It is perhaps allied to I. tenwis, but is remark- able in being much longer than high. The type is in the Sedgwick Museum, Cambridge. Seeley, ‘Ann. Mag. Nat. Hist.,’ ser. 3, vol. xvii (1866), p. 179. INOCERAMUS. 273 the specimens on which Seeley’s description of Perna lissa was based, is in the Sedgewick Museum, Cambridge. Fie. 32.—Inoceramus tenwis, Mantell. Right valve. See Fig. 31. Distribution.—Red Limestone of Hunstanton, Louth, and Speeton. Upper Greensand of Ventnor and Potterne. Chalk Marl of Hamsey. Inoceramus Criprsi, Mantell, 1822. Plate XLVIII, figs. 2,3. Text-figs. 33—35. 1822. Inoceramus Cripsit; G. Mantell. Voss. 8. Downs, p. 133, pl. xxvii, fig. 11. 1836. — Latus, A. Goldfuss. Petref. Germ., vol. 11, p. 117, pl. exii, fig. 5 (non Mantell). 1846. a — A.d@Orbigny. Pal. Franc. Terr. Crét., vol. iii, p. 513, pl. ceceviii, figs. 1, 2. 1854. =<é Crispi, J, Morris. Cat. Brit. Foss., ed. 2, p. 169. 1904. — LAtus, H. T. Newton and A. J. Jukes-Browne. In Jukes- Browne, Cret. Rocks of Britain, vol. 1, p. 449. 1909. —- Crrppst, J. Bohm. Subhereyn. Kreidemulde (Abhandl. d. k. preuss. geol. Landesanst., N.F., 56), p: 405 pli ax, fie bo AT — Non 1822. = 828) 18386. — 1840. 1841. — 1866. CRETACEOUS LAMELLIBRANCHIA. InocrerAmus Latus, G. Mantell. Foss. 8. Downs, p. 216, pl. xxvu, fig. 10. — J. de C. Sowerby. Min. Conch., vol. vi, p. 159, pl. dixxxar, fig) 1 Crispi, A. Goldfuss. Petref. Germ., vol. ii, p. 116, pl. exii, fig. 4. — 4H. B. Geinitz. Char. d.Schicht. u. Petref. des sichs. Kreidegeb., pt. 1, p. 27. LATus, fF’. A. Rimer. Die Verstein. d. nord-deutsch. Kreidegeb., p- 61. Cripsi, Rimer. Ibid., p. 63. — 4H. B. Geinitz. Grundr. d. Verstein., p. 464. Latus, Geinitz. Ibid., p. 463. — A. H. Reuss. Die Verstein. der bohm. Kreideformat., pt. 2, p. 25. Criesil, Reuss. Ibid., p. 25, pl. xxxvii, figs. 10, 12. — J. Miiller. Petref. der Aachen. Kreidef., pt. 1, p. 30. — F. Romer. Kreidebild. v. Texas, p. 56, pl. vii, fig. 2. LAtus, Romer. Ibid., p. 60. Crispit, 7’. Wiltshire. Red Chalk of England (Geol. Assoc.), p. 16, pl. i, fig. 4. Cripst, A. v. Strombeck. Zeitschr. d. deutsch. geol. Gesellsch., vol. xv, p. 152. — K.A. Zittel. Bivalv. d. Gosaugeb., ii (Denkschr. d.k. Akad. Wissensch , Wien, Math.-nat. Cl., vol. xxv), p. 95, pl. xiv, figs. 1—5, pl. xv, figs. 1—5. uaTus, Zittel. Ibid., p. 100, pl. xii, fig. 7. Cripst, HL. Favre. Moll. Foss. de la Craie de Lemberg, p. 132. LAtus, I’. Rémer. Geol. Oberschles., p. 316, pl. xxxiv, fig. 12. Cripsit, Romer. Ibid., p. 356, pl. xxxix, fig. 9. Crispranus, IF. Stoliczka. Paleont. Indica, Cret. Fauna 8. India, p. 405, pl. xxvii, figs. 1—3, pl. xxviii, fig. 2 (mot pl. xxvil, fig. 3, I. Heberti, Fallot). Cripst, H. B. Geinitz. Das Elbthalgeb. in Sachsen (Pal- eontographica, vol. xx, pt. 2), p. 49, pl. xiii, figs. 11-15. LATUS, Geinitz. Ibid., p. 45, pl. xiii, figs. 4, 5. — Geinitz. Neues Jahrb. fiir Min., etc., p. 11. Cripst, Geinitz. Ibid., p. 16. LatTus, CU. Décocg. Assoc. Franc. Avance. Sci. (Lille), p. 369. Cripsi, D. Brauns. Zeitschr. f. d. gesammt. Naturwissenscb., vol. xlvi, p. 378. — Y var. Barapini, Ff. B. Meek. Invert. Cret. Tert. Foss. U. Missouri, p. 49, pl. xii, fig. 3, pl. xiii, fig. 1. — ?vyar. suspunDATUS, F’. B. Meek. Bull. U.S. Geol. and Geogr. Surv. Territories, vol. ii, p. 3858, pl. iu, figs. 1, 3. Non 1877. — 1878. — 1879. — 1894. — 19083. INOCERAMUS. 275 Inocreramus Cripestt, C. Schliiter. Paleeontographica, vol. xxiv, p. 277. == Latus, C. Barrois. Ann. Soe. géol. Nord, vol. v, pp. 407, 475. - CRIPSII, vars. PROXIMUS, SUCIENSIS, BArABINI, J. F'. Whiteaves. Mesozoic Foss., vol. i (Geol. Surv. Canada), pp. 172—174. — — H. Schrider. Zeitschr. d. deutsch. geol. Gesellsch., vol. xxxiv, p. 273. — Cripsi, EH. Fallot. Ann. Sci. géol., vol. xviii, p. 250. = Cripsu, A. Peron. Hist. Terr. Craie 8.E. du Bassin Anglo- Parisien, p. 158, — — G. Miller. Jahrb. d.k. preuss. geol. Landesanst. fiir 1887, p. 416. = — . Holzapfel. Die Mollusk. Aachen. Kreide (Paleon- tographica, vol. xxxv), p. 222. -— Cripst, A. Fritsch. Stud. im Gebiete der bohm. Kreide- format., iv, Teplitz. Schicht., p. 82, fig. 73. — O. Griepenkerl. Senon. v. Konigslutter (Paleont. Abhandl., vol. iv), p. 50. = Cripsit, J. Bohm. Paleeontographica, vol. xxxvui, p. 81. a — K. Futterer. Ober. Kreidebild. St. Croce (Palwont. Abhandl., vol. vi), p. 80. — Cries, H. Stolley. Kreide Schleswig-Holsteins (Mittheil. Min. Instit. Universit. Kiel, vol. 1), p. 241. == Crippst, B. Lundgren. Mammilatus och Mucronata zonerna (K. Svenska Vet.-Akad. Huandl., N.F., vol. xxvi, No. 6), p. 45. — Criesit, R. Leonhard. Palseontographica, vol. xliv, p. 49. — Latus, Leonhard. Ibid., p. 49. == Cripsu, G. Miller. Mollusk. Untersen. v. Braunschweig u. Ilsede (Abhandl. d. k. preuss. geol. Landesanst., n.¥., 25), p. 45, fig. 12. — —— G. de Alessandri. Paleont. Ital., vol. iv, p. 194, pl. xvi, fig. 9. -— Latus, Alessandri. Ibid., p. 196. _ Cripst, A. Wollemann. Jahrb. d. k. preuss. geol. Landesanst. fiir 1900, vol. xxi, p. 18. == Latus, fF. Sturm. Ibid., vol. xxi, p. 93, pl. x, fig. 2. — Cripsi, H. Imkeller. Palseontographica, vol. xlviii, p. 33. == — var. RADIOosA, A. Quaas. Ibid., vol. xxx, 2, p. 170, pl. xx, figs. 9, 10. = — A. Wollemann. Luneburg. Kreide (Abhandl. d. k. preuss. geol. Landesanst., N.F., 37), p. 72. a Larus, W. Petrascheck. Jahrb. d. k. k. geol. Reichsanst., vol. li, p. 165. 276 CRETACEOUS LAMELLIBRANCHIA. Non 1905. Inocrramus Crips, 7. Wegner. Zeitschr. d. deutsch. geol. Gesellsch., vol. Ivii, p. 161. 1906. — Crispianus, J. Pethi. Palawontographica, vol. li, p. 232. 1908. — Cripsit, A. Stojanof. Ann. géol. min. Russie, vol. x, p. 121. Descrviption.—Shell thin, equivalve, moderately imequilateral, convex between the umbo and the ventral margin ; postero-dorsal part compressed and flattened ; antero-dorsal marginal part nearly perpendicular to the plane of the valves and Fia. 33. Fie 34. Fia.33.—Inoceramus Crippsi, Mantell. The type, British Museum (Nat. Hist.) No. 5893. Chalk Marl, Oftham. Internal cast. Natural size. iis: Fria. 34.—Inoceramus Crippsi, Mantell. Chalk Marl. Internal cast of a left valve similar to the type. British Museum (Nat. Hist.) No. 5895. Natural size. nearly straight. Ventral margin convex; posterior margin only slightly convex, and forming more than a right angle with the hinge-lne. Huinge-line forms an angle of about 140° with the antero-dorsal margin. Umbones inconspicuous, pointed, not curved, at about a third of the length of the hinge from the anterior end; in front of the umbones is a small, obtusely triangular ear. Ornamentation consists of broad, rounded, rather irregular concentric ribs, which are strong anteriorly, and become weaker posteriorly. ‘The curvature of the ribs is unsymmetrical; the anterior part curves rapidly, the postero-dorsal part is only shehtly curved. Affinities —A species from the Senonian was figured and described by Goldfuss INOCERAMUS. 207 as I. Orippsi, Mantell,and that identification has been accepted by many later writers. The type of I. Crippsi came from the Chalk Marl (zone of Schleenhachia varians). From a study of a cast of the type, Petrascheck and J. Bohm!’ came to the conclusion that the Senonian species is quite distinct from I. Crippsi, and Bohm has named the former J. balticus. Bohm also supports the view first suggested by Messrs. E. T. Newton and A. J. Jukes-Browne, and confirmed by Fie. 35.—Inoceramus Crippsi, Mantell. Upper Greensand, Haldon. Right valve. British Museum (Nat. Hist.), No. 17201. Natural size. Petrascheck, that I. latus of Goldfuss and of @Orbigny (but not of Mantell) is identical with J. Crippsi, Mantell. After a careful study of the type and other similar specimens of I. Crippsi, and of specimens of J. latus, I can fully support these conclusions. I. cunetformis, d Orbigny,’ is allied to I. Crippsi, but is relatively higher. One specimen found in the Upper Greensand of Warminster (Plate XLVIII, fig. 3), 1 «Subhercyn. Kreidemulde ’ (1909), pp. 41—46; Petrascheck, “ Inoceram. a. d. Gosau,” ‘Jahrb. d. k. k. geol. Reichsanst.,’ vol. lvi (1906), p. 155. 2 «Pal. Frane. Terr. Crét.,’ vol. 111 (1846), p. 512, pl. eccevii. 37 278 CRETACEOUS LAMELLIBRANCHIA. shows some resemblance to L. cuneiformis, but is probably only a rather high form of I. Orippsi, with which species it is found associated. I. orbicularis, Goldfuss,' is regarded by B6hm as a small form of I. Crippsi, Mantell. T'ype.—In the British Museum (fig. 33) from the Chalk Marl (zone of Schlan- bachia varians) of Offham. Distribution.—Upper Greensand of Haldon. Upper Greensand (zone of Pecten asper) of Warminster and Devizes. Chalk Marl (zone of Schlanbachia varians) of Ringmer, Hamsey, Offham, Maiden Newton, Eggardon Hill, Pyrton, Chalton, Arlesey, Hunstanton, and Donnington (Lincolnshire). Cenomanian of Wilmington (Devon). Lower Chalk (zone of Holaster subglobosus) of Totternhoe, Burham, and Cherry Hinton. INocERAMUS Crippst var. REACHENSIS, Htheridge, 1881. Plate XLVILI, figs. 4, 5; Plate XLIX, fig. 1. 1881. InocERAMUS LATUS Var. REACHENSIS, R. Htheridge. In Penning and Jukes- Browne, Geol. Cam- bridge, p. 142, pl. i, fig. 3. Remarks.—In this form, which is mainly characteristic of the zone of Holaster subglobosus, the ribs are more sharply defined, their ventral curvature is greater, and their posterior part is less nearly straight than in J. Crippsi. Type-—From the Totternhoe Stone of Burwell, in the Sedgwick Museum, Cambridge. Distribution.— Chalk Marl of Blue Bell Hill, Burham. Zone of Holaster sub- globosus of Merstham and Blue Bell Hill, Burham. ‘Totternhoe Stone (zone of H., subglobosus) of Burwell. Recorded by Etheridge from the Chall Marl of Reach. Inoczramus Erueripcrl, nom. nov. Plate XLIX, figs. 2—4. 1881. Inoceramus convexus, R. Etheridge. In Penuing and Jukes-Browne, Geol. Cambridge, p. 143, pl. i, fig. 6. — = var. QUADRATUS, Htheridge. Ibid., p. 143, pl. u, fig. 7. == = STRIATUS Var. CONVEXUS, A. J. Jukes-Browne. Cret. Rocks of Britain, vol. ii, p. 476. “1 © Petref. Germ.,’ vol. ii (1836), p. 117, pl. exiii, fig. 2. Bohm, ‘ Subhereyn. Kreidemulde’ (1909), p. 46, pl. xi, fig. 1. INOCERAMUS. 279 Non 1855. Inocrramus convexus, J. Halland F. B. Meek. Foss. Cret. Nebraska (Mem. Amer. Acad. Arts and Sci., vol. v), p. 886, pl. ii, fig 2. Description.— Valves nearly equal, considerably inequilateral, tumid, compressed near the postero-dorsal margin ; height greater than length. Antero-dorsal margin nearly straight; ventral margin usually very convex ; posterior margin slightly or moderately convex, forming an obtuse angle with the hinge-lne. Anterior marginal parts more or less nearly perpendicular to the plane of the valves, some- times concave near the umbo. Umbones terminal, curved inwards and forwards. Angle between the hinge-line and the anterior margin is about ioe. ‘The height of the shell is nearly twice the length of the hinge. Ornamentation consists of faintly marked concentric undulations and numerous erowth-lines. Afjinities.—In this species the antero-dorsal margin is relatively longer and more nearly straight, and the postero-dorsal part of the shell less compressed than in I. tenuis, Mantell. 1. conveaus var. quadratus, Etheridge, was founded on a specimen in which the anterior part of the shell is pressed in, giving rise to the appearance of a carina at the upper margin of the antero-dorsal slope. T'ypes.—From the Totternhoe Stone of Burwell, in the Sedgwick Museum, Cambridge. Distribution.-Upper Greensand (zone of Pecten asper) of Warminster. Cenomanian of Wilmington, Devon. Chalk Marl of Branscombe, Beer Head, Titherleigh (near Chard) and Hunstanton. Totternhoe Stone (zone of Holaster subglobosus) of Burwell. Tnoceramus picrus, Sowerby, 1829. Plate XLIX, figs. 5,6. Text-fig. 36. 1829. Inocrramus Picivs, J. de C. Sowerby. Min. Conch., vol. vi, p. 215, pl. deiv, fig: Ii, 1854. — pictus, J. Morris. Cat. Brit. Foss., ed. 2, p. 170. 1867. — anauLatus, HL. Guéranger. Album Paléont. de la Sarthe, p. 20, pl. xxv, fig. 7 (? I.anauLatus, d Orbigny, 1846). 1904. — pictus, . T. Newtonand A.J.Jukes-Browne. In Jukes-Browne, Cret. Rocks of Britain, vol. ii, p. 450. Description.—Shell equivalve, very inequilateral, shghtly or moderately convex with flattened sides; the postero-dorsal part compressed. Antero-dorsal marginal 280 CRETACEOUS LAMELLIBRANCHIA. part flattened or concave, and more or less nearly perpendicular to the plane of the valves. Ventral margin very convex; posterior margin moderately convex. Umbones terminal, incurved. Huinge-line nearly at right angles to the anterior margin. Ornamentation consists of numerous strong, somewhat irregular concen- tric ribs, separated by concave interspaces. The curvature of the ribs is unsymmetrical, and the ribs become less distinct on the antero-dorsal and postero- dorsal parts of the valves. Affinities.—This species shows some resemblance to I. anglicus, but possesses more numerous ribs, and also differs in the anterior part of the shell being flat or Fic. 36.—Inoceramus pictus, Sow. Chalk Marl, Guildford. British Museum No. 43272. The Type. Natural size. concave. The type and some other specimens (e.g. No. 738339, British Museum) show traces of the original colouring of the shell. An example of this species was figured by Guéranger as J. angulatus, d’Orbigny,' but appears to be quite distinct from that form. Type.—¥rom the Chalk Marl of Guildford, in the British Museum (Natural History). Distribution.—Lower Chalk (zone of Holaster subglobosus) of Beachy Head, Burham, Rochester, and the Gog-ma-goes, near Cambridge. Chalk Marl of Burham and Guildford. 1 «Pal. Frang. Terr. Crét.,’ vol. iii (1846), p. 515, pl. ecceviii, figs. 3,4. In the text the spelling is angulosus. Inoceramus LABratus (Schlotheim), 1815, 1768. INOCERAMUS. 281 Plate L. Text-fig. 37. Osrracites, J. H. I. Walch. Die Naturgesch. Verstein z. Erliut. d. Knorrischen Sammi. v. Merkwiirdigk. d. Natur: EL p. 845 pl EEb*, fie. 2. p. 152, pl. dx, figs. 1, 2. In Leonhard’s Taschenbuch fiir Min., vol. vii, p. 93. Priynites piLuvianus, Schlotheim. Ibid., p. 93. Schlotheim. Petrefactenk., p. 303. Myrruorpes tasratus, A. Brongniart. In Cuvier, Ossemens Fossils, vol. ii, pt. 2, pp. 820, 597, pl. iu, fig. 4. Foss. S. Downs, p. 215, pl. xxvii, == LABIATUS, LH. F. v. Schlotheim. INOcERAMUS MYTILLOIDES, G. Mantell. fig. 3; pl. xxviii, fig. 2. = mMyTILoIpEs, J. de C, Sowerby. Min. Conch., vol. v, p. 62, pl. cecexlii (not the two smaller figures). Petrif. Suecana, p. 19. Petret. Germ.,, vol. u, p. 118; spl. exil, fig. 4. Polens Paliont., p. 45. Die Verstein. d. nord-deutsch. CatitLumM ScHiLoTHeEIMI, S. Nilsson. InocERAMUS MyTILOIDES, A. Goldfuss. CaTILLUS MyTILOIDES, G. G. Pusch. InNocERAMUS MyTILOIDES, F’. A. Rimer. Kreidegeb., p. 63. — PROBLEMATICUS, A.d’Orbigny. Pal. Franc. Terr. Crét., vol. 1, pp. olO> pl veceevin figs: 1—7 (Non. I. problematicus, v. Schlotheim). — MYTILOIDES, A. H. Reuss. Die Verstein. der bohm. Kreide- format., pt. 2, p. 26, pl. xxxvil, fie. 16. Grundr. d. Verstein., p. 463. Mém. Soc. géol. de France, ser. 2, vol. ii, p. 307. — PROBLEMATICUS, A. d’Orbigny. Prodr. de Pal., vol. 11, p. 197. Das Quadersandst. oder Kreide- geb. in Deutschland, p. 176. H. B. Geinitz. = A. @ Archiac. = MyTILOIDES, H. B. Geinitz. — — F. Romer. Kreidebild. v. Texas, p. 60, pl. vii, fie. 5. — —- J. Morris. Cat. Brit. Foss., ed. 2, p. 170 (partin). = — A. v. Strombeck. Zeitschr. d. deutsch. geol. Gesellsch., vol. xv, p. 119. Geol. v. Oberschles., p. 316, pl. xxxiv, fig. 12. Paleont. Indica, Cret. Fauna S. India, vol. ii, p. 408, pl. xxix, fig. 1. = Latus, I’. Romer. = LABIATUS, IF. Stoliczka. 282 CRETACEOUS LAMELLIBRANCHIA. 1872. Inocrramus Laprarus, H. B. Geinitz. Das Elbthalgeb. in Sachsen (Pal- zontographica, vol. xx, pt. 2), p. 46, pl. xi, figs. 1—3. 873. = Geinitz. Neues Jahrb. fiir Min, etc., p. 13. 1877. — C. Schliiter. Palseontographica, vol. xxiv, p. 262. = a : A. Fritsch. Stud. im Gebiete der béhm. Kreide- format. 11, Weissenberg. u. Malnitz. Schicht., p. 130, fig. 112. ? 1888. -— ~~ S. Nikitin. Les Vestiges Crcét. Russ. centrale (Mém. Comité géol. Russ., vol. v, no. 2), p. 34, pl. 5, figs. 10, 11. 1888. — = A. Peron. Hist. Terr. de Craie dans le S.E. du Bassin Anglo-Parisien, p. 158. 1893. — — R. Michael. Zeitschr. der deutsch. geol. Gesellsch., vol. xlv, p. 241. = = . T. W. Stanton. The Colorado Formation (Bull. U.S. Geol. Surv., No. 106), p. 0; plex, ee Ae pl, xaveio. 2: ? 1897. = ae R. Leonhard. Kreideformat. in Oberschles. (Pal- seontographica, vol. xliv), p. 48. 1903. = _ W. Petrascheck. Jahrb. d. k. k. geol. Reichsanst., vol. li, p. 156. ? Non 1868. -— MYTILOIDES, H’. Hichwald. Letheea Rossica, vol ii, p. 492, pl. Xx; fie. 6. -— 1881. — (Myrrnires) propLeMAticus, R. Etheridge. In Penning and Jukes-Browne, Geol. Cambridge, p. 143, pl. iii, figs. 9-—11. Description.—Shell mytiliform, nearly equivalve, extremely imequilateral, oblique, much elongated between the umbo and the postero-ventral extremity, convex, with a small posterior ear; antero-dorsal part sloping steeply and some- times concave. Angle formed by the hinge with the antero-dorsal margin about 90°. Umbones terminal, with a slight anterior curvature. Anterior margin gently curved ; postero-ventral extremity very convex; posterior margin nearly straight. Ornamentation consists of small, fairly regular concentric undulations, which have an unsymmetrical curvature in the young, but become more nearly symmetrical in older specimens. On the old parts of the shell the undulations become less distinct. Affinities —It seems probable that this species is related to I. Crippsi var. reachensis (p. 278), but the height of the shell is relatively greater, the length of the hinge-line is less, and the direction of growth is oblique to the hinge-line. I. propinquus, Goldfuss,' from the Quader-sandstone of Schandau, was regarded by Geinitz as a synonym of I. labiatus. I“ Petre. Germ.,’ vol. 1 (1836) p. 112, pl. cix, fig. 9. INOCERAMUS. 283 D’Orbigny identified this species with IL. problematicus, von Schlotheim, which comes from the Senonian, and has been shown by Bohm to be distinct from the Turonian form.' Remarks.—This species is mainly characteristic of the zone of Rhynchonella Cuviert. In the zone of Terebratulina lata it is not common, and the shell is usually relatively longer than in typical forms of the species. T'ypes.—The type came from the Turonian of Pirna. The specimens figured by Mantell from the zone of Rhynchonella Cuvieri of Plumpton are in the British Museum. The large specimen figured by Sowerby from Warminster cannot be found. Distribution.—Zone of Rhynchonella Cuviert of the Devon and Dorset coasts, the Isle of Wight, Winchester, Eastbourne, Lewes, Plumpton, Dover, Blue Bell Hill (Burham), Betchworth, Watlington (Berkshire), Hitchin, Cherry Hinton, South Thoresby, South Ferriby (Lincolnshire), and the Yorkshire coast. Zone of Terebratulina lata of the Devon and Dorset coasts, Winchester, Eastbourne, and Dover. Recorded by Jukes-Browne from the zone of Holaster subglobosus of Cambridge- Fie. 37. Fig. 38. Fia. 37.—Inoceramus labiatus (Schloth). The type of Inoceramus mytiloides, Mantell, ‘Foss. 8. Downs? p. 215, pl. xxviii, fic. 2. Zone of Rhynchonella Cuvieri, Plumpton. British Museum, Natural size. Fia,. 38.—Inoceramus labiatus var. latus, Sow. Zone of Holaster planus, Purley Junction Station Baitish Museum, No. L21194. Natural size. : ; ' J. Bohm, ‘ Monatsber. d. deutsch, geol. Gesellsch.’ (1909), p. 117. 284: CRETACEOUS LAMELLIBRANCHIA. shire and West Norfolk ; and by Rowe from the zone of Holaster planus of Dover and the Sussex coast, and from the zone of Micraster cor-testudinarium of Dover. Fia. 39. Fia. 40. » * ae _———— — SN a a, Ee ea Fig. 39.—Inoceramus labiatus var latus, Sow. Zone of Holaster planus, Swaftham, Norfolk. Norwich Museum, No. 3296. Right valve and anterior view. Natural size. Fie. 40.—Inoceramus labiatus var. latus, Sow. One of the types of Inoceramus latus, Sowerby, ‘ Min. Conch.,’ vol. vi, p. 159, pl. dlxxxii, fig. 1 (lower figure). Swaffham. British Museum, No. 43266. Natural size. INOCERAMUS LABIATUS var. LATUS, Sowerby, 1828. Text-figs. 388—40. 1828. Inocrramus uarus, J. de C. Sowerby, Min. Conch., vol. vi, p. 159, pl. dixxxn, fig; dW: (Non F latue; Mantell). 1854. _ — J. Morris. Cat. Brit. Foss., ed. 2, p. 170 (partim). Remarks.—This variety differs from I. labiatus in the much greater length of the hinge-lne in proportion to the height of the shell, in the greater convexity of the anterior margin, the smaller convexity of the ventral margin, and the less oblique form of the shell. On account of the greater length of the hinge-line the curvature of the ribs and growth-lines is broader than in I. labiatus. This variety appears to be confined to the zone of Holaster planus, and is common in the neighbourhood of Swaffham, Norfolk. The larger specimens which I have seen are not sufficiently perfect for figuring, but a characteristic example is figured by Sowerby. T'ypes.—From the zone of Holaster planus of Swaffham. The smaller specimen figured by Sowerby is in the British Museum (Fig. 40), but the larger specimen cannot be found. Distribution.—Zone of Holaster planus of Purley Junction Station, Surrey, and Swaffham, Norfolk. Fias. Lae PLATE XLV. Genus—InocErAMts, Sowerby. I. neocomiensis, VOrb. 1, Hythe Beds, Lympne. Museum of Practical Geology, No. 21133. Left valve. 2, Lower Greensand, Atherfield. Sedewick Museum, Cambridge. Right valve. .(P. 262. T., Salomom, VOrb. Maiminillatus bed, Copt Point, Folkestone. Sedgwick Museum. Internal casts of left valves. 406, dorsal view of 4a. (P. 263.) I. anglicus, Woods. (P. 264.) 8. Red Limestone, Hunstanton. Sedgwick Museum. a, part of right valve; b, dorsal view, 9. Gault, Folkestone. Sedgwick Museum. Left valve. 10. Gault, Folkestone. British Museum, No. L9665. Right valve. I. concentricus, Park. Gault, Folkestone. British Museum, No. L5002. Left valve. (P. 265. PALZONTOGRAPHICAL SOCIETY, 1910 Vol.ll PLATE XLV = BANS ERACE OU eq Te) DAMES Stn Glia London Stereoscopic Co. Imp. te Fias. PLATH XLVI. Inoceramus (continued). 1—10. I. concentricus, Park. 1—7, Gault, Folkestone. 8—10, Upper Green- sand, Blackdown. (P. 265.) cow o Pw De 10. . British Museum, No. L5002. Right valve and umbo of left valve. . Sedgwick Museum, Cambridge. Right valve and umbo of left valve. Sedgwick Museum. a, left valve; b, dorsal view of the same. . Sedgwick Museum. a, left valve; b, anterior view of both valves. . Sedgwick Museum. a, left valve, b, dorsal view of both valves. . Sedgwick Museum. Right valve. . Sedgewick Museum. Left valve. . Museum of Practical Geology, No. 21183. a, right valve; b, dorsal view of the same. . Sedgwick Museum. a, right valve and umbo of left valve; 6, dorsal view of both valves. Bristol Museum. a, right valve and part of displaced left valve ; b, anterior view of both valves. PALZONTOGRAPHICAL SOCIETY, 1910 Volll PLATE XLVI CRETACEOUS EAVMELLIBRANC HIE T.A.Brock, del ce ers London Stereoscopic Co. lmp PLATE XLVII. Inocerames (continued.) Fias. 1,2. JI. concentricus, Park. 1, Upper Greensand, Blackdown. Bristol Museum. Left valve. 2, Red Limestone, Hunstanton. Sedgwick Museum, Cambridge. Left valve. (P. 265.) 3—14. TI. concentricus var. subsuleatus, Wiltsh. Gault, Folkestone. Left valves. (P. 268.) 3, 4. Sedgwick Museum, Cambridge. 5. Museum of Practical Geology, No. 21154. 6. British Museum, No. 5003. 7—9. Sedgwick Museum. 10. British Museum, No. L9664.. 11—13. Sedgwick Museum. 14. Museum of Practical Geology, No. 21153. 15—20. JI. sulcatus, Park. Gault, Folkestone. 15, British Museum, No. L11797; a, left valve; b, right valve; c, dorsal view. 16—20, Sedgwick Museum. 16, 18—20, left valves; 17, anterior view. (PE2695) PALZONTOGRAPHICAL SOCIETY, 1910 Vol.ll PLATE CRETACEOUS LAM! Be La RAN CEivAs: XLV11 : = pic Co. Imp. i PAE SV Inoceramus (continued). Figs. Red Limestone, near Louth. Sedgwick Museum, 1. I. tenuis, Mant. Cambridge. a, left valve; b, dorsal view. (P. 271.) I. Crippsi, Mant. Upper Greensand (zone of Pecten aspev), Warminster. aS (P. 273.) 2. Museum of Practical Geology, No. 18898. a, right valve; b, dorsal view. 3. High variety. Sedgwick Museum. Right valve. 4,5. I. Orippsi var. reachensis, Eth. Lower Chalk (zone of Holaster 4, British Museum, No. subglobosus), Blue Bell Hill, Burham. L10386. Left valve. 5, Mr. Dibley’s Collection. (P. 278.) Right valve. PALA ONTOGRAPHICAL SOCIETY, 1910 Volll PLATE. XLVI Ley) ao - - CRETACEOUS. TAdvis Ie iniEiReAINi@ ear T.A.Brock, del. London Stereoscopic Co. Imp. Fias. bo OsnOe PLATE XLIX. Inoceramus (continued). I. Crippsi vay. reachensis, Eth. Lower Chalk (zone of Holaster subglobosus), Blue Bell Hill, Burham. British Museum, No. L10387. Right valve.> ¢P: 278.) I, Kiheridget, Woods. Lower Chalk. Sedgwick Museum, Cambridge. (P. 278.) 2. Chalk Marl, Hunstanton. a, left valve; b, hinge of the same. 3, 4. Totternhoe Stone (zone of Holaster subglobosus), Burwell. 3, one of the types; a, left valve; b, dorsal view of the same. 4, Right valve. I, pictus, Sow. Lower Chalk. (P. 279.) 5. Zone of Holaster subglobosus, Burham. British Museum, No. 44683. Right valve. 6. Locality unknown. British Museum, No. L22259. Left valve. PALZONTOGRAPHICAL SOCIETY, 1910 Vol.ll PLATE XLIX f Le a \ ie #2 ak ‘ ’ \ CRETACEOUS] CA Vin sis ANG eine T.A. Brock, del. London Stereoscopic Co. Imp. PLATE i. TnNoceraMus (continued). Fias. 1—6. I. labiatus (Schloth.). Middle Chalk. (P. 281.) 1. Locality unknown. British Museum, No. L20948. Left valve. 2,3. Eastbourne. Sedgwick Museum. 2, Left valve. 38, Right valve. 4. Zone of Rhynchonella Cuvieri, Blane Nez, Pas de Calais. Sedgwick Museum. Hinge and anterior margin of right valve. 5. Plumpton. British Museum, No. 5861. The specimen figured by Mantell, Foss. 8S. Downs, pl. xxvu, fig. 3, p. 216. Right valve. 6. Middle Chalk, near Warminster. Dr. Blackmore's Collection. Right valve. PALZONTOGRAPHICAL SOCIETY, 1910 PILZ TB. IU: Vol. V LAMELLIBRANCHIA. a SS wD) REACH OW C Co. Imp. London Stereoscopic "A Brock, del. PALAONTOGRAPHICAL SOCIETY. INSTITUTED MDCCCXLVIT. VOLUME FOR 1910. LONDON: MDCCCCXI. Ye ' A MONOGRAPH OF THE TERRESTRIAL CARBONIFEROUS ARACHNIDA Gel bea ISAT ATEN: BY REGINALD INNES POCOCK, F.L:S., SUPERINTENDENT OF THE ZOOLOGICAL SOCIETY'S GARDENS, REGENT’S PARK, LONDON. OND OUN: PRINTED FOR THE PALMHONTOGRAPHICAL SOCIETY. JANUARY, 1911. . a aed = v SYSTEMATIC Order SCORPIONES Eobuthus -- holti Palzomachus — anglicus Archeoctonus = elaber -—— tuberculatus Cyclophthalmus — euglyptus Anthracoscorpio a sparthensis dunlopi ... = buthiformis Order PEDIPALPI... Suborder Uropyet Geralinura ... zi britannica Suborder AMBLYPYGI ... Greophonus — anglicus Order ARANEA Suborder MrsoruE.a ... Eocteniza ... ine silvicola... Arthrolycosa Suborder OpistTHoTHEL® Archeometa nephilina Order RICINULEL ... Curculioides — ansticil Poliochera .. ~- alticeps INDEX. Order HAPTOPODA Plesiosiro ... eae madeleyi Order PHALANGIOTARBI Phalangiotarbus = subovalis Geraphrynus angulatus hindi tuberculatus - eggintoni torpedo = angustus Order ANTHRACOMARTI Brachypyge -- carbonis Maiocercus... e — celticus Anthracomartus hindi — priesti Anthracosiro woodwardi _.. — fritschi Trigonotarbus — johnsoni Eophryuus ... a — prestvici Kreischeria verrucosa Aphantomartus == areolatus... ? Order OPILIONES or ANTHRACO- MARTI Nemastomoides — elaveris PAGE 49 SSI SS See Sy do) (0) Si Ny ee) — 00 OO OO a WwW bd A MONOGRAPH OF THE TERRESTRIAL CARBONIFEROUS ARACHNIDA OF GREAT BRITAIN, tf INTRODUC LION. Most of the material upon which this monograph is based came from Coseley, near Dudley, and was kindly lent to me by the following gentlemen, to whom my grateful thanks are due: Dr. Wheelton Hind, Mr. S. Priest, Mr. Henry Johnson, the late Mr. William Madeley, and Mr. Walter Egginton. I am also ereatly indebted to the Director of the Geological Survey and to Dr. Kitchin for the loan of specimens from the Survey Museum in Jermyn Street; to Dr. Smith Woodward, the Keeper, and to Dr. F. A. Bather, the Assistant-Keeper, of the Geological Department of the British Museum, not only for the loan of specimens, but also for the privilege of free access to the collection of fossil Arachnida in that institution; to Dr. Henry Woodward for the opportunity to examine and describe examples that had been entrusted to him by Dr. Moysey, Mr. W. A. Parker, and Mr. F. Holt; and to Mr. Robert Dunlop for two very interesting specimens from Scotland. Without the help thus generously afforded, the present work could not have been attempted. Finally, I wish to thank Miss Gertrude M. Woodward for the care she has taken in the execution of the plates and text-figures illustrating this monograph. The species forming the subject-matter of the following pages are referred to seven orders: Scorpiones, Pedipalpi, Aranez, Ricinulei, Haptopoda, Phalangio- tarbi, and Anthracomarti, one species doubtfully belonging to the Opiliones. The Haptopoda, Phalangiotarbi, and Anthracomarti are, so far as is known, wholly extinct. I am unable to offer any satisfactory suggestion as to the cause of their extinction, there being nothing in their organisation very obviously calculated to make them less fitted for survival than the Ricinulei. The reason for the survival of Scorpiones and Pedipalpi is perhaps to be found partly in their possession of 1 bo TERRESTRIAL CARBONIFEROUS ARACHNIDA. powerful chelate palpi. But in addition to these efficient prehensile organs the Scorpiones have a poisonous sting; the Uropygous Pedipalpi have protective acid- elands at the tip of the opisthosoma, while the Amblypygi are extraordinarily quick in their movements and have a highly specialised tactile organ in the legs of the first pair. The Aranez have probably survived in virtue of their snare- and cocoon-making spinning glands, coupled with poison-glands in the mandibles; and there is some evidence that existing Opiliones are protected by their scent-glands. Since there is no reason to suppose that the members of the extinct orders above enumerated had specialised glands either for offensive or defensive purposes, and since their palpi were short and non-prehensile, and their organisation suggests that they were comparatively slow-moving, cryptozoie forms, it might be supposed that these attributes supply the needed explanation, were it not that the Ricinulei re- semble them in most of these particulars. One thing, however, must not be for- gotten. An important factor in the evolution of terrestrial Arachnida has been, in my opinion, a change from the method of pairing, as practised by Scorpions, to new and special methods, resulting in the modification of a part of one of the prothoracic limbs into an intromittent organ, often of great complexity. This may be seen in the Aranez, where the palpi are modified, in the Solifuge, where the mandibles are modified, in some of the Acari, and lastly in the Ricinulei, where the legs of the third pair are modified. Even the Opiliones possess very special secondary repro- ductive organs. There is no evidence, nor any reason to suppose, that the Haptopoda, Phalangiotarhi, or Anthracomarti had departed from the normal in their breeding habits; and it is quite conceivable that the Ricinulei have outlasted their Carboniferous contemporaries belonging to those three orders on account of their very specialised methods of copulation. Up to the present time the only orders of Arachnida known to be represented in British Carboniferous strata, belong to the Scorpiones, the Phalangiotarbi, and the Anthracomarti. Of Scorpiones several species have been described, mostly by Dr. Peach from Scotland; one species of Phalangiotarbi was named many years ago by Dr. Woodward; while of Anthracomarti some five species have been made known by Dr. Woodward and myself. As an historical fact it 1s interesting to record that im 1826 Dean Buckland described two Arachnida as Coleopterous insects. One of these was detected to be an Arachnid by Dr. Woodward, and the other I have now been able to identify as also belonging to that class. The material at my disposal has shown that the British Carboniferous fauna is at least as rich in species and genera of Arachnida as that of Continental Kurope and North America, the species of which have been described for the most part respectively by Kusta and Fritsch and by Scudder. Fritsch can hardly be acquitted of the charge of needlessly creating species and genera. Scudder’s work on the contrary is open to no such accusation. It appears to me that in the present state of our knowledge of this group, species in themselves are of very little importance. REVISION OF PREVIOUSLY PROPOSED CLASSIFICATIONS. 3 Whenever possible, therefore, | have avoided making them. The characters of the orders, families, and often of the genera are, on the contrary, of the highest interest. They show that the Pedipalpi, Araneze and Ricinulei, and some of the Scorpiones have existed almost unchanged down to the present day ; and that other Scorpions, on the other hand, e.g. Mobuthus, differed considerably from modern types in one feature at least, which may be described as Merostomatous. Apart from this one fact, and for a possibly closer connection between the spider named Arthrolycosa and the Amblypygous Pedipalpi than exists in modern types, these orders were as sharply defined as they are now; and unless, as is possible, the extinct orders, Haptopoda, Anthracomarti and Phalangiotarbi, serve to bridge to a certain extent the interval between the Opiliones and more primitive orders of Arachnida, it can hardly be claimed that the Carboniferous fauna throws much, if any, ight upon the origin and mutual relationship of existing orders of the class. In other words, the available paleontological data supplied by a study of these Carboniferous Arachnida do not furnish any strong evidence in favour of the evolution of the class. Hence, for the common stock whence the Epectinate Arachnida originated, we must look to deposits much earlier than those laid down in the Carboniferous epoch. PAN NOTATE DP REVISION OF PREVIOUSLY PROPOSED CLASSIFICATIONS OF CARBONIFEROUS ARACHNIDA. 1. Karscu, F. E., Zeitschr. deutsch. geol. Ges., 1882, pp. 556—5d61. Order 1. ARANEAI, Family Lipuistip”. Genus Protolycosa, Roemer: P. anthracophila, Roemer. Order 2. OPILIONES. Family TroeuLips. Genus Kreischeria, Geinitz: K. wiedei, Geinitz. Order 3. ANTHRACOMARTI. Family ARCHITARBID. Genus Architarbus, Scudder: A. rotwndatus, Scudder ; subovalis, Wood- ward ; silesiacus, Roemer. Genus Anthracomartus, nov.: Ss ce es , 1@ Pe humerus Sale ) brachium : . 20; width of brachium . 5 g3 back of the hand » 9s » Or Ineindl 6 se movable digit. : 20 In the above-given table the probable total length of the tail has been guessed from the length of the fourth segment, 20 mm. being allowed for the fifth segment and the vesicle, which are not preserved. These two missing seements were probably not less, and may have been more than the amount supposed, since the fifth caudal segment is never shorter and is usually longer than the fourth in living Scorpions. The type and only known specimen of this species is contained on the two pieces of a split shale from the Upper Coal Measures of Drumgray, near Airdrie, in Scotland. It is in the possession of Mr. R. Dunlop, to whom I have dedicated 24. TERRESTRIAL CARBONIFEROUS ARACHNIDA. the species in acknowledgment of his kindness in sending it to me for description. The type of this species approaches twice the length of the type specimen of A. sparthensis. \t also differs in its proportions, the tail being longer and the manus of the chelanarrower. In A. sparthensis, for stance, the first four seements of the tail only exceed twice the length of the carapace by about one-third of its length, the carapace being approximately as long as the first and second segments together, whereas in A. dunlopi the first four caudal segments exceed twice the length of the carapace by at least half its length, and the carapace is distinctly shorter than the first two caudal segments so far as can be judged. In A. sparthensis, again, the width of the manus is nearly half the length of the movable digit, while in A. duntopt it is rather less than one-third of the length. The smaller size of the example of A. sparthensis, coupled with the shorter tail, might be attributed to immaturity, were it not that the two known examples of this species are approxi- mately equal in size and have all the appearances, judging from the firmness of the exoskeleton, of being adult. Moreover, the hands of the chele in young Scorpions are relatively narrower than in full-grown examples. Hence their ereater relative width in A. sparthensis as compared with A. dunlopi is quite irreconcilable with the conclusion that the former specific name has been assigned to young examples of the latter species. For these reasons I have not hesitated to describe Mr. Dunlop’s specimen as an example of a distinct species. This specimen was for some time in the possession of Dr. Peach, who made a drawing of it in close agreement with my own restoration. This drawing, accompanied by a short account, was published by Mr. Dunlop in the Annals of the Glenfield Rambler, No. 2, pp. 60—64, 1898, but no name appears to have been assigned to the specimen. + Plate sil, fie; Is) Mext= ’ Anthracoscorpio buthiformis, sp. nov. Plate I, fig. 2 figures 6—8. Dorsal integument finely and closely granular; neither the carapace nor the first six terga of the opisthosoma visibly keeled. Carapace about as long as its posterior width, its length a little exceeding that of the first and second caudal segments together, and about equal to that of the second and third, and to the fifth and half the fourth. The ocular tubercle in the middle of its anterior half; a shallow median longitudinal groove running from it posteriorly and expanding and deepening just before the posterior border ; the anterior border of the carapace apparently slightly convex, perhaps with a small median excrescence ; the posterior border slightly convex in the middle. erga of the abdominal portion of the opisthosoma showing the anterior elevated rim, this region, thus distended, a little more than twice the length of the carapace. Tail, when complete, no ANTHRACOSCORPIO. 25 doubt a little more than three times the length of the carapace, for without the post-anal spine it is about twice and a half times the length; segments one to five gradually increasing in length ; the first segment the widest, much wider than long, the second and third also wider than long, the fourth about as long as wide, the fifth longer than wide; the upper surface of the segments normally and strongly keeled, the superior keels converging on segments one to four, almost parallel on segment five; the upper surface hollowed between the superior keels, which, like the superior lateral keels, are granular. Chelze slender, humerus and brachium each much shorter than the carapace, which is slightly shorter than Fic. 6.—Anthracoscorpio buthiformis, sp. n.; four times nat. size.-—Coal Measures; Sparth, near Rochdale. W. A. Parker Collection. the manus with its digits. Manus slender, apparently keeled above and slightly wider than the brachium. Measurements i min.—Total length, exclusive of post-anal spine and chelicere, 21; length of carapace 3°5, of abdominal portion of opisthosoma 8; of caudal seginents one to five about 10; length of first caudal segment 1°35, of second 1:6, of fourth 25 of ith (2:55 width of first 2:5, of second 2 +, of fitth 2—; length of manus and digits about 4. Coal Measures of Sparth, near Rochdale. Type above described in the Collection of Mr. W. A. Parker (Pl. II, fig. 1). I have selected this specimen as the type because it shows the structure of the dorsal surface very clearly. Only fragments of the legs are preserved, but the details of the chele of the left side can be deciphered. 4. 26 TERRESTRIAL CARBONIFEROUS ARACHNIDA. In addition to this specimen I have seen several examples from Dudley, which, in the absence of satisfactory proof of their distinctness from each other and from the type, I provisionally refer to this species. With the exception of one small specimen, which is immature if conspecific with the rest, I judge these specimens to be mature from the apparent thickness of the exoskeleton. The species therefore differs from A. sparthensis by its much smaller size. In the type specimen also the tail is shorter, the carapace being half the length of the first four caudal segments, whereas in A. sparthensis, as testified by the type, the varapace is less than half that length. I subjoin the following notes on the examples from the Dudley Coalfield : (1) Specimen in Mr. Madeley’s Collection showing the chele, the trochanters, femora, and part of the patellz of the leg of the first, second, and third pairs, the Lon Fie. 7.—Anthracoscorpio buthiformis, sp. n.; about Fic. 8.—Anthracoscorpio buthiformis, sp. n.; three three times nat. size.-—Coal Measures; Coseley, times nat. size.—Coal Measures; Coseley, near near Dudley. W. Madeley Collection. Dudley. Wheelton Hind Collection. greater part of the carapace, of which only the anterior portion is missing, and, following the carapace, a thin strip representing the first tergal plate of the opisthosoma. Behind the latter there he, displaced to one side, the fourth, fifth, sixth, and seventh terga of the opisthosoma, which resemble in a general way the corresponding plates of Dr. Hind’s specimen (No. 2). The carapace exhibits traces of the median ocular tubercle in front of its middle, but some distance from its anterior edge. ‘The chelz are slender, and recall those of some existing members of the Buthide, the “manus” being narrow, although wider than the brachium ; the digits are long and slender, and apparently in contact throughout their length, the movable digit being a little more than twice the length of the back of the hand. Approximate measurements in mm.—Width of carapace 3°5, of opisthosoma 4; length of humerus + brachium of chela 6, of manus + digits 5. (2) Specimen in Dr. Wheelton Hind’s Collection, showing the dorsal surface of the posterior part of the carapace, seven tergal plates and the first and second ANTHRACOSCORPIO. 27 caudal segments of the opisthosoma; also fragments of some of the anterior legs and apparently the maxillary processes of those of the first pair, where the anterior part of the carapace is missing. Of the fourth leg the trochanter, femur, patella, and part of the tibia are well exhibited. No trace of eyes is discernible. The sculpturing of the carapace, terga, and caudal segments is obscured, but the terga of the opisthosoma show clearly the anterior smooth elevated area which is normally overlapped in living Scorpions by the posterior border of the plate in front. Approximate measurements in mm.—Leneth of abdominal terga of the opistho- soma 9°5, first tereum 1, third 1:5, fifth 2; width of opisthosoma 5; length of first and second caudal segments 4; femur of fourth leg 4, patella 5. (3) Specimen in Mr. Egginton’s Collection, showing, so far as the trunk is concerned, nearly the same features as Dr. Hind’s example, the abdominal terga and two caudal segments of the opisthosoma being preserved. The anterior portion of the carapace is too much obliterated for description, but the ocular tubercle, in advance of the middle of this plate, is well shown with its two eyes. Fragments of appendages are shown on each side of the anterior half of the body, the femur of the left chela with an anterior granular crest, such as is present in most recent Scorpions, being preserved. Approwimate measurements in miu.—Total length from anterior end of carapace to posterior end of abdominal portion of opisthosoma 12, the carapace about 3 5, the rest 8°5; width of opisthosoma 5; distance of eyes from posterior edge of carapace 2; length of first caudal segment about 1, width nearly 2. (4) Specimen in Mr. Egginton’s Collection without tail and with the rest of the opisthosoma curved upwards as in the act of stinging. The chief interest of this specimen lies in the fact that the chelicerz are preserved, showing obscurely the normal forcipate character of these appendages. Fragments of the appen- dages are obscurely indicated. Length of carapace about 3 mm. (5) A very small, probably young specimen in Mr. Hgginton’s Collection, showing the dorsal view of carapace, of the anterior seven terga of the opisthosoma, and of the base of the tail. Total length (excluding base of tail) about 5 mm. ; length of seven segments of opisthosoma 3°5 mm.; width 2 mm. (6) Specimen in the British Museum, No. I. 1555 (Pl. I, fig. 2), from Coseley (Henry Johnson Collection). This example is of peculiar interest, since it shows portions of the sternal surface of the prosoma. The sternum is pentagonal, with its posterior border somewhat deeply excised; a little behind the excision lies a subtriangular genital operculum, and behind this there is a small sclerite repre- senting the sternal plate of the pectines. Against the sides of the sternum on one side abut the coxe of the legs of the third and fourth pairs as in existing Scorpions; and in front of it may be traced faint indications of the coxe, with their maxillary processes, of the first and second pairs of legs; the maxillary 28 TERRESTRIAL CARBONIFEROUS ARACHNIDA. processes of those of the second pair appear to be exceptionally narrow. Seven terga of the opisthosoma are shown. These are very broad as compared with their length; but this may be due to flattening. At all events I do not propose to attach systematic weight to the character and separate this specimen specifically or generically from the others here described on the strength of this difference on the evidence of one specimen. Length of trunk (without tail) about 14 mm.; of seven segments of opisthosoma 9°5 mm.; width of opisthosoma about 6 mm. The following fossils of doubtful generic position have also been referred to the Scorpiones. (1) Segment of a tail from the Coal Measures of Carluke, Scotland (H. Wood- ward, Quart. Journ. Geol. Soc., vol. xxxu, pl. vi, fig. 5). (2) Portion of a carapace referred by Peach to Hoscorpius sp. (Trans. Roy. Soe. Edinb., vol. xxx, pp. 404—405, pl. xxu, figs. 11 to lla, 1883). The upper side of the carapace is swollen laterally, the swollen portions being separated by a median longitudinal groove, and each divided by lateral grooves into three portions. In front of the median groove hes the median ocular tubercle; lateral eyes are also described. According to Peach this carapace is intermediate between that of the species he described as Hoscorpius tuberculatus and 2. inflatus. (3) A carapace described by Peach as belonging to a species named Hoscorpius inflatus (Trans. Roy. Soc. Edinb., vol. xxx, pp. 405—406, pl. xxii, figs. 12 to 12d, 1883). It is described as having the greater portion of its surface puffed up into three pairs of lobules separated by deep sulci, which emanate from a deep median longitudinal sulcus. Peach himself suggests the possibility of this species belonging to the unclassified genus Cyclus. 'To a certain extent this author’s descriptions of LH. inflatus recall the characters of the carapace of some genera of Anthracomarti, such as Hophrynus and Kreischeria. Order PHDIPALPI, Latreille. Suborder UROPYGI. fenus GERALINURA, Scudder. 1884. Geralinura, 8S. H. Scudder, Proc. Amer. Acad. Arts Sci., vol. xx, p. 19. 1890. Geralinura, 8. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 454. 1904. Prothelyphonus, A. Fritsch, Paleoz. Arachn., p. 57. Fritsch established the genus Prothelyphonus upon the species described by Kusta as Thelyphonus bohemicus and later as Geralinwra bohemica. The alleged difference GERALINURA. 29 between Prothelyphonus and Geralinura is the segmentation of the carapace in the latter and its entirety in the former; but since I cannot find any evidence from Scudder’s figures of the type of Geralinura, namely G. carbonaria, that the carapace is segmented, I have placed Prothelyphonus as a synonym of Geralinura, reserving this name for the Carboniferous species of the Thelyphonide, not because they exhibit characters distinguishing them with certainty from existing genera, but because it is impossible to be sure that they belong to one or to more than one existing genus, and because the probabilities are in favour of their distinctness from all modern types. No species of this group has hitherto been recorded from Great Britain. Several specimens, however, are contained in the collections at my disposal, although the material is, in my opinion, neither sufficiently abundant nor well preserved to admit of specific differences being with certainty established between the specimens. Provisionally, therefore, I refer them to one species. The real interest of the specimens hes in the evidence they afford of the former existence of these Pedipalpi in Great Britain, and of their close agreement in structural characters with recent representatives of the suborder. Some of the Carboniferous specimens, that is to say, the two figured in this Monograph, seem to differ from modern types in haying the three last segments of the opisthosoma less sharply marked off from the ninth segment and both wider and longer. But it is impossible to affirm this character of all extinct forms. Geralinura britannica, sp. nov. Plate I, fig. 3; Plate II, fig. 3; Text-figure 9. A species of small size with the dorsal surface covered with coriaceous granula- tion. Chel rather short and small, the five distal segments together rather shorter than the carapace. The three terminal segments of the opisthosoma long, nearly half the length of the rest of thisregion. Segments of the caudal flagellum about as wide as lone. Measurements iv mm.—Total length from anterior end of carapace to end of the last segment about 17; length of carapace about 5, width 3°5; total length of opisthosoma (excluding flagellum) 11°5 ; width 4°5 ; length of segments two to nine, 8, ten to twelve (caudal portion) 3°5; length of visible portion of chela from base of femur 4:5. Coseley, near Dudley. Type in Mr. Walter Egginton’s Collection, No. 51 (Pl. I, fig. 3). This collection contains a second and less well-preserved specimen (No. 49) showing no features justifying its specific distinction from the type; and in Mr. Madeley’s Collection there is an example from Coseley exhibiting the underside structurally in agreement, so far as can be seen, with recent forms. Its total 30 TERRESTRIAL CARBONIFEROUS ARACHNIDA. length is about 15°5 mm., the opisthosoma being 9°5 mm. and the prosoma 6 mm., the width of both regions being about 5 mm. There is a distinct spinform process at the anterior extremity of the carapace as in certain recent forms, e. g. Labochirus. In Dr. Moysey’s Collection there is a specimen from the Shipley Claypit with the dorsal side exposed (PI. I, fig. 5). The anterior portion of the carapace is broken away, showing vaguely the coalesced coxee of the chele and the distal portion of the right chela. Behind the posterior border of the carapace there is a triangular plate which I regard as the posterior sternal plate of the prosoma, the exposure of which suggests that the overlying dorsal area was membranous ; on each side of it may be seen the coxe of the legs of the last pair. Nine terga of the opisthosoma are clearly discernible, but the three terminal segments of this Fia. 9.—Geralinura britannica, sp. n.; restoration of ventral surface, three times nat. size.—Coal Measures ; Coseley, near Dudley. W. Madeley Collection. region are vaguely defined; they appear, however, to be comparatively large both in length and width; the post-anal flagellum is not preserved. Both the carapace and the terga and lateral membrane of the opisthosoma are granularly coriaceous. Measurements in am.—Total length about 20; length of opisthosoma 13, its leneth, excluding the last three segments, 10, its width 6; length of chela, excluding coxa, 7. This specimen is a little larger than the type and has the chelee decidedly longer. The difference in length, however, both of the body and the chela, may be attribut- able to age; and since the males of recent species very commonly have the chele much longer than they are in the females, it would be rash to attach specific importance to the difference observed, even if the type specimen were known to be fully adult. GRAOPHONUS. 31 Suborder AMBLYPYGI. Genus GRAEOPHONUS, Scudder. 1890. Greophonus, 8S. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 453. Although Scudder referred this genus to the same family of Pedipalpi as Geralinura, the two genera obviously belong respectively to the two suborders of the Pedipalpi known as Amblypygi and Uropygi. Scudder only admitted one species of Greophonus, which he named G. carbonarius ; but it appears to me to be very doubtful if the two specimens passing under that name can be referred even to the same genus. The type of carbonarins is an abdomen from Cape Breton and now in the Museum of the McGill College, Montreal. It was described as Libellula carbonaria under the belief that it belonged to a Neuropterous insect. It consists of twelve segments ; but these are unlike the segments of any known Amblypygous Pedipalp, especially in the large size of the first and second plates. Moreover, the segments from the second to the seventh inclusive, are marked on each side near the margin by a circular impression. In the Amblypygi the tergal impressions are remote from the margin. On the other hand, the specimen from Mazon Creek, Illinois, upon which the genus Greophonus was quite clearly based, appears undoubtedly to be a Pedipalp of the suborder Amblypygi. Although Scudder identified this as G. carbonarins, it cannot, on the evidence, bear that specific name, as a comparison between the figures of this specimen (fig. 3, pl. xl, of the above-cited monograph) and the figures of Libellula carbonaria (pl. xl, figs. 2. 6) will make evident. In the Mazon Creek specimen the muscular tergal impressions are in agreement with those of a Phrynus; agreement may also be traced in many other particulars, such as the form of the carapace and the position of the ocular tubercle and the muscular grooves and pits. Scudder was, of course, mistaken in describing one of the chelee as complete and nipper-like, its distal segments being obviously missing. It is in the structure of these appen- dages that Greophonus differs principally from recent genera of the group. Not only are they comparatively short and stout, especially with respect to the femoral segment, but, in addition, the axial rotation, which enables these limbs to fold up in a horizontal plane in recent forms, appears to be much less marked. They are, in fact, more porrect and fold in a nearly vertical plane, as was no doubt the case in primitive members of the Pedipalpi when the chele or palpi presented greater resemblance to the ambulatory limbs than is found in recent forms. This appears to me to be the chief character of morphological interest to be detected in Greophonus. One other distinctive feature may be mentioned. In all the speci- mens referred to this genus, where the carapace is well preserved, its anterior area, bearing the median ocular tubercle, is narrow and produced. This is shown o2 TERRESTRIAL CARBONIFEROUS ARACHNIDA. not only in the examples that I have seen, but also in Seudder’s example from Mazon Creek, which I propose to call Grxophonus scuddert. Scudder describes this specimen as punctured. I do not doubt, however, that it was in reality finely granular. It is somewhat singular that although only one undoubted specimen of Grxophonus has been discovered in North America, and none have been recorded from Bohemia, the genus is represented in Britain by many specimens in the Carboniferous Beds of Staffordshire and South Wales. Greophonus anglicus, sp. nov. Plate I, fig. 4. Carapace approximately as long as wide, cordate, narrowed and produced anteriorly ; the median ocular tubercle rounded, placed near the centre of the narrowed anterior portion, and defined behind by a crescentic groove; the area behind the tubercle rather flat; the median portion of the posterior part of the carapace a little elevated and marked with three impressions or muscular pits, one median in front and a pair, smaller and shallower, behind; from points on each side near these impressions radiate three grooves towards the margin. Opisthosoma elliptical, longer than wide, the terga marked with the normal muscular impres- sions. ‘lhe distal end of the femur of the fourth leg, in its natural position, extending back beyond the extremity of the opisthosoma. Tibia of palp or chela short, a little more than twice as long as wide, its length a little exceeding half the length or width of the carapace; its inner edge apparently armed with two spines; tarsus of chela apparently not less than half the length of the tibia, and also armed internally with two spines. Approvimate measurements in mm.—Total length 20; median length of carapace 7'0, lateral length 8:5; greatest width 8°5, width across front on a level with the ocular tubercle 2°5; length of opisthosoma 11?; length of segments four to nine 75; width of opisthosoma 8°5; length of tibia of chela 4, width 2. Coseley, near Dudley. The type, above described, is in the Collection of Mr. Walter Egginton (No. 1). In addition to the type Mr. Egginton’s Collection contains several examples of Greophonus, which I provisionally refer to this species. All are from Coseley. The following points in them may be noted : No. 40. Carapace approximately as in the type, the anterior oculiferous projection clearly shown. ‘The terga of the opisthosoma are granular, and have a row of coarse granules along the posterior border. This region is narrower as compared with its length than in the type, the difference being perhaps sexual. Total length 14 mm., length of carapace 6, width 6°5; length of opisthosoma 8 ; femur of fourth leg about 8. Figured in PI. I, fig. 4. No. 2 shows more of the appendages than are seen in the type and No. 40, but HOCTENIZA. 33 the anterior portion of the carapace is concealed ; there is no evidence therefore that it projected forwards as im the other specimen. The greater portion of the chela is preserved, and the chelicere project forwards between their bases as a pair of slender rods. The cox of the posterior three pairs of legs are to be seen radiating from the narrow sternal area, and the legs of the second and third pairs are preserved nearly down to the ends of the tibie. The femur of the fourth leg is noticeably shorter than in No. 40. This difference may possibly be a question of age, the specimen now described being smaller than No. 40. In the chela the femoral segment appears to be spined internally. Approwimate measurements in mm.: Total length 11; median length of carapace 3:5, width 4; length of opisthosoma 6°5, width 5; length of femur of second leg 4, of third 5, of fourth 5°53; coxa and trochanter of chela 2, femur 2, tibia 2°5. No. 20: Larger than No. 2, but showing almost exactly the same features ; the femur and tibia of the chela armed internally with a pair of spines. Approximate measurements in min.: Total length 15:5; length of carapace 5, width about 6 ; length of opisthosoma 9, width 6°5; length of femur of second leg 7, of third 7°5, of fourth 9; length of femur of chela 3, its width 1°8; length of tibia of chela 4, its width 1°8. In Mr. Henry Johnson’s Collection from Coseley there is a specimen less well preserved than those described above and showing no points worthy of special comment. Its total length is about 15°5 mm., of which the carapace is 5 mm. and the opisthosoma 8°5 mm.; femur of third leg 6°5 mm. In the Museum of the Geological Survey, Jermyn Street, there are a well- preserved opisthosoma, measuring 15 mm. long and 8 mm. wide, and a carapace measuring 4°5 mm. long and 6 mm. wide, which perhaps belong to the same species. ‘They were found at the tip of an abandoned shaft (Glasbrook’s) close to Cadoxton village, one and one-eighth miles north-east of Neath Station in 8. Wales. There is no reason to suppose that these fragments belong to the same specimen. It may be noted that this carapace bears considerable resemblance to that of G. scuddeii, but has the produced anterior region larger. Order ARANHA, Sundevyall. Suborder MESOTHELA. Genus EOCTENIZA, nov. Generic Characters.—Carapace with its anterior portion somewhat sharply con- stricted to form a narrow, rounded, elevated, and convex cephalic area, defined from the large and broadly cordate posterior portion by a pair of shallow grooves, 5) 34 TERRESTRIAL CARBONIFEROUS ARACHNIDA. which nearly meet in the middle line. This cephalic area bears the eyes, arranged in a transversely elongated, suboblong cluster, near its anterior border. The posterior area of the carapace is marked with three pairs of radiating grooves, those of the first pair being short and of the other pairs long; behind the posterior pair of these there is an angular median depression, the central fovea, from which passes a posterior pair of grooves. Opisthosoma oval, showing six distinct tergal, plates. Type Species.—Nocteniza silvicola, sp. nov. In the Carboniferous genera and species of Aranez with segmented opistho- soma, namely Arthrolycosa antiqua, Harger, Scudderia carbouaria, Kusta, ? genus fortis, Fritsch, ? genus beecheri, Fritsch, Molycosa lorenzi, Kusta, Protolycosa anthra- cophila, Roemer, Geralycosa fritschi, Kusta, and Rakovnicia antiqua, Kusta, there appears to be no differentiated cephalic area such as is seen in Mocteniza. In Palaranea borassifolia, Fritsch, which its describer, in his last paper, re-named Arthrolycosa ? palaranea, there is no evidence that the opisthosoma is segmented, and therefore no reason for assigning the fossil to the genus Arthrolycosa. The type of Holycosa lorenzi shows only a side view of the animal; but in this genus it appears that the whole carapace is strongly elevated. It may be added that the species antiqua, carbonaria, fortis, beecheri, lorenzi, and borassifolia, which Fritsch refers to the one genus Arthrolycosa, represent at least six genera and possibly as many families if the drawings are to be trusted. Eocteniza silvicola, sp. nov. Plate IT, fig. 4. Carapace 5 mm. long, 4 mm. wide ; abdomen about 5 mm. long, 3°5 mm. wide. Coseley, near Dudley. Type and only known specimen in the Collection of Mr. Walter Kgginton. Genus ARTHROLYCOSA, Harger. 1874. Arthrolycosa, O. Harger, Amer. Journ. Sci. [3], vol. vii, p. 219. 1889. Arthrolycosa, C. FE. Beecher, Amer, Journ. Sci. [3], vol. xxxviii, p. 219. I refer with doubt to this genus a fossil (Text-fig. 10) in Dr. Wheelton Hind’s Collection, which is of very great morphological interest, although its exact syste- matic position is indeterminable. That it belongs to the order Aranez rather than to the Pedipalpi, I infer from the shape of the carapace and of the opisthosoma. The carapace, although imperfect, appears to be about as broad as long, with nearly straight anterior and posterior borders and evenly convex lateral borders. It is marked with radial impressions and a somewhat A-shaped median ARTHROLYCOSA. Bis) impression just in front of the posterior border. Faint imdications of the basal segments of the legs are traceable on one side, no trace of the coxe or sternal area of the prosoma being observable. he opisthosoma is wide, with its lateral and posterior borders strongly rounded ; it 1s markedly narrowed in front and is distinctly segmented on its dorsal area, the terga extending across the whole width of this region from side to side. Of the segmentation of the ereater part of the ventral surface I can affirm nothing with certainty except as regards the posterior extremity, where two annuliform segments surround the last or anal segment. The latter, as I interpret the fossil, consists of a transversely subelliptical tergal plate and of a crescentic sternal plate. Fic. 10.—? Arthrolycosa, sp—Coal Measures ; Coseley, near Dudley. Wheelton Hind Collection. a, dorsal surface of carapace and of opisthosoma, the posterior segments of the latter showing through the overlying last tergal plate visible on the dorsal side, about four times nat. size; 6, terminal segments of the opisthosoma, about six times nat. size. Approximate length and width of carapace 4+ mm.; length of opisthosoma 6 mm.; with 5°5 mm. or possibly less, if this region is expanded by crushing. Coseley, near Dudley. The morphological interest of this specinen les principally in the structure of the posterior segments of the opisthosoma, which are unlike those of all recent Aranex in being annuliform and firmly chitinised. In this character the fossil shows a nearer approach to the Pedipalpi, serving in a measure to bridge the interval between these two orders, which are admittedly related to one another. No trace of spinning appendages is to be seen. If they had been close to the anus, as in all recent Spiders except Liphistius, indication of this would probably have been preserved. Hence it may be supposed that they were situated somewhere near the middle of the ventral surface as in the last-named genus. 36 TERRESTRIAL CARBONIFEROUS ARACHNIDA. Suborder OPISTHOTHELA. Genus ARCHAOMETA, nov. Generic Characters.—Resembling in general form such recent genera as Nephila and Tetragnatha, and possibly, like these, belonging to the family Argyopidx. Cara- pace apparently cordate, narrowed in front. Legs very long and slender, probably 2,4, 3, 1 in order of length judging by the length of the femora, though possibly those of the first pair exceeded those of the third by reason of the probably greater length of their terminal segments. The legs of the first and second pairs in most recent Aranee (Spiders) are subequal in length, but in this Carboniferous genus those of the second pair greatly exceed those of the first. Femur of third longer than of first, femur of fourth a little longer than that of second. Abdomen long, apparently ‘ather longer than femur of fourth leg, but its exact length a little doubtful owing Fic. 11.—Archexometu nephilina, gen. et sp. n.; restoration of the ventral surface, showing the legs as far as the distal end of the femora and the probable form of the opisthosoma, about two and a half times nat. size.—Coal Measures; Coseley, near Dudley. W. Egginton Collection. to the want of definition of its posterior end; subcylindrical in shape, a little narrowed posteriorly, ovally convex apparently anteriorly and rather more than three times as long as wide. Type Species.—Archeometa nephilina, sp. nov. The discovery of this Spider is of very great interest, because it puts beyond reasonable doubt the existence in the Carboniferous epoch of the Arachnomorphe, which were previously not known to occur earlier than the Oligocene. It 1s, perhaps, necessary, however, to qualify this statement in connection with the genus and species described by Fritsch as Pyritaranea tubifera, which has the appearance of an Arachnomorphous form. But it is impossible to say much about this genus because the segmentation of the appendages, as represented by this author, is quite unlike that of any known Arachnid, living or extinct. Assuming that Pyritaranea was one of the Arachnomorphe, as Fritsch suggests by his refer- ence to the Clubionide in connection with it, Areheometa certainly differs from that genus in the greater length of its legs. In Pyritaranea, for example, an entire leg of the fourth pair only slightly exceeds the abdomen in length, and the CRYPTOSTEMMID 2. 37 other legs are correspondingly short. The palpi, on the contrary, which are not shown in the specimen of Archxometa, are of most unusual length. Archxometa nephilina, sp. nov. Text-figure 11. Total length about 10 mm. ; carapace about 8 mm. long, 2 mm. wide ; abdomen about 7 mm. long, 2 mm. wide; femur, trochanter, and part of coxa of first lee 4 mm., of second leg 7°5 mm., of third leg about 5 mm., of fourth leg 8 mm. Coseley, near Dudley. Type and only known specimen in the Collection of Mr. Walter Kgginton. Order RICINULEI, Thorell. Carapace or dorsal shield of the prosoma unsegmented, but with a movable plate, the cucullus, jointed to its anterior border and overhanging the jaws in front. Prosoma and opisthosoma united by a jointed waist, often marked by a lateral constriction. The opisthosoma either not visibly segmented or composed in the main of three very large segments, the last carrying a small jointed tail-like process, which is not always exposed; sometimes a shorter segment is visible in front of the first of the three large segments. It is needless to give a complete diagnosis of this order, derived from the existing genera Cryptostemma and Cryptocellus. For this, reference may be made to Hansen’s and Sorensen’s monograph of 1904. The characters briefly enumerated above are taken from the known Carboniferous genera, and are sufficient to dis- tinguish the Ricinulei from the other orders discussed in this Monograph. Family CryprostemMip®, Westwood. 1874. Cryptostemmidex, J. O. Westwood, Thes. Ent. Oxon., p. 210. 1884. Poliocheride, S. H. Scudder, Proc. Amer. Acad. Arts Sci., vol. xx, p» LG: 1890. Poliocheridx, 8S. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 444. 1892. Cryptostemmide, T. Thorell, Bih. Svensk. Vet.-Akad., vol. xvii, 4, No. 9, joe Se 1904. Cryptostemmatoide, H. J. Hansen and W. Sorensen, On Two Orders of Arachnida, p. 144. I provisionally refer the Carboniferous genera of this order to the family Cryptostemmide, which has the characters of the order. The two genera here admitted may be distinguished as follows : a. Opisthosoma elongate, narrowed posteriorly, not consisting mainly of three large segments ; cucullus transversely suboblong, markedly wider than long. Cureulioides. w. Opisthosoma shorter, widely rounded posteriorly, composed mainly of three large segments ; cucullus large, nearly as long as its basal width. —. . Poliochera. 38 TERRESTRIAL CARBONIFEROUS ARACHNIDA. Genus CURCULIOIDES, Buckland. 1837. Cureulioides, W. Buckland, Bridgewater Treatise (ed. 2), vol. ii, p. 76 (in part, C. anstici?). 1902. Curculioides, R. I. Pocock, Geol. Mag. [4], vol. ix, p. 439. 1890. Geratarbus, 8. H. Scudder, Mem. Bost. Soc, Nat. Hist., vol. iv, p. 447 (in part, G. seabrum). 1890. ? Kustarachne, 8. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 450. 1903. Kustarachne, A. L. Melander, Journ. Geol. (Chicago), vol. xi, p. 181. The genus Curculioides was based by Buckland on two fossils in ironstone nodules from Coalbrook Dale, which this author regarded and described as Coleopterous insects. One of these was named C. ansticit, the other C. prestvici. The latter was subsequently made the type of Hophrynus by Dr. Henry Woodward, who thus fixed C. ansticti as the type of Curculioides. In 1884 Scudder suggested that C. ansticii was an Arachnid related to Architarbus. I, on the cont ary, suggested that it was allied to Cryptostemina, judging solely from the figure of it published by Buckland. The correctness of this surmise and the reasons given in support of it have been confirmed by specimens in Mr. Egginton’s and Mr. Madeley’s Collections. That the Arachnid described by Scudder as Geratarbus scabrum is closely related to those that I refer to Curculioides is, 1 think, indisputable; but it is equally indisputable, in my opinion, that G. seabrum belongs to a different order of Arachnida from G. lacoei, which I have fixed as the type species of Geratarbus (Geol. Mag. [5], vol. vi, p. 511, 1910). About Kustarachne there is more room for doubt on account of Scudder’s statement that the opisthosoma consists of nine ce segments, including the short two-joited “ protuberant pygidium.” Although none of the specimens I have seen shows distinct signs of abdominal segments, the one in Mr. Madeley’s Collection possesses what might be called a “ protuberant pygidium,” and this process is also well exhibited in Buckland’s original figure. Nevertheless, it would have been difficult to justify the suggestion that Kustarachne, based upon Ky. tenuipes, belongs here, were it not that the species described by Melander as K. sulcata seems to be unmistakably akin to the examples in Mr. Kegeginton’s Collection, which show the ventral side. Melander described K. sulcata as deeply punctured and as being provided with a triangular sessile pygidium of two, possibly three, segments. Apart from this last character the abdomen seems to show no segments. It is possible, of course, that Kustarachne tenwipes and K. sulcata differ generically. Nevertheless, the measurements of the two type specimens agree suspiciously closely, and both came from Mazon Creek, Hhnois. I suspect that one shows the dorsal, and the other the ventral view of specimens belonging to the same species. ey) eo) CURCULIOIDES. » Curculioides ansticii, Buckland. Plate II, fig. 7; Text-figures 12, 15. 1837. Curenlioides ansticii, W. Buckland, Bridgewater Treatise (ed. 2), vol. ii, p. 76, pl. 46”, fig. 1. The exposed surface of both dorsal and ventral sides is closely covered with small punctures marking the hollows of granules. A specimen in Mr. Egginton’s Collection (Pl. I, fig. 7), showing the dorsal surface from the ventral side and the ventral surface from the dorsal side on the two halves of a split nodule, has the carapace flattish and only a little vaulted, and apparently about as wide as long, though its lateral margins are not clearly defined. The posterior end of the abdomen is markedly narrowed. Portions of the legs are well shown, especially on the right side. The first and third are preserved as far as the end of the patella, Fic. 12.—Cureulioides ansticii, Buckland; sugvested Fria, 13.—Curculioides ansticii, Buckland; dorsal sur- restoration of ventral surface of specimen No. 17, face, three times nat. size.—Coal Measures; Coseley, four times nat. size. —Coal Measures ; Coseley, near near Dudley. W. Madeley Collection. Dudley. W. Egginton Collection. of the second and fourth as far as the end of the femur. The first leo is the thinnest and the second the longest of the series, the femur of the second being about as long as the femur + patella of the third. Approvimate measurements mm mn.: Total length about 11, length (without cucullus) and width of carapace 4, leneth of abdomen 6:5, length of trochanter and femur of first lee 4, of second 6, of third 5, of fourth 6°5, of the femora alone in the order named 3, 5, 3, 3:5. Another specimen (No. 17) in Mr. Egeinton’s Collection shows no structural features not exhibited in the first and is much less perfectly preserved. The abdomen appears to be more evenly oval and less narrowed posteriorly. The entire animal, in fact, seems to resemble C. scaber of Scudder in shape. Approvi- mate measurements in mm.: Total length 12, length of carapace 4, width of cara- pace 4, length of abdomen 8, width of abdomen 5. In Mr. Madeley’s Collection there is a fairly well-preserved example showing the cucullus apparently entire. It has conyex lateral margins and rounded angles ; 40 TERRESTRIAL CARBONIFEROUS ARACHNIDA. its anterior and posterior borders are straight and parallel, and the plate does not expand towards its anterior border, as in existing genera, so that it may be described as transversely oblong. The carapace is a little wider than long, with the lateral borders convex, the widest poimt lying a little in front of the middle ; its surface 1s moderately vaulted, its anterior portion being distinctly but evenly curved downwards towards the edge to which the cucullus is hinged. A distinet but shallow constriction marks the junction of the carapace and abdomen. The latter is elongate and oval, rather wider than the carapace ; behind the widest point in front, the sides are slightly convex and converge gradually towards the posterior extremity, which shows indication of a median lobate excrescence. Portions only of some of the legs are preserved. Approvimate measurements tir mm. +: Total length 12°5; length of carapace 4°5, width about 5; length of cucullus 1, width 2°5; length of abdomen 8, width about 5. Thus these three specimens from Coseley, near Dudley, agree tolerably closely in dimensions. The type of C. scaber, Scudder, on the contrary, was larger, the total length being 15 mm., the length and width of the carapace 5°25 mm., the length of the abdomen 9°75 mm., and the width 6°25 mm. ‘These measurements may be instructively compared with those of Kustarachie sulcata, Melander, from the same locality, namely Mazon Creek, [linois, the total length bemg 15 mm. and the abdomen, without the “ pygidium,” 9mm., with a width of 7mm. ‘Thus there is the same close agreement between the American specimens as between the English examples. Genus POLIOCHERA, Scudder. 1838. ? Cryptostemma, Gucrin-Ménevyille, Rev. Zool., p. 10. 1884. Poliochera, S. H. Scudder, Proc. Amer. Acad. Arts Sci., vol. xx, p. 16, 1890. Poliochera, 8. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 444. Characters as above (p. 37). Poliochera alticeps, sp. nov. Plate II, fig. 6; Text-figure 14. Carapace elevated, convex from before backwards; the elevated area marked with a median groove ending behind in an impression, and an impression, probably muscular, far out on each side of this, a posterior curved groove passing on each side into a deeper impression defining the elevated area behind; the median length of the carapace about equal to its posterior width and as long as the anterior two large terga of the opisthosoma. Opisthosoma wider than the carapace, its width less than its length; the three large segments subequal in length; each marked apparently with two HAPTOPODA. A pairs of impressions, the anterior pair of the first small and widely separated, the posterior pair larger and closer together; those of the other terga equidistant from the middle line and in approximately the same straight line as the posterior pair of the first large tergal plate. Measurements in mm.—Total length, exclusive of cucullus and caudal elonga- tion, 5°59; length of carapace, excluding cucullus 2, width about 2°5; leneth of opisthosoma 3°5, width 2°8; length of first leg about 4°5, of third lee about 4. Coseley, near Dudley. Type and only known specimen in the Collection of Mr. Walter Egeinton (No. 6). This specimen, in a split nodule of clay ironstone, shows very clearly the dorsal surface with apparently the entire cucullus, portions of four pairs of ambulatory appendages and a short two-jointed caudal process. Fra. 14.— Poliochera alticeps, sp. n.; dorsal surface, showing the muscular impressions on the carapace and on the terga of the opisthosoma, six times nat. size.—Coal Measures; Coseley, near Dudley. W. Keeinton Collection. Although the type species of the genus Poliochera, namely P. punctulata, Scudder, shows no cucullus and is described as haying the carapace flat, I think it probable that P. alticeps belongs to the same genus. Apart from the convexity of the carapace P. alticeps may be distinguished by its much smaller size, P. punctulata measuring 15 mm. in total length, of which the carapace is 6. Order HAPTOPODA, nov. No constriction between the prosoma and the opisthosoma, these regions apparently movably jointed together ; the posterior end of the prosoma as wide as the anterior end of the opisthosoma. Carapace of prosoma approximately as wide as long, without trace of transverse grooves indicating segmentation. Opisthosoma longer than wide, narrowed posteriorly, rounded at the extremity, exhibiting in 6 4.2 TERRESTRIAL CARBONIFEROUS ARACHNIDA. one case ten terga on the dorsal side, and always a small anal operculum beneath the last, but on the ventral side. Thus eleven segments are traceable in the opisthosoma. The number of sterna is doubtful; but there appear to be at least nine, excluding the area between the coxe of the last pair of legs, the first sternal plate being large with a widely convex posterior edge and the last small and encircling the sides and lower edge of the anal operculum. Mandibles or chelicerze not fully known, but their basal segment elongate and porrect. Palpi short and pediform, consisting of six segments, the basal segment (maxilla) the largest, not concealed from below, and slightly divergent from its fellow of the opposite side. Legs of the first pair long, somewhat like those of the Thelyphonide, the terminal Fie. 15.—Plesiosivo madeleyi, gen. et sp. n.; dorsal Fria. 16.—Sugegested restoration of ventral surface of surface with appendages restored from several the same. specimens, four times nat. size.—Coal Measures ; Coseley, near Dudley. segments (protarsus and tarsus) converted into a seven-jointed tactile organ, apparently without a claw; the rest of the segments normal in number and structure. The remaining legs ambulatory, similar in form and in segmentation, each consisting of the normal seven segments characteristic of the Arachnida, the patella being short and the terminal segment (tarsus) undivided. Claws unknown. The basal segments large, those of the fourth lege the largest, separated in the middle line by an elongated sternal area which seems to expand behind between the coxee of the fourth pair. Sternal plates of prosoma unknown, except for a small triangular anterior sternal plate lyimg immediately behind the basal segments of the palpi, and between those of the legs of the first pair and partially also between those of the second pair. Position of generative orifice unknown. PLESIOSIRO. 45 I have established this new Order, named in allusion to the tactile nature of the legs of the first pair, for a genus of Carboniferous Arachnida which cannot be fitted into any other Order of extinct or existing forms. In some respects it coincides with the definition of the Opiliones, notably in the total absence of constriction between the prosoma and opisthosoma, and in the number and nature of the tergal plates of the opisthosoma, and could hardly, indeed, be excluded from that Order by the structure of the appendages as seen from the dorsal side, although differing from all its known members in the T'helyphonus-like modification for tactile purposes of the legs of the first pair. The structure of the anal segment 1s also like that of some Opiliones, e.g. Cyphophthalinus, but it is also like that of the Anthracomarti. The arrangement, however, of the sternal plates of the opisthosoma and the position of the basal segments (coxe) of the prosoma with regard to the sternal area of that region, so far as I can decipher them, are very different from what may be seen in the Opiliones. They may, indeed, be described as more in conformity with the normal and primitive than is exhibited in that Order, which in these particulars is the most specialised of all Arachnida, with the exception of the Acari. Family PLEStostRONID®, nov. Genus PLESIOSIRO, nov. Generic Characters.—Carapace high, narrowed in front, its anterior border produced into a median beak-like spiniform process; marked on each side by a longitudinal crest extending from a point close to its antero-lateral angle to its posterior border; the area external to these crests sloped abruptly down to the lateral edge; the area between the crests flattish and marked with a pair of lightly-curved crests, which arise at the base of the spiniform process, diverge, then converge, and meet a little in front of the posterior border ; posterior border straight. Opisthosoma narrowed posteriorly, the terea much wider than long, with straight posterior border, the last only being convex posteriorly. The sternal plate of the last, lying just in front of the transversely oval or subcircular anal operculum, strongly angled, the preceding two sterna progressively less strongly angled. Opisthosoma bordered laterally by an unsegmented ridge representing probably the pleural integument of this region. Palpi with second segment (trochanter) short ; third, fourth, and fifth segments longer and subequal in length; the sixth short and tapering. Legs longish, the femora and tibiz the longest segments; tibia of first compressed ; basal segment of terminal tactile portion of the limb much longer than the rest individually. Type Species.— Plesiosiro madeleyi, sp. nov. Ad TERRESTRIAL CARBONIFEROUS ARACHNIDA. Plesiosiro madeleyi, sp. nov. Plate II, fig. 5; Text-figures 15, 16. Integument finely granular. Carapace with its admedian crests finely beaded ; the lateral crests apparently smoother; three tubercles forming an oblique line in the posterior half of the area on each side between the crests; the posterior width of the carapace a little less than its median length, the latter a little greater than the length of the anterior five terga of the opisthosoma. Opisthosoma longer than wide, its width about equal to the length of the anterior six terga; a narrow median granular crest on the anterior seven terga, and a few large granules forming an irregular, oblique, abbreviated crest on each side. The eighth tergal plate considerably shorter than the seventh; the ninth and tenth much shorter than the eighth. First leg, excluding the coxa, about as long as the body; its femur about as long as the first four terga of the opisthosoma; and a little longer than the tibia; the tibia about twice as long as the patella; the basal segment (protarsus) of the terminal tactile portion longer than the other segments individually. Fourth lee with trochanter and femur about equal in length to the carapace. The four distal segments of the palpi about half the length of the carapace. Measurements in mm. (of type).—Total length 11:5; length and width of carapace 5; length of opisthosoma nearly 7, its width 5, length of first lee about 11. Coseley, near Dudley. Type in the Collection of the late Mr. William Madeley. This specimen shows the basal segments of the mandibles, the two palpi, one complete leg of the first pair, the femur, patella, and half the tibia of the third leg, the femur and patella of the fourth, and the femur of the second; the shape of the carapace and the tergal plates of the opisthosoma. Also the posterior sterna of the opisthosoma ; and the hollow spaces of the basal segments of the legs of the first pair. Other specimens in Mr. Madeley’s, Dr. Hind’s, Mr. Priest’s, and Mr. Hegeginton’s Collections show additional features which have made it possible to restore the dorsal surface tolerably completely. Details of the ventral surface are in no instance well preserved, the sterna and the genital area of the opisthosoma being in every case obscurely indicated. A specimen in Mr. Heeginton’s Collec- tion (No. 4) is noteworthy for being the only one to show ten distinct tergal plates on the dorsal side of the opisthosoma, the ninth and tenth in this specimen appearing as a single plate in the others, where the posterior end of the opistho- soma is preserved (PI. II, fig. 5). PHALANGIOTARBIDA. 5) Order PHALANGIOTARBI, Haase. 1890. Opiliones, sub-order Phalangiotarbi, E. Haase, Zeitschr. deutsch. geol. Ges., vol. xlu, p. 650. 1910. Phalangiotarbi, R. I. Pocock, Geol. Mag. [5], vol. vii, pp. 508—512. Carapace of prosoma unsegmented, bearing a single pair of median eyes near its anterior border. No constriction between the prosoma and opisthosoma, but the two regions apparently movably jointed together. ‘erga of the opisthosoma eight or nine in number and referable to two categories; the anterior five or six quite short and apparently movably jointed, the posterior three long and apparently fused, though the sutures between them persist. Sterna of the opisthosoma apparently only seven in number, the posterior three corresponding with the posterior three terga and the anterior four with the anterior six terga ; the first sternal plate triangular and wedged between the cox of the last pair of appendages of the prosoma. The genital orifice either just in front of or just behind this plate. The anal orifice small, subapical, and perhaps closed by an operculum representing a tenth segment. Legs, where known, alike in structure and con- sisting of seven segments, of which the fourth or patella is subequal in length to the third (femur) or fifth (tibia). Palpi, where known, very short, slender, and pediform. This Order is wholly extinct and is only known from the Coal Measures of Kurope and North America. Although this group has some structural poimts im common with the recent Opiliones, such as the single pair of eyes, the absence of constriction between the prosoma and the opisthosoma, the presence of probably ten segments in the opisthosoma and the simple, not chelate, palpi, I think it advisable, in the present state of our knowledge, to keep the two apart, the segmentation of the opisthosoma in the Phalangiotarbi being quite unlike that of the Opiliones. Family PHALANGIOTARBIDA. Phalangiotarlide, Haase and Pocock (references as above under Phalangiotarbi). Sternal area of prosoma relatively large and longitudinally elliptical, consider- wbly longer than wide. The cox of all the post-oral appendages radiating round it, with their distal margins overlapped by the edge of the carapace. Coxe of the palpi narrow, and in contact in the middle line in front; cox of legs of first par lying on each side of them and diverging obliquely forwards and outwards, not in contact with each other; those of the fourth pair diverging obliquely backwards and widely separated at their proximal ends and followed by a pair of coxa-like 46 TERRESTRIAL CARBONIFEROUS ARACHNIDA. sclerites separated by a narrow median suboblong area. Opisthosoma bearing eight tergal plates, of which the anterior five are short and nearly straight or shghtly recurved, indicating that the posterior border of the carapace was also straight from side to side; these are followed by the three normal large plates. With the exception of the three plates lying behind the sternum of the prosoma and the coxee of the legs of the fourth pair, the significance of which is obscure, the morphology of this Arachnid, judging from the figure, seems to be clear. Judging from the size of the sternum of the prosoma and the wide separation of the cox of the legs of the first and fourth pairs, Phalangiotarbus is the least specialised member of the Phalangiotarbi. Genus PHALANGIOTARBUS, Haase. 1872. Architarbus, H. Woodward, Geol. Mag., vol. ix, p. 385, pl. ix, fig. 1 a—b (mee Scudder). 1890. Phalangiotarlus, E. Haase, Zeitschr. deutsch. geol. Ges., vol. xlii, pp. 6388 and 650, pl. xxx, fig. 3. 1910. Phalangivtarbus, R. I. Pocock, Geol. Mag. [5], vol. vii, pp. 510 and 512. Fic. 17.—Phalangiotarbus subovalis (Woodward); ventral surface of the prosoma and dorsal surface of the opisthosoma exposed, three times nat. size-—Coal Measures; Lancashire. cw. p., coxa of palp; ca. 1, coxa of first leg; cv. 4, coxa of fourth leg. After H. Woodward, Geol. Mag., vol. ix, pl. ix, fig. 1. Characters as above. Type Species.—Architarbus subovalis, H. Woodward. Phalangiotarbus subovalis (H. Woodward). Text-figure 17. 1872. Architarbus subovalis, H. Woodward, Geol. Mag., vol. ix, p. 385, pl. ix, fig. 1 a—b. 1890. Phalangictarbus subovalis, E. Haase, Zeitschr. deutsch. geol. Ges., vol. xlii, pp. 638 and 650, pl. xxx, fig. 3. 1904. Architarbus subovalis, A. Fritsch, Paleoz. Arachn., p. 35, fig. 39. 1910. Phalangiotarbus subovalis, R. I. Pocock, Geol. Mag. [5], vol. vii, p. 510. GEHERAPHRYNUS. 47 The type and only known specimen of this species, which is known to me solely from the figure and description, is imbedded in an ironstone nodule from the Coal Measures of Lancashire. Family Ancutrarsipm, Karsch. Sternal area of prosoma small, and either subcircular or more usually narrow and elongate, the proximal ends of the coxe being close together; the distal ends of the cox not, or hardly, overlapped by the edge of the carapace. Coxe of palpi usually, at all events, entirely concealed from below by those of the legs of the first pair, which meet throughout their length in the middle line; only in Geratarbus do they appear to be in contact at their proximal ends, and diverge to a slight extent outwards, léaving a narrow space between. Coxe of legs of fourth pair also meeting, or almost meeting proximally behind the posterior end of the sternal area. Opisthosoma with eight or nine tergal plates. This family, in the sense in which I have recently defined it (Geol. Mag. [5], vol. vii, p. 512), contains several genera, of which only one, Geraphrynus, is known to be British, the others, namely, Architarbus, Scudder, Geratarbus, Scudder, and Opiliotarbus, Pocock, having been recorded from North America. Genus GERAPHRYNUS, Scudder. 1884. Geraphrynus, 8. H. Scudder, Proc. Amer. Acad. Arts Sci., vol. xx, p. 16. 1890. Geraphrynus, 8. H. Scudder, Mem. Bost. Soc. Nat. Hist., vol. iv, p. 445, 1904. Geraphrynus, A. Fritsch, Paleeoz. Arachn., p. 33 (in part). 1910. Geraphrynus, R. I. Pocock, Geol. Mag. [5], vol. vu, pp. 510, 512. Generic Characters.—Body typically wide, its width across the anterior half of the opisthosoma nearly half the total length. Carapace usually angular in front, with its anterior lateral margins convex and gradually diverging to the posterior lateral angles, where the plate is widest; its posterior border either evenly convex or produced posteriorly in the middle. A pair of median eyes near the anterior extremity. Opisthosoma with nine tergal plates, the first two or more following the curvature of the posterior border of the carapace; the sixth segment much shorter than the seventh, and generally a little, sometimes markedly, longer than the fifth. A suleus commonly traceable on each side of the terga, extending from a poimt not far from the postero-lateral angles of the carapace to the convex posterior border of the ninth plate, terminating one on each side of the anal orifice, and dividing the terga into three areas, a median and two lateral. The anal orifice subapical, and probably closed by a small opercular plate representing 48 TERRESTRIAL CARBONIFEROUS ARACHNIDA. the tergum of the tenth segment. Ventral surface of opisthosoma typically with seven sternal plates; the last three large and corresponding to the last three terga ; the anterior four corresponding to the anterior six terga. he first and second sterna small and visible in the mtercoxal space of the legs of the last pair, the first being triangular. Apparently a small orifice, the genital orifice, situated at the anterior extremity of the first and behind the sternal area of the prosoma. Sternal area of prosoma narrow, much longer than wide, and consisting of five small plates, one pair between the coxee of the legs of the third and fourth pairs, a second pair between those of the second legs and a small unpaired plate just behind the contiguous coxee of the legs of the first pair. Coxe of the four pairs of legs large, triangular, and wedge-shaped, occupying the whole ventral area of the prosoma, with the exception of the narrow sternal region ; each leg consisting of seven segments, including the coxa; the second Fia. 18.—Geraphrynus carbonarius, Scudder ; diagrammatic restoration of the dorsal surface of the type specimen, adapted from Scudder’s figure (Proc. Boston Soc. Nat. Hist., vol. iv, pl. x, fig. 10), the dotted lines representing the coxal and sternal sclerites underlying the carapace, nearly three times nat. size. —Coal Measures; Mazon Creek, Illinois, U.S.A. segment (trochanter) stout but short; the remaining segments thinner and longer, and not very unequal in length, with the exception of the seventh or tarsus, which is quite short, the fourth segment or patella being long, and not short as in the Opiliones. Palpi very short, probably six-jointed, their basal segments concealed from below by the united coxe of the legs of the first pair. Type Species—Geraphrynus carbonarius, Scudder. This generic diagnosis is based for the most part upon the British material of this genus that I have seen, checked by comparison with Scudder’s figure of the type specimen of the typical species of the genus, G. carbonarius. Judging from this figure, G. carbonarius differs from all those described in this paper in the large size of the carapace as compared with the opisthosoma, the median length of the former exceeding the median length of the latter. It is impossible to say with certainty how many species are represented by the GERAPHRYNUS. 49: material from Dudley that I have seen. he following six, which may be determined by the subjoined key, appear at least to be distinguishable forms : a. Carapace as wide as long or wider; length of the anterior four sternal plates of the opisthosoma much less than that of the posterior three. b. The posterior border of the carapace markedly sinuous, its lateral portions being slightly concave and its median portion convexly produced in the middle line. ec. Opisthosoma longer and narrower in its posterior portion, the width of its penultimate segment about equal to the median length of the carapace ; the posterior border of the seventh and eighth terga distinctly angled angulatus. ce’. Opisthosoma shorter and wider in its posterior portion; the width of the penultimate segment considerably exceeding the median length of the carapace. : : : : : hindi. b’. The posterior border of the carapace not markedly sinuous, either evenly convex or with its lateral portion nearly straight and no rounded median backwardly bulging area. d. Posterior border of carapace evenly convex from side to side; opisthosoma short, its greatest width nearly equal to its median length; no trace of tubercles on the anterior terga of the opisthosoma : eqgintoni. d’. Posterior border of carapace with its median area nearly straight, trans- verse, its lateral portions also nearly straight and inclined obliquely inwards and backwards from the angles ; opisthosoma long, its greatest width only equal to the median length of the anterior eight segments; a pair of tubercles in the middle of the anterior six terga 5 . tuberculatus. a’, Carapace distinctly longer than wide; width of the anterior four sternal plates of the opisthosoma nearly equal to the length of the posterior three. e. Width much more than one-third of the total length; anterior four terga of opisthosoma sinuous : ; angustus. e’. Width about one-third of the total length; only the anterior two terga of the opisthosoma sinuous ‘ ; : 5 torpedo. Geraphrynus angulatus, sp. nov. Plate III, fig. 2; Text-figures 19, 20. Carapace closely granular, with median eyes distinct and placed apparently on a tubercle which has a convex anterior border ; its posterior width a little exceeding its median length; its posterior border produced and conyexly rounded in the middle, its sides slightly concave ; the median area of the carapace about equal to that of the anterior eight tergal plates of the opisthosoma. The median area of the first two terga of the opisthosoma almost obliterated and overlapped by the median backward projection of the carapace; the posterior border of the third nearly straight; no large tubercles traceable upon the middle of the anterior six terga; the median length of the sixth a little exceeding half that of the seventh and a little less than half the median length of the eighth; the median length of the latter about half that of the ninth, the anterior width of the ninth rather less than two-thirds that of the sixth; the median length of the ninth about equal to its ford ( 50 TERRESTRIAL CARBONIFEROUS ARACHNIDA. anterior width. The posterior borders of the seventh and eighth distinctly angled inthe middle line. On the seventh, eighth, and ninth terga a distinct integumental eroove running from the anterior to the posterior border and representing apparently the external of the two pairs of grooves seen in other species, the internal grooves dividing the terga into three definite areas being invisible in G. angulatus. First sternal plate of opisthosoma much longer than the second or third in the middle line; its posterior border emarginate ; the second short, its median length about one-fourth its posterior width, narrower laterally, its anterior border fitting into the emargination of the posterior border of the first; the third only a little longer than the second in the middle line, its anterior borders lightly biangulate, Fia. 19.—Geraphrynus angulatus, sp.n.; dorsal surface with appendages, four Fra, 20.—Ventral surface of times nat. size.—Coal Measures ; Coseley, near Dudley. Wheelton Hind the same. Collection. its median length about half that of the fourth; the fourth, fifth, and sixth increasing gradually but slightly in length, but the sixth only a little longer than the fourth and barely two-thirds the length of the seventh. Leg of first pair with trochanter, femur, patella and tibia about equalling the carapace in length; the same segments of the fourth leg equalling the last five terga or four sterna of the opisthosoma; the spiniform process on the distal inferior edge of the femora and patellze apparently smaller than in other species (e.g. G. hindi) where they are shown. Measurements in mm.—Total length 16; median length of carapace 6, width of latter 6°5; median leneth of opisthosoma about 10; width of the latter 7:5; length of sternal surface of opisthosoma 13; length of first leg from base of trochanter to end of tibia 5°5; the same segments of the fourth leg 9-5, GERAPHRYNUS. 5] Coseley, near Dudley. Type and only known specimen in the Collection of Dr. Wheelton Hind, Geraphrynus hindi, sp. nov. Text-figures 21, 22. Cavapace of about the same shape as in (. angulatus. The anterior five terga of the opisthosoma more sinuous transversely, the lateral portion of the anterior borders slightly convex and the median areas slightly concave. In G. angulatus the third is scarcely sinuous, and the fourth is straight transversely. The posterior portion of the opisthosoma relatively much wider than in G. angulatus ; the posterior border of the penultimate or eighth sternal plate about as long as the carapace and Fig. 21.—Geraphrynus hindi, sp. n.; dorsal surface Fia. 22.— Ventral surface of the same. with palpi and legs of first and third pairs, four times nat. size—Coal Measures; Coseley, near Dudley. Wheelton Hind Collection. a little greater than the median length of the eighth and ninth sternal plates ; the posterior width of its median area much greater than its length. In G. angwlatus, on the other hand, the posterior width of the plate is much less than the length of the carapace or than that of the eighth and ninth sterna, and the posterior width of its median portion is about equal to its length. Legs much longer than in G. angulatus, the trochanter, femur, patella and tibia, 1%. e. the second, third, fourth, and fifth segments of the third leg, exceeding the median length of the opisthosoma. In G. angulatus these same segments in the fourth leg are much shorter than the median leneth of the opisthosoma, and since the fourth leg in this genus is longer than the third, it is evident that the segments in question in the fourth leg of G. hindi would greatly exceed the median length of the opisthosoma. t bo TERRESTRIAL CARBONIFEROUS AKACHNIDA. A, Measurements in mm.—Total length 13; length of carapace 5, width 5°5; median length of opisthosoma 8, width of opisthosoma 7; length of ventral surface of opisthosoma from apex of first sternal plate 11; length of first leg, excluding coxa, 8, of third leg 11. Coseley, near Dudley. ‘T'ype and only known specimen in the Collection of Dr. Wheelton Hind. Geraphrynus tuberculatus, sp. nov. ‘T'ext-figure 25. Carapace thickly and closely granular, short, much wider than long, its median length about equal to that of the first seven tergal plates of the opisthosoma ; its Fig. 23 —Geraphrynus tuberculatus, sp. n.; dorsal surface, four times nat. size.—Coal Measures; Coseley, near Dudley. W. Eeginton Collection. posterior border straight and transverse, in no sense convex, in the middle, almost straight and inclined obliquely forwards and outwards at the sides. The anterior six tergal plates of the opisthosoma each with a pair of distinct tubercles in the middle; the first and second curved round the posterior edge of the carapace; the third with its posterior border nearly straight; the median area of the first quite distinet ; the sixth nearly twice as long as the fifth, and about half the length of the seventh or eighth; the latter about two-thirds the length of the ninth, the anterior width of which is about two-thirds the width of the sixth; the length of the ninth about three-quarters its anterior width. The posterior borders of the median area of the seventh and eighth terga straight, not angled. Ventral surface and appendages unknown. Measurements in mm.—Total length 18; length of carapace 6, width nearly 8; median length of opisthosoma 12, width of opisthosoma 8°5. GERAPHRYNUS. Or & Coseley, near Dudley. Type in the Collection of Mr. Walter Hgginton (No. 46). Mr. Eveinton’s Collection also contains a specimen measuring about 20 mm. long, which possibly belongs to this species, but is not sufficiently well preserved for description. Geraphrynus eggintoni, sp. nov. Text-figures 24, 25. Carapace about as wide as long; its median length about equal to that of the anterior eight tergal plates of the opisthosoma; its posterior border convex in the middle, but not produced, its lateral portion not concave or sinuous. Median area of first and second tergal plates of opisthosoma very narrow; posterior border of the third straight; the sixth nearly twice the length of the fifth, and about half Fig. 24.—Geraphrynus eggintoni, sp. n.; dorsal surface Fic. 25.—Ventral surface of prosoma and of anterior with appendages, four times nat. size.— Coal somites of opisthosoma of the same. Measures ; Coseley, near Dudley. W. Egeinton Collection. that of the seventh; the posterior border of the seventh and eighth straight ; median area of seventh and eighth subequal and about two-thirds that of the ninth, the anterior width of which is about three-fourths the width of the seventh, and much greater than the median length of the nmth. On the ventral surface the first sternal plate seems to be much shorter in the middle line than in G. angulatus or Gr. hindi, owing to its deeper emargination; the second also is shorter than in the former species, more produced mesially in front and more emarginate behind, while the third is apparently much longer, being in fact as long in the middle line as the fourth. Legs short, that of the first pair with its trochanter, femur, patella and tibia about equal to the length of the carapace; the spines on the femur and patella well marked; trochanter, femur and patella of the third about equal to the carapace; the same segments and the tibia of the third about equal to the last five segments of the opisthosoma. Measurements in mn.—Total length 12; length and width of carapace 5; median D4 TERRESTRIAL CARBONIFEROUS ARACHNIDA. length of opisthosoma 7, width of the latter about 6; length of first leg from base of trochanter 7, same of the third leg 8. Coseley, near Dudley. Type and only known specimen in the Collection of Mr. Walter Egginton. This species has the legs short as in G. angulatus, but differs in the shape of the posterior border of the carapace, and of the seventh and eighth terga of the opisthosoma, this region also being shorter and broader than im that species. From (@. hindi it differs in the shortness of its legs and the shape of the posterior border of the carapace, and from G. tuberculatus m its longer carapace, shorter opisthosoma, shape of the posterior border of the carapace, etc. Geraphrynus torpedo, sp. nov. Plate III, fig. 1; Text-figures 26, 27, Body long and narrow, nearly four times as long as wide. Carapace about Fic. 26.—Geraphrynus torpedo, sp. n.; dorsal surface, Fic. 27.—Ventral surface of the same. about four times nat. size.—Coal Measures ; Coseley, near Dudley. W. Egginten Collection. one-third longer than wide, its median length about equal to that of the anterior eight terga of the opisthosoma, its width about equal to the length of the ninth and half the eighth terga, and therefore much less than half the length of the opisthosoma; its posterior border evenly convex. Opisthosoma nearly twice as long as wide, its width across the seventh tergum a little exceeding the length of the eighth and ninth terga; the first and second terga very narrow in the middle line, the median area of the first obliterated or overlapped by the posterior border of the carapace, the third, fourth and fifth straight and subequal in length, the fifth about half the length of the sixth, which is a little more than half the length of the seventh, the latter about equal to the eighth, and both of them shorter than the ninth. Fifth and sixth sterna of the opisthosoma subequal in length and shorter than the seventh; the sternal plate, corresponding to the third in the typical species of Geraphrynus, as long as the fourth and marked by a transverse ridge ; ANTHRACOMARTI. 55 the second segment also long, with the median area of its anterior border con- siderably produced to fit into the correspondingly deep emargination of the first triangular intercoxal sternal plate. Coxal area of prosoma about one-fourth longer than wide. Leg of first pair apparently shorter than the carapace, which is about as long as the trochanter, femur, patelia and tibia of the fourth leg. Measurements in mm.—Total length 12; carapace almost 5, width of carapace 3; length of opisthosoma 7, width about 4; length of its last three segments about 5; of sternal area of opisthosoma nearly 10; width of coxal area of prosoma 3:0 ; length of fourth leg almost 7. Coseley, near Dudley. Type and only known specimen of this aberrant species in the Collection of Mr. Walter Egeinton (No. 10). Geraphrynus angustus, sp. nov. Allied to the last but shorter; body about two and a half times as long as wide. Carapace about one-fourth longer than wide, median length equal to that of the anterior eight terga of the opisthosoma, its posterior border evenly and widely convex. Opisthosoma much less than twice as long as wide, its width about equal to the last three tergal plates; the first, second, third and fourth terga sinuously curved round the convex border of the carapace; the median area of the first obliterated, of the second very short; the anterior border of the fifth sinuous ; the plate about half the length of the sixth, which is more than half that of the seventh ; seventh and eighth subequal and each about three-quarters the length of the ninth. Measurements in mm.—Total length 9°5 ; length of carapace 4, width 2°5; length of opisthosoma 5°5, width 3°8; length of sternal area of opisthosoma 7:5. Coseley, near Dudley. A single specimen in Mr. Walter Egginton’s Collection (No. 36, one half labelled also 26). In addition to its greater width as compared to its length, a character in which it serves in a measure to bridge over the interval between G. torpedv and the more normal species of Geraphrynus, this new species differs from G. torpedo in the sinuous curvature of the anterior four terga of the opisthosoma. Order ANTHRACOMARTI, Karsch. 1882. M. Roemert, M. chimera, var. Sulweyi, var. semi-spinosus, M. leintwardinensis, var. dicipiens. I. A. 1. (a): Monograptt in which the thece are uniform, and the polypary has dorsal curvature. é. Monograptus cyphus, Lapworth. Plate XXXVI, figs. la 1876. Monograplus cyphus, Lapworth, Geol. Mag., dec. ii, vol. iii, p. 352, pl. x1i, figs. 3a and 3e. Polypary several cm. in length, shghtly arcuate distally with either involute or broadly recurved proximal portion, widening persistently from a long and conspicuous sicula to a maximum diameter of 1:5 mm. Thece ten to nine in 10 mm., simple tubes with even apertural margins, overlapping one- third of their length near the sicula, and as much as two-thirds in the more mature portions of the polypary. Description.—The form of the polypary, with the broad sweeping curve of the early portion, is highly characteristic, but the amount of curvature varies some- what in different individuals, bemg rather more abrupt in some than in others. The sicula alone forms the proximal termination of the polypary; it is fairly robust and very long, measuring fully 4mm. in length; its apex lies about midway MONOGRAPTUS. 363 between the apertures of th. 1 and th. 2, and the first theca (th. 1) arises about one-third of the way along its length. Fias. 236 a—c.—Monograptus cyphus, Lapw. WN a Vy \\ I A\ — y. = a ——= a a. Proximal end, showing sicula. Group. Coll. O. 'T. Jones. b. Ditto, in full relief. Same locality. c. Proximal end, showing abrupt curvature. Coll. Geol, Survey of Scotland. Birkhill Shales. Rheidol Gorge, Cardiganshire ; Rheidol All the thece are simple, straight - walled, narrow tubes, with normal aper- tural margins which may §) appear slightly concave or even convex after com- ge Gi pression; in their general y characters they resemble A those previously described Re as characteristic of the De Dichograptide ; they have a length of 3 mm., and are about six times as long as wide. The amount of over- lap increases steadily from Garple Linn, Moffat; Lower ONe-third of their length near the sicula to one-half in the broadly recurved portion, and eventually to two-thirds of the total length in the mature portion of the polypary, where a horizontal lme drawn through Fries. 236 d and e.—Monograplus cyphus, Lapw. d d. Thece near the proximal end of the polypary. Dobb’s Linn; Lower 3irkhill Shales. Coll. Lapworth. e. Distal thecx of same specimen. The apertural margins in the mature portion lie obliquely an aperture would cut three different thece. with respect to the general direction of the poly- pary, but are in every case normal to the theca itself. of the thecz is clearly seen, but occasionally, as In specimens preserved in relief the overlap the result of compression, the thecee appear some- what like those characteristic of Climacograptus, and the overlap is then apparently less (Pl. XXXVI, fie. La). Affinities. —Monog. cyphus resembles in its general form several other members of the group; it may, however, be readily distinguished by the breadth of the distal portion of the polypary, and the simple character and extensive overlap of its thece. Distal fragments may resemble fragments of Monog. leptotheca, but the polypary of M. cyphus is more curved, and the overlap of the thecze less for a given breadth of stipe. Horizon and Localities. —Llandovery (Birkhill Shales), zone of JZ. cyphus. S. Scotland: Waterfall, Long Linn, Dobb’s Linn, Moffat; Garple Linn, Moffat ; 364 Lockerbie ; Duffkinnell. Criccieth; Rhayader; Pont Erwyd, etc. below Slate Quarry, Pomeroy. Lake District: Skelgill. BRITISH GRAPTOLITES. Wales: Llanystwmdwy, near Ireland: Donaghadee; Mill Sluice Associates, ete.—Monog. cyphus is an abundant and characteristic fossil in the Birkhill Shales of 8. Scotland and their equivalents elsewhere, lying immediately below the zone of Monog. gregarius (sub-zone M. fimbriatus). Lt commonly occurs associated with Monog. revolutus and var. austerus, M. Sandersoni, M. atavus, Dimorphog. physophora, Climacog. rectangularis, and other forms. phog. puyso} p g Y , Collectors.—Lapworth, Jones, Fearnsides, and the Authors. Monograptus acinaces, ‘l’érnquist. Plate XXXVI, figs. 2 a—e. 1899. Monograptus acinaces, Tornquist, Monograptide of Scanian Rastrites Beds, Lunds Univ. Arsskrift, vol. xxxv, pt. 2, no. 1, p. 5, pl. i, figs. 7, 8. 1909. Monograptus rheidolensis, Jones, Quart. Journ. Geol. Soc., vol. Ixv, p. 535, figs. 19 a—c. Polypary several cm. in length, approximately straight distally but arcuate in proximal portion, very slender at first, but increasing in width till a maximum Fias. 237 a- d.—Monograptus acinaces, 'Tornq. A \ \h vy ve Yat t 7 it ay | ¥| A Yi "hy \ Va] \i} CA\ a H ‘i ( | a , ot a | Cy NV | hh a i} Me SE i i) , Ay if \ ; \ hi (\4 | WE aL | iis vs a if c d a. Proximal end, showing sicula. Figured as M. rheidolensis, Quart. Journ. Geol. Soc., vol. Ixy, fig. 19b. Rheidol Gorge, Car- diganshire; Rheidol Group (zone of M. rheidolensis). Geol. Survey of England and Wales, Jermyn St. (23705). b. Thece in median portion of the polypary. Enlargement of part of Pl. XXXVI, fig. 2a. c. Distal thece Rheidol Group. in relief. Rheidol Gorge; Coll. O. T. Jones. d. Distal thece in relief. Figured Quart. Journ. Geol. Soce., vol. Ixv, fig. 19d. Geol. Survey of England and Wales (23704). cone eleven in 10 mm., those of the proximal mm. is attained. Thecx six to portion very long slender tubes over- lapping about one-half their length, those of the distal portion expanding somewhat in the apertural region and overlapping two-thirds their length. Description.—The arcuate proximal portion of the polypary with its very long slender thecz is highly characteristic of this species ; distally the curvature becomes less and may eventually disappear altogether. The poly- pary is of great but unknown length, probably reaching 30 cm. at least. Small fragments in which the maximum width is not attained are those of commonest occurrence. The sicula is very long and slender, measur- ing 5mm. in length and reaching to half-way between the apertures of th. 1 and th. 2; it alone forms the termination of the polypary, some distance above the since th. 1 arises aperture of the sicula. The whole proximal end of the polypary is extremely slender, and the thecee are very long (4—5 mm.), growing approximately parallel with the general MONOGRAPTUS. 365 direction of the polypary; they overlap about one-half their length, and are about twenty times as long as broad; the apertural margins are even and approximately horizontal. In the more distal portion of the polypary the thecz are about the same leneth, but are only ten times as long as broad, have a higher inclination, and overlap for fully two-thirds of their length; they expand somewhat in the apertural region and as a result the walls show a tendency to slight curvature ; the apertural margins are even and eyerted. The thecx are so slender even in the distal portion that a horizontal lme drawn across the polypary at any point would cut three different thecz at least. Remarks.—Tornquist, in his original description of this species, stated that he was unacquainted with the distal extremity of the polypary. The British form here described agrees so closely with Térnquist’s species as regards the proximal end that it is practically certain that the two are identical; the features of the thecee of the distal portion of the polypary are, however, so striking and distinct from those of the proximal portion that the British specimens were described by Jones as a new species—Monog. rheidolensis. Affinities.—In the length of the thec, their slender nature and amount of overlap, Monog. acinaces approaches M. leptotheca, with which it seems to have been formerly confused ; the distal thecee of M. leptotheca, however, show no such characteristic expansion in their apertural regions, and are even more slender than those of M. actnaces. Horizon and Localities—Ulandovery (Birklill Shales), zone of M. cyphus. C. Wales: Rheidol Gorge. S. Scotland: Waterfall, Long Linn, Dobb’s Linn, ete. Associates, etc.—Monog. acinaces appears to be a fairly abundant fossil in the zone of M. cyphus, especially in the Pont Erwyd district, where Jones records it in a band below that in which M. cyphus is most abundant. It has also been found in 8. Scotland in the zone of AL. cyphus. Collections.—Jones, Lapworth, and Geological Survey of Hngland and Wales. Monograptus gregarius, Lapworth. Plate XXXVI, figs. 3a—d. 1851. = Graptolites Nilssoni, Harkness, Quart. Journ. Geol. Soc., vol. vii, p. 61, pl.i, figs. 7 a—d. 1858. Graptolites Nilssoni (pars), Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 537, pl. xx, fig. 19. 1876. Monograptus gregarius, Lapworth, Geol. Mag., dec. ii, vol. ui, p. 317, pl. x, figs. 12 a—e. 1876. Monograptus gregarius, Lapworth, Cat. West. Scott. Foss., pl. 1, fig. 7. 1877. Monograptus yregarius, Lapworth, Proc. Belfast Nat. Field Club, p. 181, pl. v, fig. 4. 1892. Monograptus gregarius, Tornquist, Siljansomr. Graptol., Acta Univ. Lund., vol. xxviii, p. 8. 1897. Pristiograptus gregarius, Frech, Leth. Geogn., pt. i, vol. i, pl. i, figs. 3—5, p. 660, fig. 215. 1899. Monograptus gregarius, Tornquist, Monograptide of Scanian Rastrites Beds, Lunds Univ. Arssk., vol, xxxv, pt. 2, no. 1, p. 4, pl. i, figs. 1—6. 366 BRITISH GRAPTORITES. Polypary short, arcuate, with an average length of 3 em. and uniform breadth of about *75mm, Sicula very conspicuous and of great length. Thee ten in 10 mm., simple tubes with even apertural margins lying perpen- dicularly to the general trend of the polypary, overlap increasing from mere contact to one-third of thecal length. Description.—The gregarious habit of this species is highly characteristic, slabs of rock being covered with its small stiffly curved polyparies. The proximal end appears unusually robust on account of the extent and size of the sicula, which measures fully 5 mm. in Fias. 288 a and b.—Monograptus gre- Teeny Ota length, and which reaches up to the level of the SA aperture of th. 5, whence it gradually merges into WT the virgula; since th. 1 arises a little distance , et : : \ My above the aperture of the sicula, the sicula together af y with five thecee form the proximal portion of the \.4 ‘2 polypary. Ne Pi : i a Ab } ( The thecee show a distinct tendency to expand ba re in the direction of the aperture. 4 i\ Affinities—The stiffly curved polypary and the he &\ z : fi i robust character of the proximal end, together with fi \ the disposition of the relatively gigantic sicula, ff ha . i 3 > . ys \ should serve readily to separate this species from 7 ‘i ; F f \ any other Monograptus. Distal fragments, how- r . ever, have sometimes a superficial resemblance to ee D those of M. intermedius when badly preserved, a. Proximal end, showing sicula. Dobb’s Ess yea Sele - SANE 5 5 Lee aay Linn, Mid’ Bakbill Shales. Co though the thecz of the latter species are diferent Lapworth, sae in form. b. Specimen in relief, showing sicula. : ae d ; Ibid. ? Horizon and Localities —Llandovery (Birkhill Shales), zone of M. gregarius. S. Scotland: Dobb’s Linn; Beleraig Burn; Garple Linn; Frenchland Burn ; ete. N. Ireland: Coalpit Bay, Donaghadee: Wales: Twymyn River, near Llanbrynmair; Rhayader; etc.; Pont Erwyd; ete. Lake District: Skelgill ; Browgill; Stile End. Associates, ete.—Monog. gregarius is one of the commonest fossils in the Llandovery wherever the graptolitic facies is developed; it occurs in swarms as a general rule, and is often associated with Monog. jfimbriatus, M. communis, M. triangulatus, Rastvites approaimatus, Glyptog. sinuatus, G. tamariscus, Climacog. Tornquisti and other forms. Collections. — Geological Survey of Scotland, Sedgwick Museum, British Museum (Natural History), Lapworth, Fearnsides, Jones, and the Authors, ete. MONOGRAPTUS. 367 JT. A. 1. (b): Monograpti m which the theese are uniform and the polypary shows ventral curvature. Monograptus bohemicus (Barrande). Plate XXXVI, fies. 4 a—d. 1850. Graptolithus bohemicus, Barrande, Graptolites de Bohéme, p. 40, pl. i, figs. 15—18. 1851. Graptolithus bohemicus, Suess, Ueber Bohmische Graptolithen, pp. 110—111, pl. vin, figs. 6 a—e. 1851. 2 Graptolithus Barrande’, Scharenberg, Ueber Graptolithen, etc., Inaug. Dissert. (Breslau), p. 15, pl. i, figs. 5—5 a. 1852. Monograptus bohemicus, Geinitz, Die Graptolithen . . . der Grauwackenformation in Sachsen, p. 36, pl. u1, fig. 4. 1869. traptolithus bohemicus, Heidenhain, Zeitschr. d. deutsch. geol. Gesellsch., vol. xxi, p. 149, pl. i, figs. 4 a—e. 1881. Graptolithus scalaris, Quenstedt, Petrefactenkunde Deutschl., vol. vi, pl. cl, fig. 44. 1883. Monograptus bohemicus, Tullberg, Skanes Graptoliter, pl. iii, figs. 3—5. 1884 Monograptus bohemicus, J. D. La Touche, Handbook to the Geology of Shropshire, p. BR Ui lls. pl. xviii, fig. 573. 1889. Pristiograptus bohemicus, Jackel, Zeitschr. d. deutsch. geol. Gesellsch., vol. xl, p. 672, pl. xxvii, figs. 3—6. 1890. Monograptus bohemicus, Geinitz, Die Graptolithen d. k. Min. Mus. in Dresden, p. 14, pl. a, fig. 10. 1897. Pristiograptus bohemicus, Frech, Leth. Geogn., vol. i, pt. 11, p. 644. 1900. Monograptus bohemicus, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 483, text-fig. 25, pl. xxv,° figs. 27 a and 27 B. Polypary several cm. in length, straight distally, with broad concave sweep in the proximal portion, widening steadily till a maximum breadth of 2mm. is attained. Thecz eleven to nine in 10 mm., simple short tubes with a maximum length of about 2 mm., two to three times as long as wide, overlapping one-third to one-half their length; average inclination 30—35° ; apertural margins wide. Description.—-The broad sweep of the polypary in the proximal region is highly characteristic of the species, and in small individuals the whole polypary appears to share in the curvature, the straight distal portion being only seen in long specimens. The sicula is usually conspicuous; it has a length of about 1 mm. and its ereat width in the apertural region gives a distinctive character to the proximal end as a whole ; the virgella is usually stout. The thecee are short and broad tubes quite simple in character, though im the concave portion of the polypary the breadth of the apertures often induces impres- sion of the ventral wall of the theca lying next above, giving a characteristic appearance to the polypary after compression. 4.9 Lam 368 Fras. 239 a—e.—Monograptus bohemicus (Barr.), P Jy ik ae 4 Poa ‘ere pe. of €, a eS i t / 7 44 gd AY ) oa hes Wf hey j j Ney y <} ¢ ed A» | i AY j gx | pe Me be 4 ys 1a €\ ys" Sw eon8 ‘i a Ore 1 a b c a, Proximal end, showing sicula. Figured Quart. Journ. Geol. Soc., vol. lvi, p. 484, fig. 25b. Elton-Ludlow Road; Lower Ludlow Shales. Coll. Wood. b. More distal thece in relief. Figured Quart. Journ. Geol. Soe., vol. lvi, p. 484, fig. 25 a. River Irfon, Builth; Lower Ludlow Shales. Coll. Wood c. Thee of extreme distal portion. Enlarge- ment of part of Plate XXXVI, fig. 4 d. BRITISH GRAPTOLITES. Affinities. —Monog. bohemicus isa perfectly distinct and well-marked species which should not be confounded with any other Monograptus. Horizon and Localities —Lower Ludlow Shales (zone of M. Nilssoni). Lake Dis- trict: Helm Knot, Dent, ete. Wales: Dee- side Slab Quarries, Moel Ferna. Welsh Borders: Aberedw Hill, Builth ; River Ivfon, Builth; Vicarage Road, Builth, ete. Ludlow District: Elton Lane ; Klton-Evenhay Lane ; Klton-Ludlow Road, ete. Associates, ete.—Monog. bohemicus is a fairly common fossil in the Lower Ludlow Shales of many localities, but especially in the zone of J/. Nilssoni. zone associated with Mouog. Nilssoni, M, It oceurs in this colonus, M. varians, and Gothog. spinosus ; and with M. scanicus, M. chimaera, and M. tumescens at higher horizons. Collections.—Sedewick Museum, Lapworth, and the Authors, ete. ro) 5) 5} ’ Monograptus concinnus, Lapworth. 1876. Plate XXXVI, figs. 5 a—e. Monograptus concinnus, Lapworth, Geol. Mag., dee. ii, vol. ii, p. 320, pl. xi, figs. 1 a—e. Polypary several cm. in length, with incurved proximal portion and slight ventral curvature distally, gradually widening from a slender proximal end to an average breadth of 1 mm. Thece twelve to ten in 10 mm., simple short tubes expanding in the apertural region, overlapping one- third to one-half their length, and with wide, even and everted apertural margins. Description.—The polypary appears to be always more or less curved, but the curvature is perhaps most pronounced proximally ; it widens gradually from a very slender proximal termination, but maintains a uniform breadth for a con- siderable distance in the distal portion. The thecee are short, broad tubes, about 1°5 mm. in length in the maturer part of the polypary, and in many respects resemble those of M. nudus, the appearance of an excavation being heightened by the ventral curvature of the polypary. Affinities—Monog. concinnus may always be distinguished by the form of the polypary with its pronounced curvature, which contrasts effectively with the straight and rigid form of M. nudus. Fragments of MM. concinnus, however, MONOGRAPTUS. 369 ed meee a coneinnus, strongly resemble those of M. Nilssoni, but may be distinguished by the more closely set Ms eC thecz and by the different curvature of the be proximal portion of the polypary. Horizon and Localities —Llandovery (Birk- iv M7 W Pf ill Shales), zones of M. gqregarius to M. « ? \ |AK, = 6s) tie F sf a Sedgwickii. 8. Scotland: Dobb’s Linn; Bel- } y he craig Burn; Garple Linn, ete. Wales: Pont v ial Erwyd (various localities); Pary’s Mountain, yer e S| i. Anelesea. Lake District: Skeleill, ete. \\ yf to) = 9 \ ie F ; v } Associates, etc.—Monog. conciinus appears first inthe M. gregarius zone, but 1s commonest in the zones of M. convolutus and M. Sedqwicki, _ where it 1s associated with Monog. convolutus, a. Thece of proximal portion. Part of speci- . ; ae = men on same slab as Pl. XXXVI, fig. 5b. M. fens, M. Sedgwicku, Cephalog. cometa, b. Ibid. : : ¢. Distal thece. Enlargement of part of Glyptog. serratus var. barbatus, and other forms. Pl. XXXVI, fig. 5e. . , ; : ‘ : d. Distal thece in relief, probably referable to Collections.—Geological Surveys of Scot- this species. Rheidol Gorge, 420 yds. ESE: of Bryn-chwith Farm Louse, Pont land, and of England and Wales, Jones, Greenly, Erwyd, Cardiganshire. Geol. Survey of mee lamd avid Wales Lapworth, and the Authors. I. A. 1. (¢): Monograpti in which the thecz are uniform and the polypary has dorsi-ventral curvature. e Monograptus Nilssoni (Barrande). Plate XXAVII, figs. 1 «a 1850. Graptolithus Nilssoni, Barrande, Grapt. de Bohéme, p. 51, pl. i, fig. 16. 1852. Monograptus Nilssoni, Geinitz, Die Graptolithen . . . der Grauwackenformation in Sachsen, p. 35, pl. ii, figs. 17—20, 24, 25, 28—32 (?). 1869. Monograptus Nilssoni, Heidenhain, Zeitschr. d. deutsch. geol. Gesellsch , vol. xxi, p. 147, pl. 1, fe 2. 1876. Monograptus Nilssoni, Lapworth, Geol. Mag., dec. ii, vol. iti, p. 315, pl. x, figs. 7 a—e. 1876. Monograptus Nilssoni, Haupt, Die Fauna des Graptolithengesteines, p. 21, pl. iv, fig. 3 (?). 1878. Monograptus Nilssoni, Kayser, Die altesten Devon-Ablagerungen des Harzes, p. 217, pl. xxxi, fig. 12 (fig. 25 ?). 1883. Monograptus Nilssoni, Tullberg, Skanes Graptoliter, pl. i, figs. 31, 32. 1884. Monograptus Nilssoni, J. D. La Touche, Handbook to the Geology of Shropshire, p. 78, pl. xviul, fig. 576. 1885 ?. Monograptus scanicus, Roemer, non Tullberg, Lethea Erratica, pl. ix, figs. 13 a, b. 1889. Pristiograptus Nilssoni, Jaekel, Zeitschr. d. deutsch. geol. Gesellsch., vol. xli, p. 673, pl. xxviii, Blom de 1890. Monograptus Nilssoni, Geinitz, Die Graptolithen d. k. Min. Mus. in Dresden, p. 13, pl. a, fig. 7 (an part), non fig. 8. =~ 370 BRITISH GRAPTOLIT KS. 1297. Linograptus Nilssoni, Frech, Leth. G2ognu., vol. 1, pt. 11, p. 662, fig. 218. 1899. Monograplus Nilssoni, Perner, Etules sur les Graptolites de Bohéme, pt. iii, sect. b, p. 7, pl. xvi, oes. 1, 2,7. 1900. Monograptus Nilssoni, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 432, text-fig. 24, pl. xxv, figs. 28a, 28s. Polypary several cm. in length, straight distally, but with graceful double oO curvature in the proximal portion; slender, never exceeding 1 mm. in breadth. Thece eight tonime in 10mm.; simple tubes with slight tendency to sigmoid curvature, about 2 mm. in length, four to five times as lone as wide, over- lapping about one-third their length, melination low; apertural margins normal, those of straight distal portion usually at right angles to the direction of the polypary. Description.—Vhe form of the polypary with its straight distal portion, concave middle portion, and convex proximal termination, 1s Fias. 241 a—c.—Monograptus Nilssoni (Barr.). Inghly characteristic. It 1s extremely slender at s ley the proximal end, measuring only *2 mm., and then ON [2/7 widens gradually and persistently till the maximum iy N . Ay breadth of 1 mm. is attained. Ml % | fy The sicula is small, but distinct; it has a length 4 HY \ 1 of about 1°5 mm., and the first theca arises near its ' rH y Vv apex, so that the apertural portion of the sicula \ ay {i alone forms the termination of the polypary. i a ‘ The thecee are simple straight tubes overlapping - | 9 the merest fraction of their length in the convex ; ; j proximal portion of the polypary; but with the v c beginning of the concave portion, a slight curvature a. Proximal end, showing © sicula. ele : s : o£ Figured Quart. Journ. Geol, Soc, Makes its appearance in the walls, and this is even vol. lvi, p. 482, fig. 24a. Mont- oat : eee ey ie mon ry : gomery Road, near Welshpool, better seen in the straight distal part. The aper- Lower Ludlow Shales. Coll. Wood. b. Thece of proximal portion of the polypary. Enlargement of part ‘the ave “t] sually le whi 1 irs bP PE XXXVIL fie Le of the concave portion usually le somewhat obliquely ec. Distal theca. Enlargement of part to the oeneral direction of the polvparyv. those of of Plate XXXVIL, fig. 1c. S p o (eliecniy, esis Ox tural margins are even and normal, but while those the straight distal part are approximately at right angles, though not invariably so. Affinities.—The nearest relation of Monog. Nilssoni is undoubtedly Cyrtog. Carruthersi of the Upper Wenlock Beds, fragments of which are indistinguishable from similar fragments of MM. Nilssoni when both are similarly preserved, the only distinguishing feature being the presence of branches in the Cyrtograptus form. Horizon and Locatities—Lower Ludlow Shales (zone of M. Nilssont). Lake District: Moughton Whetstone Hole, Crummackdale. Welsh Borders: Montgomery Road; River Irfon near Builth ; Vicarage Road, Builth; Old Dingle MONOGRAPTUS. 371 Mill, Long Mountain, etc. WN, Wales: Deeside Slab Quarries, Moel Ferna. Ludlow District: Elton Lane; Elton-Ludlow Road ; Adferton. Associates, ete. —Monog. Nilssoni is a very abundant fossil in the Lower Ludlow Shales, fragments of the distal straight portion, from 5—7 cm. in length, being of frequent occurrence at some localities ; specimens showing the graceful double curvature of the proximal region are much rarer. It usually occurs associated with Monog. colonus and var. compactus, M. bohemicus, M. varians and var. pumilus, M. Roemeri, M. dubius, M. uncinatus var. orbatus, and var. avieropome. Collections.—Sedewick Museum, Lapworth, the Authors, ete. I. A. 2: Monograpti in which the thece are uniform and the polypary is straight. Monograptus leptotheca, Lapworth. Plate XXXVII, figs. 2 «—i. 1876. Monograptus leptotheca, Lapworth, Geol. Mag., dec. 1, vol. ili, p. 352, pl. xu, figs. 4a —e. 1876. Monograptus leptotheca, Lapworth, Cat. West. Scott. Foss., pl. i, fig. 14. 1877. Monograptus leptotheca, Lapworth, Proc. Belfast Nat Field Club, p. 180, pl. v, fig. 22. 1882. Monograptus leptotheca, Tullberg, Graps. descr, by Hisinger, Bihang K. Vet. Akad. HundL., volewvi, p- 12) pl 1, figs; 8——l2. 1899. Monojraptus leptotheca, Tornquist, Monograptide of Scanian Rastrites Beds, Lunds Univ. Arssk., vol. xxxv, Dba 2 DOn ll apo: Polypary of very great but unknown length, approximately straight and staff, but with sheht curvature near proximal end; widening gradually and persistently till the maximum breadth of 35 mm. is attained. Thecee eight to ten in 10 mm., extremely long slender tubes, overlap considerable even in initial portion and reaching a maximum of fully three-quarters of the thecal length ; apertural margims even, approximately horizontal. Description.—Though the proximal portion is not well known, it is clear that the polypary itself must have been remarkably long, for fragmentary specimens exceeding 10 cm. in length are known in which the breadth is uniform throughout, while others 8 or 9 cm. in length are also known in which the maximum breadth is not attamed and in which the thecee are only about half as long as those of the more distal portions. In most specimens, indeed, the maximum breadth is never seen; these commonly show a width of about 2 mm. only. The mature thecz have a length of fully 8 mm., their walls tend to show sheht curvature, and there is a slight expansion in the apertural region; so extremely slender are they that on an average a horizontal line in any distal fragment would cut through four or five thece. Their overlap is always con- siderable, and increases throughout the leneth of the polypary until the maximum breadth is attained, after which it appears to be constant. 372 BRITISH GRAPTOLITES. Affinities.—The very long slender thecx with their great overlap are highly characteristic of this species, the only forms approaching it in this respect being Fias, 242 a—c.—Monograptus lepto. MM. acinaces and M. vegularis. In M. acinaces, how- esi Soros ever, the distal thecze are more trumpet-shaped and ity a the overlap is not so great, while in M. regularis J | Ag the overlap is also less and the proximal end of the \ Fie polypary is stiff and straight like the distal termi- i ih nation. ay \\ Tovizow and Localities. —Liandoyvery (Birkhill \ \ Shales), zones of M. gregarius to M. Sedgwickiti. { (\ S. Scotland: Dobb’s Linn; Beleraig Burn ; Frenchland Burn, ete. OC. Wales : Rhayader; Rhei- dol Gorge; River Twymyn. WN. Wales: Pary’s fi Mountain, Anglesea; Llanystwmdwy. Lake Dis- a b c trict: Skelgill; W. side Long Sleddale ; Stile End; a. Thece of the proximal portion of the : . { polypary, part preserved as a cast, Whinny Gill, Cross How Beck. yart in relief. Hnlargement of part eG : | pL XXXVI, fig. 2b. : I Associates, ete.—Monog. leptotheca seems to make b. More distal part of same specimen. c. Distal thece, preserved as a cast, figured Lapworth, Geol. Mae., 1876, foe) pl. xii, fig. 4.e. Dobb’s Linn ; Birk- PAM ehgvas, CO Way cod which itis very common. It is also fairly abundant its first appearance in the zone of M. gregarius about the horizon of the M. argenteus band, in in the zone of M. convolutus and survives into the zone of M. Sedqwickti. It is commonly associated with Monog. argenteus, var. cyqneus, M. gregarius and M. nillepeda at the lower horizon, with M. convolutus, M. involutus and M. harpago in the M. convolutus zone, and with M. tenuis and M. Sedgwichii in the zone of M. Sedqwickit. Collections.—Geological Surveys of England and Wales, and Scotland, Sedgewick Museum, Jones, Greenly, Lapworth, and the Authors. Monograptus regularis, Térnquist. Plate XXXVI, figs. 3 a—d. 1899. Monograptus regularis, Tornquist, Monograptidee of Scanian Rastrites Beds, Lunds Univ. 14. Arssk., vol. xxxv, pt. 2, no. 1, p. 7, pl. i, figs. 9 Polypary several cm. in Jength, straight and approximately rigid throughout, widening persistently from an initial breadth of about 3 mm. till the maximum width of 1°5 mm. is attained. Thece twelve to eight in 10 mm., simple tubes overlapping but shghtly in the proximal portion, but overlap increasing to two-thirds of total length distally ; apertural margins wide, even, shghtly everted. Descrviption.—The polypary is often very long, and the increase in breadth in the proximal portion is so gradual as to be scarcely perceptible. MONOGRAPTUS. 373 The sicula is small, not exceeding *7 mm. in length, and barely reaches to the level of the aperture of th. 1 which arises close to its base. Fias. 243 a—c.-—-Monograptus regularis, Térnquist. Yi hy 4 a | a ¥ v Ty — y 8 ~ mi ‘ 4 ce | iy rr a Vj ‘ yr j \ { i ra VA\} vei ¥ rh } 7A i ‘] rl : Aw h, x j a ed i y\) ya \ a AK } ‘ Ki UI At ANY i Wy =) a b c a, Proximal portion of the polypary, showing sicula. East side of old quarry, N.E. of Fagwr-fawr Farm, 2 miles E.N.E. of Pont Erwyd, Cardiganshire. Coll. Geol. Survey of England and Wales. b. More distal thee. Enlargement of part of Pl. XX XVII, fig. 3 a. c. Distal thece. Llanystwmdwy, near Criccieth ; Upper Llandovery beds. Coll. Fearnsides. The thecee of the proximal portion overlap very slightly and have their apertural margins approximately perpendicular to the general trend of the polypary; the overlap, however, increases steadily until in the distal portion the thecz over- lap fully two-thirds of their length; they narrow somewhat towards their apertural margins, which are slightly everted. The length of a mature theca is about 3°5 mm. Affinities.—In the general form of the polypary Monog. regularis comes fairly near to M. jaculwin, especially as regards the character of the proximal end ; but in M. jaculum the distal thecze never show so large an amount of overlap. As regards the characters of the distal theca: M. reqularis approaches M, leptotheca and might be confounded with it, but the overlap is never so great, nor are the thece so slender as in that species. Horizon and Localities—Llandovery (Birkhill Shales), zone of M. convolutus. Wales: Rheidol Gorge; River Twymyn, near S. Scot- Ireland: Near Llanbrynmair ; Pary’s Mt., Anglesea, etc. land: Dobb’s Limehill, Pomeroy. Linn; Beleraig. Associates, -etc.—Monog. regularis seems to occur most abundantly in the zone of M. convolutus, associated with M. convolutus, M. involutus, M. harpago, Cephalog. cometa, and other forms. uncertain. It is possible that it ranges even higher, but this is Collections.—Sedgwick Museum, Geological Surveys of Hngland and Wales, and Scotland, Jones, Greenly, Fearnsides, and the Authors. Monograptus jaculum (Lapworth). 1876. Plate XXXVIT, figs. 4 a—d. Monograptus Hisingeri, var. jaculum, Lapworth, Geol. Mag., dec. u1, vol. ii, p. 351, pl. xii, figs. 2a—d; and Cat. West. Scott. Foss., pl. i, fig. 13. 1877. fig. 20. 1899. 15—17. Monograptus Hisingeri, var. jaculum, Lapworth, Proc. Belfast Nat. Field Club, p. 130, pl. v, Monograptus jaculum, Tornquist, Lunds Univ. Arssk., vol. xxxv, pt. 2, no. 1, p. 7, pl. i, figs. Polypary often of great length, straight or with very shght curvature, slender BRITISH -GRAPTOLITES. OS. a | at origin but widening persistently to a maximum breadth of about 1°5 mm. Thece fourteen to nine in 10 mm., simple tubes, overlap insignificant in the proximal portion, but reachmg a maximum of about one-half the total length distally ; apertural margins wide and even, generally more or less horizontal. J , fo) ID e Description—The polypary may, and often does, attain a great length, but i e e J? 9 co) co) ? specimens with a length of only 3 or 4. em. are of commonest occurrence. The sicula is small, not exceeding *7 mm. in Fias. 244 a—d.—Monograpltus jaculum ' a : (Lapworth). length, but reaching fully to the level of the aper- ture of th. 1. The thecz in the proximal portion are very c \ os small and closely set, but become more distant ay \y | towards the distal extremity of the polypary. The ‘i Ml el 4 apertural margins tend to be more or less hori- Gi (\| WW ‘=| zontal, 1.e. perpendicular to the general trend of y y al “e| the polypary, and occupy about one-third of the wl \ N ae total breadth of it in profile view. The mature \ aN EI theca has a length of about 2°5 mm. v \ \ Ao Hace 4 a7 Peceiillcneles Wool Geol sare: the thecz and their overlap are much less in the of Scotland. > a 1r:71ea b. Proximal portion in relief. R. former a Yarrow ; Upper Birkhill Shales Horizon and Localities.—Llandovery (Birkhill (Band of Monograptus Halli). Coll. . 5 Pie ager eee Lapworth. Shales), zones of M. gregarius to M. Sedgwickii. ec. Distal thece in relief. Ibid. x1 ; ae. ; sir d. More distal thece, slightly com- S. Scotland: Dobb’s Linn; Beleraig Burn; pressed. Dobb’s Linn, Upper Birk- . : : 7 ; . hill Shales. Coll. Lapworth. Garple Linn; Lockerbie, etc. C. Wales: Rheidol Gorge, ete. N, Wales: Llanystwmdwy; Conway, ete. Ireland: Coalpit Bay, Donaghadee; Limehill, Co. Tyrone; Little River, Pomeroy, Co. Tyrone, ete. Lake District: Skelgill; Long Sleddale ; Tributary of Hall Gill, ete. Associates, ete.—Monog. jaculum is a very common fossil in the Upper Birkhill Shales of Moffat and their equivalents elsewhere. It occurs associated with Monog. gregarius, M. leptotheca, M. Clingani, M. communis, M. convolutus, M. harpago, M. involutus, M. Sedqwickii, Cephalog. cometa, and many other forms. Collections.—Sedgwick Museum, Geological Surveys of England and Wales, and of Scotland, Jones, Lapworth, and the Authors. Monograptus variabilis (Perner). Plate XXXVII, figs. 5 a, b. 1897. Monograptus jaculum, var. variabilis, Perner, Etudes sur les Grapt. de Bohéme, pt. iii, p. 12, jul sere tess 1K) Way MONOGRAPTUS. 379 Polypary some em. in length, straight or with slight tendency to curvature, increasing in breadth from an initial width of ‘4 mm. to a maximum of rather less than 1 mm. Thece twelve to eight in 10 mm., simple tubes shghtly expanded in the apertural region, with slght overlap; apertural margins even, horizontal, or slightly introverted. Description.—The polypary may attain a length of 5 cm. or more, but never exceeds 1 mm. in width and is usually rather less. me ee The sicula is small, measuring only 1°5 mm. in (Perner). length, but reaching well beyond the level of the wa aperture of th. 1. . The apertural margins of the earliest two thecz “4 appear to be slightly everted, but thereafter they are horizontal or even slightly introverted; the oy overlap may reach one-third of the total thecal eu! length as a maximum. f, le A Affinities.—The polypary presents some features 4 ler AY in common with both M. nudus and distal frag- i Wh Aa ments of M. Nilssoni. From MM. nudus its diminu- iy y q tive breadth should be sufficient to separate it ; and / i from M. Nilssoni it differs in the form of the poly- a b c pary, and also in the shape of the theca which shows a. Proximal end, showing sicula. En- largement of part of Pl. XX XVII, fig. 5 a. and introversi “the apertural oF -oach- b. More distal portion of same specimen. and introversion of the i er tura BERET et) ODORS c. Distal theew in low relief. Enlarge- jyno in these respects the form characteristic of the ment of part of Pl. XX XVII, fig. 5b. = l a greater tendency to curvature of the thecal walls croup of M. Sandersoni. Horizon and Localities—Gala-Tarannon Beds (zone of M. crispus). N. Wales : Conway. Associates, etc.—Monog. variabilis occurs in the zone of M. crispus associated with Monog. Mari and other forms. Collection.—Klles. Monograptus nudus (Lapworth). Plate XXXVII, figs. 6 a—e. 1876. Monograptus Hisingeri, Lapworth, Geoi. Mag., dec. ii, vol. iii, p. 350, pl. xii, figs. 1 a—e. 1880. Monograptus Hisingeri var. nudus, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p. 156, pl. iv, figs. 7 a—e. Polypary 83—5 em. in length, straight or with very sheht curvature, widening fairly rapidly to a maximum breadth of 2 mm. Thecx nine to ten in 10 mm., simple broad tubes, somewhat sacculate in the apertural region, overlapping one-half their length, and with even, wide, apertural margins. oO 376 BRITISH GRAPTOLITES. Description.—Vhe_ polypary of Monog. nudus is usually straight and rigid, resembling that of M. jaculum, but it does not exceed 5 cm. in length. The sicula is fully 1 mm. in length, and extends up to the aperture of th. 1, which originates near its base. The thece increase in length from 1°5 mm. proximally to 2 mm. distally, and the overlap increases from one-third to Fieas. 246 a—d.—Monograptus nudus (Lapworth). one-half. They are simple sacculate tubes, very broad in proportion to their length, with fy their free ventral margin somewhat impressed, /y producing a shght excavation. The average yy : J inclination of the thecz is high. ir ae |4 ff Affinities—-In the form of the polypary ly OF, —s es, Monog. nudus approaches M. jaculum, but 7 iy Ha | 47 differs in having shorter and broader thecz 7 Lif VAI ed with a ventral excavation. As respects the 4 ae Af thecee Monog. nudus approaches MM. concinnus, 4 4 v4 | fy but differs in having a straight polypary. iy ka” Ved, | ‘hy Horizon and Localities. — Llandovery — ‘Tarannon. si e : S. Scotland: Dobb’s Linn; Belcraig Burn ; a. Proximal end, showing sicula, in low relief. Enlargement of part of Pl. XXXVII, Grieston Quarry; Broadmeadows, Glendeare, fig. 6b. ee, ae b. Distal theew, in relief, showing ventral etc. Wales: Llanystwmdwy, near Criccieth ; excavation. Enlargement of part of : : : Pl. XXXVIL, fig. 6 d. Conway; Tarannon River; Llanbrynmair Rail- i. Distal ene me Shite tik way section, ete. 5 Pont Krwyd District. Ee art at eee aa a Associates, ete.— Monog. nudus is a character- istic Gala-Tarannon species; it is, however, occasionally found in the highest Llandovery beds. It occurs with Monog. Sedgqwickit and M. tenuis at the Llandovery horizon, and with M. turriculatus, M. exiqguus, M. discus, M. Marri, M. qriestonensis, and other forms in the Gala- Tarannon beds. It is fairly abundant. Collections.—Geological Survey of England and Wales, Lapworth and the Authors. Monograptus dubius (Suess). Plate XX XVII, figs. 7 a—d. 1850. — Graptolithus colonus, Barrande, Grapt. de Bohéme, p. 43, pl. ii, fig. 5. 1851. Graptolithus dubius, Suess, Ueber Bihmische Graptolithen, Haidinger’s Abhandl., vol. iv, pt. iv, p. 115, and pl. ix, figs. 5 a, 5 b. 1876. Monograptus dubius, Lapworth, Geol. Mag., dec. 11, vol. iii, p. 506, pl. xx, fig. 10. 1880. Monograptus serra, Hopkinson MS., Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, pl. iv, figs. 6e, d. 1883. Monograptus dubius, Tullberg, Skines Graptoliter, pt. 11, Sv. Geol. Undersékn, Ser. C, no. 09, p. 29, pl. i, figs. 28, 29, pl. ii, figs. 20, 21. MONOGRAPTUS. 370 1890. Monograptus dubius, Holm, Gotlands Graptoliter, Bihang till k. Svensk. Vet. Akad. Handl., vol. xvi, pt. iv, no. 7, p. 16, pl. i, figs. 18—26. 1893. Alonograptus dubius, Wiman, Bull. Geol. Inst. Upsala, vol. i, no. 2, p. 2, pl. vii. 1900. Monograptus dubius, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 454, pl. xxv, figs. 1 a, 1x, text-fig. 9. Polypary with a maximum length of 10 cm., straight distally, but with sheht ventral curvature in the proximal portion, widening gradually till maximum breadth of 2 mm. is attained. Thecz eleven to eight in 10 mm., fairly long and wide tubes two or three times as long as wide, overlapping from less than one-half to rather more than one-half their length; average QKO vo. inclination 30° Description.—Vhe polypary varies considerably in extent; at some horizons in the Wenlock Shales it rarely exceeds 4 cm. in length, and seldom attains the maximum breadth; whilst in the Lower Ludlow Pigs, 24/ a and b—Monograptus dubius Shales it is frequently 10 cm. long; in all other Suess.). respects, however, the examples from both forma- . / tions agree exactly. The shght ventral curvature Ma of the proximal portion in the neighbourhood of Vy ‘| the conspicuous sicula is highly characteristic ; it ae " rarely involves more than six thecze. 4 4 a 4 The sicula has a length of 1:7 mm. and is about : : LON fu xe ‘| | become simple parallel-sided tubes fay | SW 4 with 1 slightl ‘ted aper en . i. 4 with even and slightly everted aper- Aon y re “= . . 1 Seat! PD x tural margins. In the proximal thecze Ss @ am EH ; ote re the amount of overlap is very slight, a b on . . : a. Proximal portion of the polypary. Enlargement of part but this steadily aNeHeaces) Th amour of Pl. XXXVIIL, fig. 40. until distally it is fully one-half of b. Proximal portion of polypary, showing sicula ; doubtfully referable to this species. Enlargement of part of the entire leneth of the theca. Pl. XXXVIIL, fig. 4d. Affinities —Monog. difformis pre- sents some points of resemblance to M. revolutus and its variety precursor. It may, however, be readily separated from M. revolutus by the more robust character of the proximal end and the greater retroversion of the proximal thece ; from var. precursor, however, it differs mainly in the more robust character of the proximal portion of the polypary, the retroversion of the proximal thecz being very similar in the two forms. Horizon and Localities—Llandovery, Birkhill Shales (zone of Monog. gregarius). S. Scotland: Dobb’s Linn. C. Wales: Rheidol Gorge. N. Wales: Llany- stwmdwy. Associates, ete—Monogq. difformis apparently occurs in the lower part of the zone of MM. gregarius, associated with Monog. jfimbriatus and M. revolutus, var. austerus. It does not seem to be a common fossil. Vollections.—Jones, Fearnsides, Lapworth, and the Authors. 388 BRITISH GRAPTOLITES. Monograptus argenteus (Nicholson). Plate XXXVITI, figs. 5 a—d. 1869. Graptolites argenteus, Nicholson, Ann. Mag. Nat. Hist. [4], vol. iv, p. 239, pl. xi, fig. 19. Polypary 4—6 em. in length, with straight distal portion and abruptly recurved proximal portion; very slender at origin, widening gradually from a small and inconspicuous sicula to the bend, and thence very rapidly till the axl yreadth of 2°5 mm. is Fias. 257 a and b.—Monograptus argenteus (Nicholson). maximum breadth of 2°5 te attained. Thecz long narrow EL en tubes, fifteen to eleven in 10 mm.; EE — = Se . . . . al les ana in the proximal portion in contact a only, with tendency to complete oY) retroversion and isolation of the Ext)! : 5 \\!/ apertural region; overlap in- =e) j a creasing and apertural retro- l a A | . : . . LN version decreasing until finally ah Cc ; 3 © a the theese of the distal portion Cec. Gc te are simple tubes, overlapping ’ fully two-thirds their length, a. Proximal portion, showing sicula. Llanystwmdwy, with even apertural margins. near Criccieth ; Llandovery Beds. Coll. Fearnsides. Sate = ; b. Proximal portion of polypary, showing form of thece. Description.—Vhe poly pary 1 Monog. Ibid. argenteus 1s highly characteristic, with its slender straight proximal portion and the rapid change to the robust distal portion after the bend. The whole of the initial portion of the polypary, however, resembles that of M. limatulus in its extreme tenuity. The sicula is small and inconspicuous, barely Fias. 257 c and d.—Monograptus argenteus (Nicholson). reaching 1 mm. in length, and failing to reach the level of the aperture of th. 1. gy All the early theese are small and inconspicuous, WA] apart from the retroverted apertural extremity, Cea which appears somewhat lobate after compression. wy) The retroversion and isolation of the apertural Cd region of the thecz becomes at first more and more Mg e pronounced with remoteness from the sicula, and c. Proximal-distal thece, showing When the polypary has attained its maximum shange fr one type to the other. EnlarzementofpartofPLXXXVIIL, breadth the thece have the appearance of long fio. 5a. d. Distal theew, Partofsamespecimen, tubes with a distinct and isolate apertural hook. In the shorter specimens this character may be maintained, with some shortening of the hook, up to the distal termination, but in the longer and more complete specimens it is clear that the retroversion of MONOGRAPTUS. 389 the apertural region gradually diminishes, and finally the theew are simple tubes, with even and horizontal or slightly everted apertural margins. ‘I'he mature thecz are very slender and a horizontal line drawn across the polypary in its distal portion would cut four different thece. Affinities.—As M. limatulus, but distally it is a far larger and more robust species, and the thece respects its general form, Monog. argenteus approaches are different in form. Horizon and Localities —Llandovery (Skelgill Beds), sub-zone of M. argenteus. Lake District: Skelgall ; Criccieth. Mealy Gill, ete. N. Wales: Llanystwmdwy, near Associates, ete—Monogq. argenteus occurs in abundance in a definite band in the Stockdale Shales associated with Monog. leptotheca, M. gregarius, M. communis, Glyptog. sinuatus, ete.; and with similar associates at a corresponding horizon in N. Wales. Collections —British Museum (Natural History), Sedgwick Museum, Fearnsides, Marr, Lapworth, and the Authors. Var. cygneus (Tornquist). 1892. Plate XX XVIII, fi os. 6 a—d. . ° aiete 5 . € Monograptus cygneus, Tornquist, Lunds Univ. Arssk., vol. xxviii, p. 16, pl. i, figs. 28—31. While the typical Monog. argenteus has only as yet been recognised at Llanystwmdwy and in the Lake District, there occurs fairly abundantly im other Fias, 258 a and b.—Monograptus argen- teus, var. cygneus, Tornquist. Lins j / iP i ¥ fj - | Vg % | if P 4 / [= \o /4, } if’ fy A. a a my ce 4 / iP Lis i lel a b a. Proximal type of thee. Enlarge- ment of part of Pl. XXXVIL, fig. 6c. b. Distal type of thece. specimen, Part of same localities, both at the same horizon and ranging somewhat higher, a form which presents many points of resemblance to it, but is altogether narrower. ‘This seems to come very close to Torn- quist’s MM. cygneus, though, as originally described by him, his examples were shorter than is the case with many of our British specimens. In this form, which we consider best regarded as a variety of M. argenteus, the thecez, which are of the same general character as those of M. argenteus, are inclined at a lower angle, and are more distant (eight in 10 mm.) than those of the typical form ; the overlap does not exceed one-half the thecal length, and the polypary has an average breadth in the distal portion not exceeding 1°5 mm. The thread- like proximal portion is rather more than 1 cm. in length, and has precisely the same type of thece as has the typical species. 390 BRITISH GRAPTOLITES. Horizon and Localities —Llandovery (Birkhill Shales), sub-zone of AM. argenteus and zone of M. convolutus. S. Scotland: Dobb’s Linn, Belcraig Burn, ete. Lake District: Skelgill. C. Wales: Rheidol Gorge. N. Wales: Pary’s Mountain, Anglesea. Associates, ete.—Var. cygueus appears to be a commoner form than M. argenteus, and takes its place more or less completely in 8. Scotland. It is commonly found with Monog. leptotheca and M. concinius ; and in the Lake District it occurs with M. argenteus itself. Collections—Sedgwick Museum, Geological Survey of England and Wales, British Museum (Natural History), Greenly, Jones, and the Authors. Monograptus limatulus, Tornqust. Plate XXXVIII, figs. 7 a—d. 1892. Monograptus limatulus, 'Tornquist, Siljansomr. Grapt., Acta Univ. Lund., vol. xxviii, p. 9, pl. i, figs. 6—8. Tate GOs MONG ara pee Laine 1897. ? Monograptus limatulus, Perner, Etudes sur Tornquist. les Graptolites de Bohéme, pt. iii, sect. a, p. 10, pl. > ys aie oP kA 1899. Monograptus limatulus, Tornquist, Monograp- f % tide of Seanian Rastrites Beds, Lunds Univ. Arssk., vol. xxxv, pt. 2, no. 1, p. 14, pl. ii, figs. 18—20. y Polypary short, not exceeding 4 cm. in vi“ length, arcuate or straight distally, ~ stiffly and abruptly recurved in proxi- mal portion; very slender and thread- a hke at origin, but widening abruptly and rapidly at the bend to a maximum ee 4 breadth of about 1mm. Thecz twelve \ ewe L3 5 . A > F in 10 mm.; those of the proximal x4 portion in contact only, with slightly a curved walls and shghtly retroverted Se apertural margins ; those of the distal BIN portion simple tubes, overlapping one- “ie half their length, with even everted apertural margins. b Description—The form of the polypary a. Proximal portion of polypary, mainly preserved with its stiff and abrupt recurvature, and as a cast. Llanystwmdwy, near Criccieth ; j ‘ ‘ : Llandovery Beds. Coll. Fearnsides. slender proximal portion is highly character- b. Specimen, showing the proximal thece. Skel- |, : ; : : : gill; Stockdale Shales (zone of Monog. con- istic of this species; so slender, indeed, is volutus). Sedgwick Museum. ¢ : . c. Small proximal fragment in relief. Rheidol the polypary at its proximal extremity that Gorge, Cardiganshire. Geol. Survey of . : England and Wales. 1t sometimes appears to taper to a mere MONOGRAPTUS. a9] thread, in which in imperfectly preserved specimens it is almost impossible to detect the long, narrow thece ; these are nearly in contact, and so delicate for the greater part of their length that it almost appears as if the hooked apertural extremities were isolate from each other at considerable distances. There are commonly five or six thece of this proximal type; those of the more distal portion are simple tubes of the ordinary ‘‘ cyphus” type. Affinities —In the general characters of the proximal end M. liimatulus approaches M. argenteus very closely; it may, however, be readily distinguished by the smooth and even apertural margins of the more distal thecz and the lesser breadth of the polypary throughout the distal portion. Horizon and Localities—LUlandovery, Birkhill Shales (zones of M. convolutus and M. Sedgwichit). S. Scotland: Dobb’s Linn, Moffat; Beleraig Burn, Moffat, ete. Lake District: Skelgill. C. Wales: Quarry, N.E. Gwen-ffrwd Uchaf Farm, Pont Erwyd. N. Wales: Pary’s Mountain, Anglesea; Llanystwmdwy, near Criccieth. Ireland: Coalpit Bay, Donaghadee. Associates, ete.—M. limatulus occurs in some abundance in the zones of M. con- volutus and M. Sedgwickit; associated with the zone fossil, M. involutus, M. Clingana, M. harpago, and Cephalog. cometa, in the zone of M. convolutus, and with M. tenuis, Glyptog. serratus and Cl. scalaris in the zone of M. Sedgwickii; in the Lake District it occurs with J. argenteus in the sub-zone of M. argenteus, and in the Pont Krwyd country with M. leptotheca at the same horizon. It is only rarely found at any lower horizons. Collections—Geological Survey of England and Wales, Geological Survey of Scotland, Sedgwick Museum, Jones, Fearnsides, Lapworth, and the Authors, ete. I. B. 2: Monograptt in which the thece are bi-form and the polyparies are approximately straight. Monograptus colonus (Barrande). Plate XX XVIII, figs. 8 a—d. 1850. Graptolithus colonus, Barrande, Graptolites de Bohéme, p. 42, pl. ii, figs. 2, 3. 1852. =? Graptolithus colonus, Geinitz, Die Graptolithen . . . der Grauwackenformation in Sachsen, p- 38; pl. ii; figs. 38—36. 1880. Monograptus Remeri, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p. 151, pl. iv, figs. 5 a— de. 1883. Monograptus colonus, Tullberg, Skanes Graptoliter, pl. 1, figs. 22 and 23. 1890. Monograptus colonus, Geinitz, Die Graptolithen d. k. min. Mus. in Dresden, Mitth. d. k. Min. Geol.-Prihist. Mus. Dresden, pt. ix, pp. 15, 16, pl. a, fig. 14. 1892. Monograptus colonus, Barrois, Distribution des Graptolites en France, Ann. Soc. Géol. Nord, vol. xx, p. 100. 1897. = Pristiograptus colonus, Frech, Lethea Geognostica, vol. i, pt. ili, pp. 655, 656, fig. 209. 52 392 BRITISH GhAPTORUIES. 1899. Monograptus colonus, Perner, Etudes sur les Graptolites de Bohéme, pt. in, sect. b, p. 9; pl: xiv, figs. 3, 12, 17, text-fig. 12. 1900. Monograptus colonus, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 463, pl. xxv, figs. 10 a—p, text-fig. 14. Polypary 4—6 em. in length, distally straight, but with distinct ventral curvature proximally, widening gradually till the maximum breadth of 2°3 mm. is attained. Thece twelve to ten in 10 mm., those of the proximal portion with ogee curvature of walls and retroverted apertural extremities ; becoming simpler distally, and finally tubes of uniform width with a length of 3 mm., at least four times as long as wide, overlapping fully two-thirds of their length, and with an average inclination of 35° to 45°. Virgula occasionally prolonged distally. Description —The polypary has a characteristic form, the inward curvature of the proximal portion involving the first seven to ten thece. The increase in breadth is somewhat rapid at first and is then Fias. 260 a—c.—Monograptus colonus (Barrande). gradual until the maximum breadth is attained ; “=>, this is then maintained as a rule to the distal extre- Pe) i = ' N AP /*,| mity. The virgula may. occasionally be observed x / A 7 y 7 (=) : hs Sige jy extending for a short distance beyond the distal I “\ ? ri Fo. : 5 ‘ : bg /j/» extremity of the polypary. * A> he AS : j . lee 79 7 The sicula, though small (not exceeding 1°6 mm. oe Lh A in length), is usually conspicuous; it reaches to Regn SO ; Na y Jo the level of the apertural margin of the second \v | ee i yy ; theca. a b c The four proximal thecz show the ogee curva- a. Complete specimen preserved in re- liet, naturalsize. Figured, Quart. ture and the retroverted apertural extremities, but Journ. Geol. Soe., vol. lvi, pl. xxv, fig. 10. Butowitz, Bohemia. these features are most pronounced in th. 1 and Coll. Lapworth. 9 : ¢ b. Proximal end, showing sicula. th. 2, which are shorter and relatively much broader Figured, Quart. Journ. Geol. Soc., m vol. lvi, p. 464, fig. 14a. Vicarage than any subsequently developed. The mature ac h; jer Shales. Gis HG Spee . Hoad, Buin; Lower LudlowShales. theca are very similar to those characteristic of the * PRoad, Builth, Lower LudlowShales, Preceding group; they have an approximately uni- oe Coe form breadth, straight walls, and an even apertural margin usually devoid of a flange; the thecal length usually increases until it is fully four times the breadth, and may be more. Specimens from different British localities are apt to exlibit shght variations amongst themselves; these, however, appear to have only a local significance. The specimens from Helm Knot seem to come closest to the accepted Bohemian types ; others from Adferton (Ludlow District) appear to widen rather more rapidly and have mature thecee which are fully five times as long as broad; some from the Builth district resemble the Bohemian forms very closely, whilst others show more conspicuous proximal curvature and rather more closely set thecv (thirteen MONOGRAPTUS. 393 to twelve in 10 mm.), and the polypary as a whole is somewhat longer and narrower. Affinities—Many different species of Graptolites have been erroneously referred to Barrande’s species Monog. colonus ; of these the commonest were those later described by Wood as M. vulgaris, M. tumescens, and M. varians (loc. cit. supra). In all four species the distal theca resemble each other very closely, but the proximal thece and the general characters of the proximal end are different. From M. vulgaris, M. colonus differs in the curved proximal end and in the characters of the proximal thece, from M. tumescens in the characters of the proximal thecx, and from M. varians in its wider polypary and somewhat different distal thecz with their greater overlap. Horizon and Localities—Lower Ludlow Shales (zone of M. Nilsson‘). Lake District: Helm Knot, Dent; N.E. Casterton Fell. N. Wales: Deeside Slab Quarries, Moel Ferna; Hills N.E. Llanrwst; R. bank of Dee, Llangollen, etc. Welsh Borders: High Cliff, R. Irfon, near Builth; Vicarage Road, Builth, ete. Ludlow District: Elton Lane; Adferton ; Trippleton Lane; Bow Bridge, ete. Associates, etc.—Monog. colonus is a fairly abundant fossil in the Lower Ludlow Shales where the Mudstone facies is best developed, as it is in the Builth District ; elsewhere it is by no means so abundant as has generally been supposed, though it is essentially a characteristic fossil of the lower part of those shales. It occurs typically in the zone of M. Nilsson, and is usually to be found in association with the zone fossil, 47. bohemicus, MW. dubius, and Gothog. spinosus. Collections.—Sedgwick Museum, British Museum (Natural History), Hopkinson, Lapworth, and the Authors, ete. Var. compactus Wood. Plate XXXVIII, figs. 10 a—e. 1900. Monograptus colonus, var. compactus, Wood, Quart. Journ. Geol. Soce., vol. lvi, p. 466, pl. xxv, fig. 12. E26 I gg Monogr OPENS colonia Svar: A well-marked variety of MZ. colonus has been compactus, Wood. appropriately termed var. compactus. This agrees SE | with the typical Monog. colonus in the shape of the Sx thecee and character of the proximal extremity, but ¥ ae is distinguished from it (1) by its smaller size (not a exceeding 2°5 em. in length) and more decided | curvature; (2) by the densely set thecee (sixteen & to fourteen in 10 mm.), which may overlap as much SN oy as three-quarters of their length in the distal portion Yee ad of the polypary. The virgula is conspicuously Distal theew. HEnlargement of part of 6 Pl, XXXVIII, fig. 10a. ; prolonged beyond the distal end of the polypary. BRITISH GRAPTOLITES. —~ wo) I Horizon and Localities —Lower Ludlow Shales (zone of M. Nilssoni). Ludlow District: Elton-Evenhay Lane; Elton Lane; Stormer Hall. Associates, etec.—Var. compactus has up to the present time only been recorded with certainty from the Ludlow District; it may also, however, occur in the Abberley Hills, but this is uncertain. It was found in the zone of M. Nilssoni associated with the zone fossil, M. chimera var. Salweyi, and M. varians var. pumilus. Collections. Sedgwick Museum, Wood. Var. ludensis (Murchison). Plate XXXVIII, figs. 9 a—c. 1839. Graptolithus ludensis, Murchison, The Silurian System, pl. xxvi, fig. 2. 1879. ? Graptolithus ludensis, Quenstedt, Petrefactenkunde Deutschl., vol. vi, pp. 192—193, pl. cl, fig. 29. 1900. Monograptus colonus, var. ludensis, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 465, pl. xxv, oe e bo As has already been made clear by Wood (loc. cit. supra) there has been considerable misapprehension concerning this form ; the type specimen, now in the collection of the Geological Society of London, is badly preserved, and our f=) ? b personal collection and examination of material from Fig. 262.—Monograptus colonus, var. : F 3 ludensis (Murchison). the same locality as that from which Murchison Mie r# procured his original specimens have unfortunately not completely solved the problem. The specimens fa are all preserved in a hard calcareous sandstone Re cx ry which weathers deeply, and it is only on the weathered surface that the Graptolites can be seen. Wy As yet it has been impossible to determine with iataieey ge mae Enlarge. 8CCUTaCy whether the proximal thece really re- gabe part of Pl. XXXVI, semble those of Monog. colonus; one at any rate ae appears to show ogee curvature and retroverted apertural extremity, but whether or not there are more thece of this type is uncertain. The mature thece appear to be somewhat larger than those of J. colonus itself, being apparently quite six times as long as wide. For the present it seems best to retain Murchison’s name for the specimens from Llanfair, and to regard them as constituting a variety of M. colonus. It might, perhaps, be urged that if MW. ludensis and M. colonus probably belong to the same species, the older name —WM. ludensis—should be applied to both. But Barrande’s name—WM. colonus —has been classic in paleontological literature for the last half century and more, and has obtained such acceptance among Graptolithologists in general that the change would be pedantic. Horizon and Locality.—Lower Ludlow (?). (Je) io) (ed) ¢ MONOGRAPTUS. Wales: Llanfair, Montgomeryshire. Associates, ete.—It has been a little difficult to determine the horizon of var. ludensis, but it is almost certainly a Lower Ludlow form; M. dubius is its only associate. Collections.—Geological Society of London; Dr. Humphreys (Llanfair), Wood. Monograptus varians, Wood. Plate XXXIX, figs. 6a—e. 1880. Monograptus colonus, Lapworth, Aun. Mag. Nat. Hist. [5], vol. v, p. 152, pl. iv, figs. 3b—3 d. 1900. Monograptus varians, Wood, Quart. Journ. Geol. Soc., p. 467, text-fig. 15, pl. xxv, figs. 14.4 and 148, 15, 164 and 16 zB. Polypary from 2—2°5 em. in length, straight with shght ventral curvature near the proximal end, width increasing throughout to a maximum breadth of about 2 mm. or rather less. Thecze Fras. 268 a—e.—Monograptus varians, sl . Wood. fourteen to ten in 10 mm., typically three at i the proximal end show retroverted apertural ) extremities, those of maturer portion of the y : polypary simple tubes with very wide aper- g ! tural margins, 2 mm. in length, from two to three times as long as wide, overlapping A one-half their length, and with an average Wil s inclination of 30° to 40° Vireula con- oN fs spicuous. wv} i Description.—The polypary in Monog. varians is “yi Ib > always short, never apparently exceeding 2°5 em. in Y i oy length and generally being only about 2 em.; the increase in breadth takes place fairly rapidly in the proximal portion, and thence is more gradually slab as Pl. XX XIX, fig. 6a. 5 p : 5 b. Proximal end. Figured, Quart. continued right up to the distal extremity. The Journ, Geol. Soc., vol. vi, p. 467, + Fi fic. 156. Road above Garbett, Wirgula is generally very conspicuous at the distal Hall, Long Mountain; Lower Lud- 2 : Nas low Shales. Coll. Wood. end of the polypary. gage eerol youd; Showing) Nang uls: and The sicula has a length of about 2 mm. and is character of thece. Enlargement 5 of reverse side of part of Pl. Jono relatively to its breadth, reaching well above XXXIX, fig. 6a. 5 Y , 5 ENONIC b c a. Sicula and th. 1. Specimen on same the level of the second thecal aperture. The ogee form of the proximal thecw is not nearly so conspicuous as in M. colonus, though there are distinct traces of it in th. 1; all the earhest three thecee may have retroverted apertural extremities, though this feature is some- times not discernible in th. 3. In the theca developed later the great width of the apertural margin is often associated with a distinct compression of the ventral wall of the theca next above, resulting in a most characteristic appearance. In 396 BRITISH GRAPTOLITES. the proximal portion of the polypary the thecz are barely twice as long as wide, but the length increases in the distal portion. Affinities —At first sight this form appears to resemble M. colonus very closely ; the polypary, however, is in reality shorter and narrower, it increases more uniformly in breadth throughout its length, and the characters of the adult theca are different. Horizon and Localities.—Lower Ludlow Shales (zone of M. Nilssont). Long Mountain District : Winnington Green; Old Dingle Mill; Garbett’s Hall ; Trefnant-Middletown Brook. Ludlow District: Mary Knoll; Elton Lane. Associates, etc.—Monog. varians seems to take the place of M. colonus in the Lower Ludlow Shales of the Long Mountain District, where it occurs in some abundance associated with Monog. Nilssoni, M. dubius, and M. varians var. pumilus ; it also occurs, though rather less commonly, in the Ludlow District at the same horizon, associated with M. Nilssoni, M. chimera var. Salweyi, and M. dubius. Collections.—Sedewick Museum, Hopkinson, Lapworth, and the Authors. Note.—Monoq. varians is remarkable in presenting certain local variations, and on approximately the same horizon, so far as can be judged. It occurs at several localities in large numbers in the Long Mountain District; at some of these it is small, and only the two basal thecs are retroverted at their apertures. At Dingle Mill its length is normal, but so far as can be seen only one theca shows a retroverted aperture; while at Garbett’s Hall it is still long but with two Fras. 264 a—e-—Monograptus varians, basal thecee showing the retroverted character. eee ee Again, in the Trefnant-Middletown Brook it is a somewhat broader than usual, and the first three , po» theese are all retrovert. In all cases the fossils ‘/<_ seem to occur in association with M. Nilsson. , ‘ee The description as given above includes Wood’s “var. a and var. B, which are probably inconstant in local varieties. OSes (ee “Var. pumilus, Wood. Plate XXXIX, fi ia 2 2 iy \ My \F 1900. = Monograptus varians, var. pumilus, Wood, Quart. Journ. cA. 4 ae . é . mM aed v Geol. Soc., vol. lvi, p. 469, text-fig. 16, pl. xxv, figs. 17 a, 17 B. a b Cc a. Proximal end, showing sicula. Elton Lane, Ludlow; Lower Ludlow Shales.’ “Coll: Woods) | variation in the species M. rarians, there is one form b. Distal thece. Abberley Hills; Lower Be OW eee ac ounce nan which, having a longer range than the typical ing. ‘ ; : : c. Complete specimen, showing sicula species and other more definite characters, seems and thecal growth lines, preserved ee , ; asacast. Figured in part, Quart. worthy of distinction, and has been described by Journ. Geol. Soc., vol. lvi, p. 469 == i sae 4 a , fig. 16c. Round Hill, Abberley; Wood as var. punulus. This variety is mvariably Lower Ludlow Shales. Coll. Wick- . ° 5 9 a5. ham King. small in size, rarely exceeding 1:2 cm. in length, While allowing for a certain amount of local MONOGRAPTUS. 397 the proximal curvature is very slight, the sicula extends to nearly the level of the aperture of th. 3, and the thece are very closely set (sixteen to fourteen in 10 mm.). Horizon and Localities—Lower Ludlow Shales (zones of M. Nilssoui and M. scanicus). Iudlow District: Elton Lane ; Elton-Evenhay Lane; Stormer Hall; Abberley Hills. Associates, ete.—Var. pumilus has a very characteristic gregarious habit, often occurring in dense crowds on slabs of rock almost to the exclusion of any other form. It occurs in the zone of M. Nilssoni associated with the zone fossil, M. colonus var. compactus, M. dubius, and M. varians; and in the zone of M. scanicus with M. scanicus, M. chimera, and M. chimera var. Salweyt. Collections.—Sedewick Museum, Wickham King, and the Authors. Monograptus Roemeri (Barrande). Plate XXXIX, figs. 2 w—d. 1850. Graptolithus Remeri, Barrande, Graptolites de Bohéme, p. 41, pl. ii, figs. 9—11. 1869. Monograptus Remeri, Heidenhain, Zeitschr. d. deutsch. geol. Gesellsch., vol. xxi, p. 150, pled, tgs oO. 1879. Graptolithus colonus, Quenstedt, Petrefactenkunde Deutschl., vol. vi, pl. cl, fig. 40. 1883. ? Monograptus colonus, Tullberg, Skines Graptoliter, pl. i, fig. 21. 1884. Monograptus Remeri, J. D. La Vouche, Handbook to the Geology of Shropshire, p. 78, pl. xvii, fig. 578. 1897. Pristiograptus Remeri, Frech, Lethea Geognostica, pt. 11, p. 656, fig. 210. 1899. Monograplus Remeri, Perner, Etudes sur les Graptolites de Boheme, pt. 11, sect. b, p. 8, pl. xiv, figs. 1, 7, 10, 18, 24, text-fig. 11. 1900. Monograptus Remeri, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 470, text-fig. 17, pl. xxv, figs. 13a, 13s. Polypary 3—8 em. in length, with slight ventral curvature proximally and sheht dorsal curvature distally, increasing rapidly in width at first and then more gradually till the maximum breadth of about 3 mim. is attained. Thecv sixteen to eleven in 10 mm.; two proximal ones with retroverted apertural extremity; the rest approximately straight-walled simple tubes increasing in length distally till they measure 4+ mm. or more in length, five or five and a half times as long as wide, overlapping fully two-thirds their length, and having an average inclination of 40° to 45°. Description.—The form of the polypary of Monog. Roemert with its slight double curvature is highly characteristic, as is also its rapid increase in width im the proximal portion. The sicula has a length of about 1°38 mm., and it extends well above the apertural margin of the second theca. 398 BRITISH GRAPTOLITES. The thee are also markedly characteristic of the species, only two show traces of ogee curvature and retroversion of the apertural extremity, in neither case very pronounced. The great length of the theez in Fias. 265 a and b.—Monograptus ; : : ; Roemeri (Barrande). proportion to their breadth in the mature portion k of the polypary is most noticeable, as is also their t high angle of inclination and amount. of overlap. | There is occasionally a tendency to diminish in | Fs breadth in the distal portion of the polypary, but Ff. d this may only signify immature development of the Vy thece. Ce 4 Affinities. —Monog. Roemertis undoubtedly closely . Fh, related to M. colonus, but it can be easily separated : Za from that species by the greater length of the é. . | fy y mature thece. el j*#) Horizon and Localities—Lower Ludlow Shales | hy (zones of M. Nilssoni and M. scanicus) and their : 1) | jp» equivalents. aie Ludlow District: Elton Lane; Elton-Ludlow a b Road. Long Mountain District: Trefnant-Middle- . Proximal end, s ing sicula. En- ; ee : a BY oe Che ee vee pat of town Brook. Lake District: Helm Knot, Dent. arg s b. Didal thee inci? Helm Knot, Staffs.: Dudley, Walsall. Welsh Borders : Aberedw Dent; Coniston Grits. Sedgwick Hill, Builth. Museum. 4 : 0 Associates, etc.—Monog. Roemeri is not a common fossil in British rocks; it occurs, however, in the zone of M. Nilssoni associated with the zone fossil and AM. colonus, and at a ligher horizon with M. scanicus and M. chimera. Vollections.— Sedgwick Museum, Uniy. of Birmingham, Lapworth, and Wood. Monograptus chimera (Barrande). Plate XX XIX, figs. 3 a—d. 1850. = Graptolithus chimera, Barrande, Graptolites de Boheme, p. 52, pl. iv, figs. 34, 35. 1889. Pristiograptus colonus, Jackel (?), Zeitschr. d. deutsch. geol. Gesellsch., vol. xli, p. 674, pl. xxvill, fig. 8. 1899. Monograptus chimera, Perner, Etudes sur les Graptolites de Bohéme, pt. iii, sect. b, p. 14, pl. xvii, figs. 15 a, b. 1900. Monograptus chimera, Wood, Quart. Journ, Geol. Soe., vol. lvi, p. 471, pl. xxv, figs. 18 a—p. Polypary 2—4: em. in length, straight distally, but with slight ventral curvature in the proximal portion, increasing rapidly in width at first and then more gradually till the maximum breadth of 2 mm. is attained. Thece thirteen to eleven in 10 mm., appearing as somewhat hexagonal prisms with spined MONOGRAPTUS. 399 apertural margin, having a length of 2 mm., four times as long as wide, and overlapping one-half their extent ; average inclination high—40°-50°. Deseviption.—In the general form and characters of the polypary as a whole apart from the spines, Monog. chimera is somewhat like M. colonus, but it is typically shorter and broader. The thecz are very distinctive and present different appearances according to the direction and amount of compression. When the thece are shown in profile the spine has a curious position, originating, as it were, from the angle of a cusp Pe Seale Ar eciay ines situated in the middle of the apertural margin (Barrande). (Fig. 266 a). In other cases, however, in which the thecee seem to narrow somewhat in the apertural region, the spine appears to be in a more usual position, and to come off where the ventral wall meets the apertural edge. The spines of the proximal thecze appear to be always in this latter Su position, and it is possible that these theca, which < Px certainly show signs of ogee curvature of their ‘ail walls and retroversion of their thecal apertures, are tg different in shape from those of the more distal a. xy portions of the polypary. The appearance of the “a! mature thece suggests that they were more or less | hexagonal in section; indeed, in one specimen, preserved so that the apertures face the observer, a. Complete specimen, profile view; in one or two of the thecz are definitely hexagonal relief. Walsall, Staffs; Lower : ss = 5 4 : Ludlow Shales. Coll. Lapworth. (Fig. 2660). The apparent anomalies in the posi- b. Specimen, sub-ventral view, showing ; i : . form of thecal apertures, Elton tion of the spines would thus be explained by their ewer coming off from one of the angles made by the walls of the hexagonal prism with the apertural margin. The various positions assumed by the spines under different conditions of preservation may be seen from the figures. The spines are commonly stout and do not exceed *6 mm. in length. The sicula has a length of nearly 2 mm., and extends to midway between the apertures of th. 2 and th. 3. Affinities —The spined character of the thecze separates Monog. chimera from all other forms of the M. colonus group except its own variety Salweyi and M. leintwardinensis. From the former of these it may be readily distinguished by its shorter, stouter spines, and longer and more curved polypary. In J. leintwardinensis the spines are mesial in position and not apertural, except in the proximal portion, where the thecz agree closely in form with those of M. chimera. Horizon and Localities—Lower Ludlow Shales (zones of M. Nilssont and M. scanicus). 400 Ludlow District: Klton-Ludlow Road; Elton Lane. Welsh Borders: Aberedw Hill, Builth; Ucheldre Stream, Long Nest, Dudley. Mountain. BRITISH GRAPTOLITES. Staffs.: Walsall; Wren’s Associates.—Monog. chimera occurs typically in the zone of M. scanicus, associated with the zone fossil and M. Roemeri, but it is also found at a somewhat lower horizon with M. Nilssoni, M. bohemicus, and M. dubius. abundant fossil. It is not a very Collections. —Lapworth, University of Birmingham, Wood. Var. Salweyi (Hopkinson MS.). 1880. 1884. pl. xviii, fig. 571. 1900. 18, pl. xxv, figs. 19 4, B. Plate XX XIX, figs. 5 a—d. Monograptus Salweyi, Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p. 150, pl. iv, figs. 2 a—b. Monograptus chimera, J. D. La Touche, Handbook to the Geology of Shropshire, p. 77, Monograptus chimera, var. Salweyi, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 472, text-fig. Monog. chimera var. Salweyi was originally named by Hopkinson as a distinct Frias. 267 a and b.—Monograptus chim- wra, var, Salweyi (Hopkinson). | | wi ¢ ‘ x | bay oy hee se i es tse ‘ey He 1 Ady 14% 7 i: ade, = ioe ghd any hes, — |? gt j %, a7 al a Y f on Ly a a en { id y ; Vy ' a b a, Complete specimen, showing sicula. Ficured Quart. Journ. Geol. Soc., vol. lvi, p. 473, fig. 18a. Stormer Hall, nr. Leintwardine; Lower Ludlow Shales. Coll. Wood. b. Distal thee», showing thecal spines. Ibid., fig. 18 b. wardine ; Elton-Evenhay Lane. species, and lis type specimen, which shows only the distal extremity, was figured by Lapworth. As Wood, however, has already shown (loc. cit. supra), the collection of more material from the type locality has revealed the close connection be- tween this form and M. chimera, and it is best regarded as a variety of the species last described. Var. Salweyi differs from M. chimera itself in— (1) Its smaller size—it appears rarely to exceed 1:3 the straighter character of the proximal end; (3) cm. in length and 1:6 mm. in breadth; (2) the longer, slender, and more flexed thecal spines, which may be fully 1 mm. in length. The virgula is usually a conspicuous feature at the distal end of the polypary. Horizon and Localities—Lower Ludlow Shales (zone of M. Nilsson‘). Iudlow District : Long Mountain: Lettygynfach. Stormer Hall, near Leint- Collections.—Hopkinson, Wood. MONOGRAPTUS. 401 Var. semispinosus, nom. nov. Plate XXXIX, figs. 4 a—e. 1900. MM. chimera var. a, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 473, pl. xxv, fig. 20. This variety bears precisely the same relation to M. chimera that var. incipiens does to M. leintwardinensis ; it differs from M. chimera in being somewhat broader (2°5 mm.), and above all in having the distal theese devoid of spines altogether, while the proximal thece are spined in the usual manner. Horizon and Localities—Lower Ludlow Shales (zone of M. scaiicus). Tudlow District: Elton Lane; Elton-Ludlow Road. Var. semispinosus is only found in the zone of M. scanicus, where it occurs in association with the zone fossil and M. varians var. pumilus. Collections.—Lapworth and Wood. Monograptus leintwardinensis, Hopkinson MS. Plate XXXIX, figs. 8 a—f. 1880. Monograptus leintwardinensis, Hopkinson (MS.), Lapworth, Ann. Mag. Nat. Hist. [5], vol. v, p- 149, pl. iv, fig. 1. 1884. Monograptus leintwardinensis, J. D. La Touche, Handbook to the Geology of Shropshire, p- 77, pl. xviii, fig. 574. 1897. Pristiograptus uncinatus, Frech, Lethea Geognostica, pt. ili, p. 658, fig. 213. 1900. Monograptus leintwardinensis, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 474, text-fig. 19, pl. xxv, figs. 21 a, B. ; Polypary short, seldom exceeding 1°35 cm. in Frias. 268 a—c.— Monograptus leintwardi- nensis, Hopkinson. length, straight distally, but with slight hs curvature in the proximal portion, increasing Bs yet gradually in width until the maximum 4N| ) 4m breadth of 1:°6 mm. is attamed. Thece ony aN a spined, fourteen to fifteen in 10 mm.; those a j Gg ie ee of the distal portion fairly short tubes with AN / oh Zi. a length of about 2 mm., and about three i) y 8 times as long as wide, overlapping one-half Wi i Vo to two-thirds their length; those of the de : is proximal portion with slight ogee curvature a. Complete specimen, showing sicula. and retroverted and spined apertural margins. SARE fe 8 pee ate ee Zate Description—The polypary is always short and b. Complete specimen, showing various arrow: 7 7 yp > > 7 > ox ROLMOnE Of theediicpied Mieieed | anos At widens gradually for the first five or six Quart. Journ. Geol. Soe., vol. lvi, theese and has the al its J a p. 474 fig. 19. Church Hill eee tas len attamed its rao breadth, Quarry, Leintwardine ; Lower Lud- which is maintained to the distal extremity. low Shales. Coll. Lapworth. : 3 : A : c. Distal thece, showing paired spines. The sicula is long and conspicuous; it measures On same slab as Plate XXXIX, 9 A : : ee Lower Ludlow Shales, 2'1 mm. in length, extending to midway between oll, Hearnsides. the apertures of th. 2 and th. 3. 4.02 BRITISH GRAPTOLITES. The theex of the extreme proximal portion show a tendency to ogee curvature in their walls and appear to have retroverted and spined apertural margins. The spines of the mature distal thecee seem to be mesial in position, but this is possibly deceptive and due to compression, as their apparent point of origin is by no means constant in different individuals. Although in most cases only one spine is visible on each theca, yet it would appear from certain specimens (fig. 268 ¢) that a pair of spines is really present. Affinities.—Monogq. leintwardinensis is a most characteristic species, which, how- ever, is closely allied to M. chimera and its varieties; the proximal thece are certainly similar, but the spies of the distal thecz, so far as can be deter- mined, appear to be different in position. Horizon and Localities—Ludlow Shales (Aymestry Limestone), zone of M. leintwardinensis. Ludlow District: Church Hill, Leintwardine; Adferton ; Trippleton; Aymestry ; Vinnall; Ludlow Road; Broxton and Burton. Welsh Borders: Lettygynfach, Long Mountain; Aberedw, near Builth; Presteign, Old Radnor; Launwell Dingle. Lake District: Near Knock, ete. Dee Valley: Pen-y-vivod; Llantisilio Road. Collections—Sedgwick Museum, Fearnsides, Lapworth, and the Authors, ete. Var. incipiens, Wood. Plate XXXIX, figs. 9 a—d. 1900. Monograptus leintwardinensis, var. incipiens, Wood, Quart. Journ. Geol. Soc., vol. lvi, p. 474, pl. xxv, figs. 22 a, B. F146. 269.—Monograptus leintwardinensis, This variety Mono tntivardinensis agrees FL eens WG This variety of Monog. leintwardinensis agrees with the typical form in general, except that it 1s somewhat broader (2—2'3 mm.) and longer, and that only its proximal thece are spined. It bears the same relation to the typical form that var. semispinosus does to M. chimera. It has never been found, hitherto, in association with the typical form, and may be merely a local variant. Horizon and Localities —Lower Ludlow Shales (near summit). Welsh Borders: Montgomery Road; Rose and Ge ing anata aes 3 Crown Inn, Long Mountain; Lower Winnington, Montgomery Road; Lower Ludlow ete. Lake District: Tebay Gill, Bannisdale. Shales. Coll. Wood. Associates.—Var. inciplens seems to occur at a rather lower horizon than the typical M. leintwardinensis; its only known associate is M. cf. ultimus. Collection.—W atts, Wood. MONOGRAPTUS. 403 Group II. Monograptt in which the mature thece are tubes with flowing sigmoid curvature and oblique apertural margins. The Graptolites included in this group vary a good deal in the amount of sigmoid curvature of their thecal walls. Most of the species typically possess thecz resembling those of Leplograptus ; but the group includes at the one extreme M. atavus, a form in which the thecz are not very much curved, and at the other extreme M. argutus, in which the thece have marked curvature and both introversion and introtorsion of the apertural margin, characters approxi- mating to those typical of the Dicellograpti. The group includes the following species: Monograptus atuvus, M. Sandersont, M. incommodus, M. tenuis, M. argutus. Monograptus atavus, Jones. Plate XXXIX, figs. 1 a—d. 1909. Monograptus atavus, Jones, Quart. Journ. Geol. Soc., vol. lvi, p. 531, figs. 18 a—d. Polypary very long and slender, with shght dorsal curvature proximally, but sometimes shehtly ventral in its distal portion, widening gradually from an almost thread-lke proximal extremity to a maximum breadth of 1:2 mm. Thece nine to eight in 10 mm., simple tubes with varying amount of sigmoid curvature and slight introversion of the apertural margin, which, however, diminishes distally; overlap never exceeding one-half the thecal length. Description. —Monog. atavus must have attained a very great length, probably fully 50 cm. or more. The widening is almost imperceptible in the proximal portion, but the greater number of distal fragments have a uniform breadth, so that the maximum width must have been attained at a comparatively early stage. The sicula is but rarely seen; it seems to have a length of nearly 2 mm. and to form the proximal termination of the polypary ; it does not reach to the level of the aperture of th. 1. The thecv are relatively rather short (1°5—2°5 mm. in length), and are of the general type of those of the Leptograptide; the sigmoid curvature of the walls is constant, but appears to vary somewhat im amount in different specimens (compare Figs. 270 ¢ and 270 e). The distinct introversion of the apertural margin of the proximal thecz disappears distally, when the thecal margins may be even slightly everted. The number of thece per centimetre is fairly constant throughout the length of an individual, the overlap increasing with the general increase in length of the theca. LO: BRITISH GRAPTOLITES. Affinities. —Monog. atavus comes, perhaps, closest to MM. tenuis, Portlock, with which species it was confounded until recently. The thee of Monog. atavus are, Frias. 270 a—e.—Monograptus atavus, Jones. however, shorter and more closely set, and also inclined at a higher angle ; the apertural 7 / margins, too, are even and devoid of the | , f denticles or rostels frequently found in JM. | \ \\ -P fenwis. Monog. atavus also shows some re- } \ hy semblance to M. argutus; but the thecal f i N ih walls are less curved, and the apertural f \ \ i margins are not introtorted. | \ \ i] Horizon and Localities. — Llandovery " \ NI te ‘ad (Birkhill Shales), zones of Orthog. vesiculosus, a. Erocael rata mee sicula almost M. cyphus and AM. gregarins. ; LE ae te aaa cal S. Scotland : Dobb’s Linn; Belcraig Burn. Jones. Ireland: Coalpit Bay, Donaghadee; Mill b. Proximal portion, showing part of sicula. Ibid. ‘ c. Proximal portion in relief, showing sinuous Sluice below Slate Quarry, Pomeroy. Lake character of thece. Figured, Quart. Journ. aA A ‘ A : : = Geol. Soc., vol. Ixv, p. 533, fig. 18b. Rheidol District: Skelgill; Spengill. Wales : Rhay- Gorge. Coll. Geol. Survey of England and : Wales (No. 23710). * ader; Rheidol Gorge, Pont Erwyd; Pary’s i. More distal thece; part in relief, part cast. : Sey : : Mountain, Anglesea; Llanystwmdwy. Sara aaa Re ly oe ae dat} eg aa aa ha a Associates, ete.—Monog. atavus is the first Monograptus to make its appearance in geological time. In 8. Scotland it appears considerably below the base of the M. cyphus zone in the zone of Orthog. vesiculosus, and ranges up into the zone of M. cyphus associated with M. cyphus, M. Sandersoni, and various Dimorphograptt; at Skelgill it is found in the Dimorphograptus band ; in the Pont Hrwyd district also it appears im a band by itself before the coming in of M. cyphus. In the succeeding zone of M. gregarius it is not so abundant, but is found associated with M. fimbriatus, M. gregarius, and other forms. Collections.—Geological Survey of England and Wales, Sedgwick Museum, H. Lapworth, Jones, Lapworth, and the Authors. Monograptus Sandersoni, Lapworth. Plate XXXIX, figs. 10 a—e. 1876. Monograptus Sandersoni, Lapworth, Geol. Mag., dec. ii, vol. 111, p. 320, pl. x1, fig. 2 a—e. Polypary slender, of great length, with distinct ventral curvature proximally, and becoming straighter distally; widening almost imperceptibly from a thread-like proximal portion to a maximum of about *7 mm. Theczv eight to six in 10 mm., very long and narrow, inclined at so low an angle that their inner walls form an almost continuous line running parallel to the axis of the polypary, overlapping one-half their length, and with distinctly introverted apertural margins. MONOGRAPTUS. 405 Description.—The polypary is always slender, and shows ventral curvature especially in the proximal portion, in which it is very pronounced in some individuals (see Plate XXXIX, fig. 100). Distally the amount of curvature tends to decrease as a general rule, and fraements appear practically straight. Owing to the extreme tenuity of the proximal end it is difficult to find the Frias. 271 a—d.—Monograptus Sander- soni, Lapworth. ' \\ : i ( { fh) i } ‘| if ny i) | i) yi) iy i i i ¥) \ i \'y | i i My | | ! 4 | Hh) Mi : | (J a b c d a, Proximal portion, showing the sicula in part. Onsameslabas Pl. XX XIX, fig. 10. b. Proximal thece, showing various views of apertural margins. Dobb’s Linn; Birkhill Shales. Coll. Lap- worth. ec. Distal theee, showing introverted apertural margins. E. bank of road from Pont Erwyd to Devil’s Bridge; Castell Group. Geol. Survey of England and Wales. d. Distal theee, slightly different view. Enlargement of part of reverse of specimen figured on Plate XX XIX, tig. 10 e. sicula preserved, but it appears to be at least 1°6 min. in length, and to form the proximal termina- tion of the polypary (Fig. 271 a). The thecz are characteristic; they resemble very closely those regarded as typical of the genus Leptograptus, with sigmoid curvature of their walls and introversion of the apertural margins; they are commonly 2°5 mm. in length, and overlap one- half their length as a maximum. Affinities —In the characters of the thece and general tenuity of the polypary Monog. Sandersoni approaches M. incommodus, but differs markedly in the curvature of the polypary. The two species may readily be distinguished except in small distal frag- ments, which are very similar. Horizon and Localities. — Llandovery (Birkhill Shales), especially zone of M. cyphus. S. Scotland : Waterfall, Long Linn, Dobb’s Linn ; Frenchland Burn; Belcraig Burn, ete. Lake District: Skelgill, ete. Ireland: Coalpit Bay, Donaghadee. Wales: Kast bank of road, 50 yds. E.N.E. of Bryn- chwith Farm House, Pont Erwyd; Rheidol Gorge, 400 yds. H.S.H. of same, Pont Erwyd, ete. Associates, etc.—Monog. Sandersont occurs in Scotland in some abundance in the zone of J/. cyphus, associated with M. cyphus, M. revolutus, M. atavus, M. incommodus, Dimorphog. physophora, Climacog. medius and other forms. It occurs on a similar horizon in the Lake District in the Dimorphog. confertus band associated with M. incommedus and M. atavus; and also in Central Wales and Ireland. In8. Scotland, Ireland and C. Wales it also ranges up into the lower beds of the succeeding zone of M. gregarius, where it is associated with M. fimbriatus, M. gregavius, M. triangulatus var., Climacog. Tornquisti and other forms. Collections —Geological Survey of Hngland and Wales, Sedgwick Museum, Lapworth, Jones, and the Authors. 406 Monograptus incommodus, ‘l'érnquist. 1899. BRITISH GRAPTOLITES. Plate XL, figs. 1 a—e. Monograptus incommodus, Tornquist, Monograptide of Scanian Rastrites Beds Lunds Univ. Arssk., vol. xxxv, pt. 2, no: 1, p. 11, pl. ii, figs. 1—5. Polypary long and slender, with irregular curvature, widening from a slender, shghtly arcuate, or straight proximal portion to a flexed distal portion with an average breadth of ‘6 mm. Thece eight to seven in 10 mm., inclined at a very low angle and overlapping one-third to one-half their length ; apertural margins even and slightly introverted. Fias. 272 a—e.—Monograptus incommo- dus, Térnquist. 1) bal \j 4 Ary \4 Ay 7 M4 ita hy a i! a j \ | i ri ay; ved Vey Wey | { Wa if ) he! a HOW iY eit ty V4 Pye | { : rm a oe ' a | hy i ty ‘ « f ty +] ‘ 5 J \ | I f | ff Wy gs | an an ff pig \} Ny Ni. { { \ \ lf j dt ] i! A lif al a b c d e . Proximal end, showing sicula. Dobb’s Linn; Birkhill Shales. worth. Coll. Lap- . More distal thece. Part of specimen on same slab as Fig. 272 a. Thee preserved in relief. Llanys- twmdwy, near Criccieth; Llando- very beds. Coll. Fearnsides. . Thece, showing appearance of intro- verted apertural margins; in relief. Enlargement of part of Pl. XL, fig. 1b. . Distal thece, compressed. Enlarge- ment of part of Pl. XL, fig. 1c. Description.—The polypary is very long, slender and flexed, the curvature being, however, generally dorsal; the proximal end is very slender (though not so slender as in M. Sandersoni), but widens fairly rapidly to the maximum breath of 5 mm. The sicula has a length of fully 3 mm., and reaches to the level of the aperture of th. 1 which arises from a point about half-way along its length. The theese resemble those of M. Sandersoni, but the introversion of the apertural margin appears to be slightly less marked. Affinities.— Monog. mcommodus is clearly related most closely to M. Sandersoni; but while the curva- ture in M. incommodus is mainly dorsal or irregular, in M. Sandersont it is invariably ventral; and the polypary is rather more robust at the proximal end. Horizon and Localities. — Llandovery (Birkhill Shales), zone of M. cyphus. S. Scotland: Dobb’s Linn; Belcraig Burn, ete. Lake District: Skelgill. Ireland: Coalpit Bay, Donaghadee; Mill Sluce below Slate Quarry, Wales: Rheidol Gorge, Pont Erywd; Pary’s Pomeroy. Conway ; Mountain, Anglesea; Llany- stwmdwy, near Criccieth. Associates, etc.—Monog. tncommodus is a fairly common fossil in the zone of M. cyphus; it is commonly associated with Monog. cyphus, M. revolutus, M. Sandersoi, M. atavus, various Dimorphograpti, and Climacog. medius. Collections.—Sedewick Museum, Geological Survey of Scotland, Geological Survey of England and Wales, Fearnsides, Jones, Lapworth, and the Authors. MONOGRAPTUS. 407 Monograptus tenuis (Portlock). Plate XL, figs. 2a—e. 1843. Graptolites tenuis, Portlock, Geol. of Londonderry, p. 319, pl. xix, fig. 7. 1868. Graptolites discretus, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, p. 539, pl. xx, figs. 12—14. 1876. Monograptus tenuis, Lapworth, Geol. Mag., dee. ii, vol. ii, p. 319, pl. xi, figs. 3h, k,l, m, n. Polypary of great length, shghtly arcuate throughout, widening gradually from an exceedingly slender proximal portion till the maximum breadth of 1 mm. is attained. 'Thecz seven to five in 10 mm., long and narrow, with distinct sigmoid curvature, overlapping one-third to one-half their length; those of the proximal portion with abrupt expansion in the apertural region and usually introverted, those of the distal portion even and slightly introverted. Description.—The polypary must have had a length of fully 10—15 em., and though in the extreme proximal portion it Fias. 273 a—d.—Monograptus tenuis (Portlock). é : ‘ appears to widen very gradually, it attains its maximum breadth at a comparatively 7 Sy early stage, usually within the first 4 or nf } sed 5 em. of its length. Rf 2 ; j ‘a4 The thecz are long and slender; they i | ~% show a sigmoid curvature of their walls as in 4 f 7s et the genus Leptograptus, but the apertural : margin, while always tending to be intro- ‘\ a 4 verted, is not always conspicuously so, owing to the effects of compression upon the thecz, | which expand abruptly in the apertural @ b ¢ d region. In the proximal portion this may a. Proximal portion. Enlargement of part of give rise to an appearance of retroversion Pl. XL, fig. 2c. b. Distal thecs in ordinary profile view. Enlarge- of the apertural margin in some cases (though ment of specimen on same slab as fig. 273 a. 5 e. Thec# not in ordinary profile view, giving jn other cases it is clearly introverted), and appearance of thecal spine. Ibid. d. Distal thece. Enlargement of part of PL. XL, in the case of the mature thece of the distal a portion may tend to the production of an acute denticle. The thecz are distant and overlap each other barely one-half their length. Affinities—For a considerable time Monog. tenwis, Portlock, and M. discretus, Nicholson, have been regarded by some as different species, but an examination of Portlock’s Irish specimens and new material collected from the type locality shows that the two are identical. A distinct form which occurs at lower horizons, and which has been erroneously referred to M. tenwis by various authors, has recently been distinguished and described by Jones as M. atavus. Monog. tenuis differs from M. atarws mainly in the characters of the thece, which are more elaborate than those of M. atavus, in which there is no sudden }= 5A 408 BRITISH GRAPTOLITES. expansion in the apertural region and hence no denticle or appearance of retro- version of the apertural margin. Horizon and Localities:—Llandovery (zone of M. Sedywickit). Ireland: Limehill, Co. Tyrone. S. Scotland: Dobb’s Linn; Belcraig Burn, etc. Lake District: Long Sleddale; Skelgill. Wales: Pary’s Mountain, . Anglesea ; Quarry near River Twymyn, Llanbrynmair; H.S.H. Fuches Gau Farm House, Pont Erwyd, etc. Associates, etc.—Monog. tenuis occurs in some abundance in the M. Sedgiwickit zone, in which it often characterises a distinct band or sub-zone (Lake District and C. Wales). It is commonly associated with Monog. Sedgwickii, M. limatulus, M. argenteus var. cygneus, Glyptog. serratus, and Climacog. scalaris, ete. Collections.—Geological Survey of Scotland, Geological Survey of England and Wales, British Museum (Natural History), Sedgwick Museum, Greenly, Jones, Lapworth, and the Authors. Monograptus argutus, Lapworth. Plate XL, figs. 3 a—e. 1876. Monograptus argutus, Lapworth, Geol. Mag., dec. ii, vol. ili, p. 318, pl. x, figs. 13 a—e. Polypary several cm. in length, arcuate distally, and involute proximally, widening steadily to a maximum Fras. 274 a—f.—Monograptus argutus, Lapworth. = breadth of 1:5 mm. Thece eight { . . . . a (4 (e} in 10 mm., with conspicuous sig- i |} 4] 0 : \ ik ro moid curvature of their walls, +" + H . : | At | ©) overlapping fully one-half their se \\ } ae Le easy en cy | ¥) length, and with introverted and y! 1 oe i . . AY fe ar] shghtly introtorted apertural ts ‘ rt) ate ot i z margins opening within pouch- a, € | | shaped excavations. # | > # . . . y . | Pay Description.—The polypary is slender We 4 \ f e . os . p ‘ te HH 113 and several cm. in length; it is fairly 4 a ; } . . . . . robust in the initial portion, and the a b (v d e ap a. Proximal portion,showing dorsaleurvature. Enlarge- increase in width takes place wholly ment of part of Pl. XL, fig. 3b. ; within the first few cm. of length, so b. Portion near proximal end; preserved mainly as a 5 cast. Skelgill; Stockdale Shales. Coll. Lapworth. that distal fraoments have a uniform ec and d. Portions of same specimen, showing the different =) appearances presented by the thece. Parts of speci- ] yreadth. men on same slab as fig. 274 b. 5 s ; e. Adult thece; preserved partly as a cast, partly in The theese do not exceed 3 mm. in relief. Enlargement of part of Pl. XU, fig. de. ; ‘ f. Adult thece, compressed. Another part of specimen length ; in their general characters— fie. 274 e. namely, the pronounced sigmoid curva- ture of their walls and the introversion and introtorsion of the apertural margin— MONOGRAPTUS. 409 they show a decided approach to the type regarded as characteristic of the genus Dicellograptus. Affinities. to M. revolutus, but the characters of the thecz are distinct and, deed, unique In the form of the polypary Monog. argutus comes, perhaps, nearest amongst the Monograpti. Horizon and Localities—Llandovery (Birkhill Shales), top of zone of M. gregarius. S. Scotland: Dobb’s Linn. Wales: Old Quarry 270 yards N.E. Gwen-ffrwd Uchaf Farm House, Pont Erwyd, ete. Lake District: Skelgill. Associates, ete.—Monoq. argutus is a fairly abundant fossil in the Upper Birkhill Shales, immediately below the zone of M. convolutus, at a horizon corresponding with the M. argenteus band of the Lake District and the M. leptotheca band of the Pont Erwyd locality. It occurs associated with Monog. leptotheca, M. Clingani, M. communis, and other forms. Collections —Sedgwick Museum, Geological Survey of England and Wales, Jones, Lapworth, and the Authors. Group III. Monograpti in which the mature thece are short tubes with abrupt sigmoid curvature and some torsion of the thecal axis, so that the apertural margins show occasionally within distinct excavations in the ventral margins. The thecz in this group show an approach in character to those of the I. priodon type, but the apertural region is adnate instead of isolate and the torsion of the thecal axis is but sight. There is often an appearance of narrowing towards the apertural margin, but this is largely, if not entirely, induced by the torsion of the thecal axis. Asa result of this torsion the polypary viewed in the one aspect shows thecz resembling those of M. dubius, while in the other they resemble those of Climacograptus. The polyparies are approximately straight or shghtly flexed. Monograptus vomerinus (Nicholson). Plate XLI, figs. 1 a—e. 1850. Graptolithus colonus, Barrande, Grapt. de Bohéme, pl. ii, fig. 4. 1851. Graptolithus colonus, Suess, Bohmische Graptolithen, pl. viii, figs. a—/. 1868. Graptolites priodon, Nicholson, Quart. Journ. Geol. Soc., vol. xxiv, pl. xx, figs. 7, 8. 1872. Graptolites vomerinus, Nicholson, Monog. Brit. Grapt., p. 53, fig. 21. 1876. Monograptus vomerinus, Lapworth, Geol. Mag., dec. ii, vol. iii, p. 353, pl. xii, figs. 6 a—e. 1900. Monograptus vomerinus, var. a, Elles, Quart. Journ. Geol. Soe., vol. lvi, p. 403. Polypary 1—8 em. in length, approximately straight, or slightly flexed at the proximal extremity, widening rapidly from an initial breadth of ‘4 mm. to a maximum of about 2 mm. within a short distance of the proximal end. 4.10 BRITISH GRAPTOLITES. Sicula conspicuous. Thece short, eleven to ten in 10 mm. with shght ogee- form curvature, overlapping about one-half their length, and having their apertural margins either everted or appearing in distinct excavations. Description.—Vhe polypary varies very much in size, but all fragments of the initial portion show the characteristic rapid widening, the maximum breadth being attained within 2°5 em. of the proximal end. The conspicuous sicula has a length of fully 1-5 mm. and reaches well above the level of the aperture of th. 1; its outer wall is slightly curved, but the inner Fras. 275 a—f.—Monograptus vomerinus, Nicholson. continues the straight line of the dorsal wall of the polypary. % All the thecz are short, the distal fi Z ones having a length of only 1°5 mm. Wa and the proximal ones are much shorter j, | rae | / fi a . . . ra ‘i YP with the exception of th. 1, which has ” 3 4 ie ggita 4 ak , - Ny ; i MS alength of lmm. The thecv present <4 4 “y ‘hg : . wa Ny yh ko ive various appearances according to the (ca | ‘34 a | fe - ! #’ «| . ehyie . rf OM as OU fa different conditions of preservation. a OL we. : i \ | yf oe Sometimes they seem to have abrupt \ ‘ V FE i : : A <4 3 Zag yee sigmoid curvature and the apertural v N ya ie margins are situated within distinct hi / \4 Se : 3 : }/ 9 Yee excavations occupying about one-third \ 4 of the total breadth of the polypary a b c d e if : a ane : . a i) panna) ond, showing sicula; preserved as a cast. (Fig. 275 f). This is their most vuthin Roz anoollen : 5 2k S 1 (hes q Bt 4 Cure iy ae Seg ln Shales (zone of characteristic aspect. The thece of b. Proximal end, showing sicula, preserved in relief. Lledewm Stream, Newydd Fynyddog, nr. Llanbrynmair ; Wenlock Shales. Coll. Wood. . Thece near proximal end ; in full relief, showing torsion of thecal axis, Ibid. curvature characteristic of A. priodon d. Adult thece. seen partly from the back so that the SS ee concealed. Enlargement of part of Pl. (Fig. 279 ¢), and in this case their » fig. Le. s Specimens preserved in relief, how- ever, show a tendency to the ogee S €. moe eee with apertures facing the observer. Reverse apertures are either very conspicuous _ _ side of Fig, 275 d. qs B 1 f. Adult thece as they usually appear in a compressed (Fig. 270 c) or wholly concealed (Fig. specimen. Pencerrig, nr. Builth; Wenlock Shales 275 ] (zone of Cyrtog. Murchisoni). Coll. Elles. aor ). Inthe most characteristic view the thecz obviously recall those of Climacograptus, but it is clear that the thece cannot have been quite so simple in form, and there must have been some torsion of the axis of the thece in order to account for the different appearances after compres- sion (Figs. 275 a—f). Affinities —Monog. vomerinus is very closely related to all its varieties, and from most of them it is indistinguishable in the distal portion. The proximal ends are, however, distinct, and in var. crenulatus the thecal apertures are narrower than in the typical form, while in var. basilicus the polypary is altogether more robust. Horizon and Localities.—Wenlock Shales (all zones). MONOGRAPTUS. 411 Lake District: Southwaite Wood; Austwick Beck; W. side Long Sleddale, ete. Wales: Benarth Shore, Conway; Rose Mill Farm, Conway; Pencerrig; Trecoed, near Builth; R. Irfon, near Builth; Corwen; Ruthin Road, nr. Llangollen; Tarannon District. Scotland: Riccarton. Associates, ete.—Monog. vomerinus is a common fossil throughout the Wenlock Shales; it seems to make its first appearance in their passage beds below, but is especially abundant in the Lower Wenlock Beds, where it occurs associated with Cyrtog. Murehisont, Monog. priodon, Gladiog. Geinitzianus, and other forms. At higher horizons it may be found with any of the zone fossils, and with M. Flemingit and M. dubius. WGaeoTG a and: b= Wonouranbus. cline: Collections—Sedegwick Museum, Lapworth, and rinus, var. basilicus (Lapworth). the Authors. ete . , ete. , f / af Pods us Ve ‘ Var. basilicus, Lapworth. Plate XLI, figs. 2 a—d. ee | j k Lax / 1880. Monograptus galaensis var. basilicus, Lapworth, Ann. ¥i : / , Mag. Nat. Hist. [5], vol. v, p. 152, pl. iv, figs. 6 a, 6 b. ve 9 I / | | | fi | i /é In var. basilicus the polypary is far stouter than 0 iy (area A in M. vomerinus, attaining a breadth of at least 3 y ; i Paes mm., and occasionally even more. The thece are ae) i Se ris very similar in form to those of M. vomerinus, but 4 is KG overlap for fully two-thirds of their length. “MM PR Horizon and Localities—Wenlock Shales (zones | (HEY fp of Cyrtog. Murchisoni to Cyrtog. Linnarssont). fa in? / Wales: Pencerrig, Builth, Builth Road, etc. ny} ieee Var. basilicus is fairly common in the Lower ¥) Pena ad Wenlock Shales of the Builth area, where it occurs \y Std Sa ale 2 associated with Cyrtog. Murchisoni, Monog. priodon, a. Proximal end, Enlargement of pat Md. vomerinus, M. viccartonensis, Cyrtog. Linnarssont, of Pl. XLI, fig. 2d. : ane b. Adult thece, showing different ap- and other forms. pearances presented according to varying compression. Enlargement of part of Pl. XLI, fig. 2c. Collections.—Lapworth and the Authors. A » ya — gs. 3 a ile Var. gracilis, var. nov. Plate XLI, fi 1900. Monograptus vomerinus, var. B., Elles, Quart. Journ. Geol. Soc., p. 405, fig. 16. Var. gracilis differs from M. vomerinus in having the whole proximal portion gracefully recurved; the polypary also widens more gradually, and its width rarely Fia. 277.—Monograptus vomerinus, var. gracilis, nov. 12 _ : Me. x _ ‘nee 2% Pd EEE NE LY a a” -¥ a= hy f Proximal end, showing sicula. Castle Crab, nr. Builth ; Wenlock Shales. Coll. Elles. Var. crenulatus (‘T6rnquist). 1881. 1892. 1900. Fras, 278 a—e.—Monograptus vomerinus, var. Ves 2 crenulatus (Tornquist). 0 Gh ii Atle! ' J SX ™“s d e Q a b a. Proximal end, showing sicula. Tarannon River, near Dolgau Farm; Dolgau Beds. Coll. Wood. b. Adult thece; in relief. part of Pl. XLL, fig. 4b. c. Adult thece ; preserved as a cast. same specimen as Fig. 278 b. d. Adult thece ; preserved so that apertures are concealed. Enlargement of part of specimen on same slab as Figs. 278 band c. e. Specimen inrelief, showing thecal apertures. Enlargement of part of Pl. XLI, fig. 4c. Enlargement of Part of mm. in length. BRITISH GRAPTOLITES. exceeds 1°6 mm., while the sicula is short, measuring The thece number thirteen in 10 mm. Horizon and Localities—Wenlock Shales (zone of Cyrtog. Murchisont). Wales: Pencerrig, near Builth. Scotland: Rie- carton. Associates, etc.—So far as our present knowledge extends var. gracilis is confined to the basal zone of the Wenlock Shales. Collections.—Lapworth and the Authors. Plate XLI, figs. 4 a—d. Monograptus crenulatus, Tornquist, Geol. Foren. Forhandl., Bd. v, p. 438, pl. 17, fig. 4. Monograptus crenulatus, Tornquist, Siljansomradets Graptol., ii, p. 11, pl. i, figs. 12—16. Monograptus vomerinus, var. y, Elles, Quart. Journ. Geol. Soc., vol. lvi, p. 405, fig, 15. In addition to the varieties of Monog. voie- rinus enumerated above, there occurs at the top of the Tarannon Shales and ranging thence into the lowest Wenlock Beds, a characteristic variety which is certainly their forerunner ; this has been regarded as a distinct species, but it is best considered as a variant of the typical M. vomerinus, in which the thece are more closely set in the proximal portion (thirteen to ten in 10 mm.), and the apertural excavation is smaller (one-fifth the total breadth of the polypary). The proximal end is practically straight ; the sicula has a length of 1:5 mm., but unlike that of the typical form the first theca is so short that the apex of the sicula reaches to the level of the aperture of th. 2. , Horizon and Localities. — Gala-Tarannon (zone of M. crenulatus). Wales: Benarth Wall, Conway; Neckar- mount Road, Conway; Tarannon River; Afon Jaen, between Dolfach and bridge below Pen-y-graig, Llanbrynmair; Plasbach Stream, Llanbrynmair; stream east of Lledewm, Llanbrynmair, etc. MONOGRAPTUS. 413 Associates, etc.—Var. crenulatus is commonly found with Monog. priodon and M. subconicus. Collections. —Lapworth and the Authors. Monograptus griestoniensis (Nicol). 1850. Plate XLI, figs. 5 a—d. Graptolites griestoniensis, Nicol, Quart. Journ. Geol. Soc., vol. vi, p. 63, fig. 2. Polypary several em. in length, slightly flexuous, widening from a very slender proximal extremity to a maximum diameter of *7 mm. Fias. 279 a—f.—Monograptus griesto- niensis, Nicol. ae a T “ SSS ere t fl ‘ ; Oe ee eee i A i on j 1 wT i! vA i i r jy @ f ome 1 | fe / \ a i ht d a b d ii a, Proximalend,showing sicula. Taran- non River, below Dolgau Farm ; Talerddig Grits. Coll. Wood. b, Proximal end. Enlargement of part of specimen on same slab as Pl. XULI, fig. 5 d. c. Distal thee ; compressed. Enlarge- ment of specimen on same slab as Pl. XUI, fig. 5c. d, Distal thece ; in relief. Afon Cwm Calch, nr. Talerddig; Talerddig Grits. Coll. Wood. e. Distal thece ; compressed. Ibid. f. Thece preserved with the dorsal side uppermost, giving characteristic “ vertebre-like” appearance. Same locality as Fig. 279 a. Coll. Wood. Thecee ten in 10 mm., with abrupt sigmoid curvature and horizontal apertural margins, situated in dis- tinct excavations occupying fully one-third of the total breadth of the polypary. Description.—The polypary 1s commonly some- what curved, having the thece on the concave margin; there is, however, some variation in the amount of curvature in the specimens from different localities. Most of those from Grieston Quarry are conspicuously flexuous, while those from the Rhay- ader country tend to be less curved, and those from the Tarannon district are, as a rule, so little curved that fragments appear almost straight and rigid; there would appear to be, however, all degrees of curvature between the extreme types. The poly- pary is extremely slender near the proximal end, not exceeding *2 mm. in width, and the breadth increases very gradually until the maximum of ‘7 mm. is attained. The sicula is fairly conspicuous, measuring *6 mm. in length and reaching nearly to the level of the aperture of th. 1. The thecz in the maturer parts of the polypary have a length of fully 2 mm.; they overlap one-half their length or rather less, and the apertural excava- tions are conspicuous, especially in sub-scalariform views. = Ss o {2) i 3 (e) — = = al 3 cS) ala aaa eae ZBL ATO TIA. : Ease ze 5 : : ~ 5 =e nies Oikos a MEE Tea BS * = : S : ° GINA > 0 AEE 8 BS ; : x eLo at Se eNO PODS va N © * BOT ee DIDT Ap OSES SSE APR NSN Rees SS Sata, O By 1 al ) Ti . ° ee ee me pol : Zw. DETECT apg? LAG LI GIG EPL IEEP CDP CEE TOTAAL GEE a eee dEZ ~mas Se . C a a ag =: 2 es x . rm oS = a aa Ses PP CPEPEOCR IT Tee f Sox fers . Rather narrow specimen, showing recurved proximal thece. Vicarage Road, Builth. Lower Ludlow Shales. Sedgwick Museum. 8 c. Broad specimen, in low relief, figured Wood, loc. cit., fig. 10D. Adferton, near Ludlow. Lower Ludlow Shales. Hopkin- son’s Collection. 8 d. Characteristic specimen, figured Wood, loc. cit., fig. 10c. River Irfon, Builth. Lower Ludlow Shales. Wood’s Collection. 9 a—c.—Monograptus colonus (?), var. ludensis (Murchison). (Page 394.) 9a. Complete specimen, figured Wood, loc. cit., fig. 11. Llanfair, Montgomeryshire. Ludlow Beds. Dr. Humphreys’ Collec- tion, Llanfair. 9b. Fairly complete specimen. Llanfair, Montgomeryshire. Ludlow Beds. Wood’s Collection. 9 ¢. Narrower specimen, showing sicula. Ibid. 10 a—c.—Monograptus colonus, var. compactus, Wood. (Page 393.) 10 a. Type specimen (somewhat broken), figured Wood, loc. cit., fig. 12. Hlton-Evenhay Lane, near Ludlow. Lower Ludlow Shales. Wood’s Collection. 10 b. Well-preserved specimen. Stormer Hall, near Leintwardine. Lower Ludlow Shales. Wood’s Collection. 10 ¢. Small specimen. EHlton-Evenhay Lane. Lower Ludlow Shales. Sedgwick Museum. PLATE XXXVIII. = SSS Ba \ ee g yy os . syengh } \ 2 oa SA (3) : ee caeem 3 f Sa Sic ie a. AS BS ee ae ~ ~ . BITAACBTA \ A! a Tee St | meen Teen ees 10¢. 10 b. PALZONTOGRAPHICAL SOCIETY, 1910. 4a. 3 © — 2 Se OS neat Rs bog CRP Sp — wt Se __SSESAN SESSA ROR __ SSS SESS Sow =, — Rea, | RA ACR ARIE: BESSANaatete setae ‘ 10a. 9c. 9b. 8b. Be. 8d. 8a. 74. MONOGRAPTUS. Bemrose Ltd., Derby. M,. Rk. WOOD, del. BRITISH GRAPTOLITES, ‘ SSS NS Sy js ee ee iS Ws ; a \ ~ y ite ed a Ts j i” vy) ih se tices NG —- as sl x pe ; - = 7a. WSS IDA SLATER & E. PAH XXX Monograptus—continued. Figs. 1 a—d.—Monograptus atavus, Jones. (Page 403.) la. Proximal portion, figured Jones, Quart. Journ. Geol. Soc., vol. Ixv, p. 532, fig. 18 a, Rheidol Gorge. Rheidol Group. Geological Survey of England and Wales (23706). 1b. Straighter and more median fragment. Rheidol Gorge, 235 yards 8. of Bryn-chwith Farm, Pont Erwyd. Rheidol Group. Geological Survey of England and Wales. le. Median fragment with dorsal curvature, figured Jones, loc. cit., fig. 18d. Ibid. (23711). ld. Long fragment with ventral curvature. Same locality as fig. 1 b. 2 a—d.—Monograptus Roemeri (Barrande). (Page 397.) 2a. Typical specimen, figured Wood, Quart. Journ. Geol. Soc., vol. lvi, pl. xxv, fig. 13 a. Trefnant-Middletown Brook, Long Mountain. Lower Ludlow Shales (zone of M. scanicus). Wood’s Collection. 2b. Distal fragment, figured Wood, loc. cit., fig. 13 B. Ibid. 2c. Somewhat narrower specimen, in relief. Helm Knot, Dent. Coniston Grits. Sedgwick Museum. 2d. Characteristic specimen, well preserved. Dudley. Ludlow Shales. University of Birmingham. 3 a—d.—Monograptus chimera (Barrande). (Page 398.) 3a. Typical specimen, figured Wood, loc. cit., fig. 188. Stream from Ucheldre to Trewern Bridge, Long Mountain. Watts’ Collection. 3b. Fairly complete specimen, figured Wood, loc. cit., fig. 184. Elton-Ludlow Road. Lower Ludlow Shales. Wood's Collection. 3c. Proximal portion. Ibid., fig. 18 c. 3d, Small specimen. Ibid., fig. 18 p. 4a—c. Monograptus chimera, var. semispinosus, Elles and Wood, nom. noy. (Page 401.) 4a. Complete specimen. Stormer Hall, near Leintwardine. Lower Ludlow Shales. Wood’s Collection. 4b. Narrower specimen. Ibid. 4c. Type specimen, figured Wood, loc. cit., fig. 20. Elton-Ludlow Road. Lower Ludlow Shales (zone of M. scanicus). Wood's Collection. 5 a—d.—Monograptus chimera, var. Salweyi (Hopkinson). (Page 400.) 5a. Complete specimen, figured Wood, loc. cit., fig. 194. Stormer Hall, near Leint- wardine. Lower Ludlow Shales. Wood’s Collection. 5b. Type specimen, showing long virgula, figured Lapworth, Ann. Mag. Nat. Hist. [5], vol. v (1880), pl. iv, figs. 2a and b. Stormer Hall. Lower Ludlow Shales. Hopkinson’s Collection. 5c. Narrow specimen, cast, showing thecal spines well. Stormer Hall. Lower Ludlow Shales. Wood’s Collection. 5d. Reverse of fig. 5c, in relief, thecal spines very inconspicuous. — Ibid. 6 a—e.—Monograptus varians, Wood. (Page 395.) 6a. Type specimen, figured Wood, loe. cit., fig. 144. Old Dingle Mill, Long Mountain. Lower Ludlow Shales. Wood’s Collection. 6b. Broader specimen, figured Wood, loe. cit., fig. 148. Road above Garbett’s Hall, Long Mountain. Lower Ludlow Shales. Wood’s Collection. PLATE XXXIX—continued. Pies. 6 a—e.—Monograptus varians, Wood (continued). 6c. Distal portion, showing virgula. Loe. cit., fig. 164. Stormer Hall, near Leintwar- dine. Lower Ludlow Shales. Wood’s Collection. . 6d. Complete specimen. Loc. cit., fig. 15. Elton Lane, near Ludlow. Lower Ludlow Shales. Wood’s Collection. 6 e. Complete specimen, cast, figured Lapworth (as M. colonus), Ann. and Mag. Nat. Hist. [5], vol. v, pl. iv, figs. 3b and 3d, and Wood, loc. cit., fig. 168. Mary Knoll, near Ludlow. Lower Ludlow Shales. Hopkinson’s Collection. 7 a—-e.—-Monograptus varians, var. pumilus, Wood. (Page 396.) 7a. Type specimen, preserved so as to appear narrower than usual, figured Wood, loc. cit., fig. 17 8. Elton Lane, near Ludlow. Lower Ludlow Shales (zone of MM. scanicus). Wood’s Collection, 7b. Co-type, somewhat wider, figured Wood, loc. cit., fig. 17a. Ibid. 7c. Small, but typical specimen. Elton Lane. Lower Ludlow Shales. Wood’s Collection. 7d. Specimen on same slab as fig. 7c. 7 e. Complete specimen, on same slab as figs. 7¢ and 7 d. 8 a—f.—Monograptus leintwardinensis, Hopkinson. (Page 401.) 8a. Type specimen, figured Wood, loc. cit., fig. 21a. Church Hill Quarry, near Leint- wardine. Lower Ludlow Shales (zone of M. leintwardinensis). Hopkinson’s Collection. 8b. Co-type, figured Wood, loe. cit., fig. 218. Ibid. 8c. Long narrow specimen. Church Hill Quarry, near Leimtwardine. Lower Ludlow Shales. Fearnsides’ Collection. 8d. Broader specimen. On same slab as fig. 8 ¢. 8e. Short, broad specimen, On same slab as figs. 8¢ and d. 8f. Characteristic specimen. On same slab as figs. 8 c—e. 9 a—d.—Monograptus leintwardinensis, var. incipiens, Wood. (Page 402.) 9a, Type specimen, figured Wood, loc. cit., fig. 22a. Montgomery Road, Lower Ludlow Shales. Wood’s Collection. 9b. Co-type, figured Wood, loc. cit., fig. 228. Long Mountain. Lower Ludlow Shales. Watts’ Collection. 9c. Short broad specimen. Same locality as fig. 9 a. 9d. Very long specimen. On same slab as fig. 9b. 10 a—e.—Monograptus Sandersoni, Lapworth. (Page 404.) 10a. Median fragment. Dobb’s Linn. Birkhill Shales. Lapworth’s Collection. 10b. Proximal fragment, with strong ventral curvature, figured Lapworth, Geol. Mag., 1876, pl. xi, fig. 2e. Dobb’s Linn. Birkhill Shales. Lapworth’s Collection. 10c. Distal fragment with conspicuous ventral curvature. Coalpit Bay, Donaghadee. Llandovery Beds. Sedgwick Museum. 10d. Distal fragment, with only slight curvature, in low relief. East bank of road from Pont Erwyd to Devil’s Bridge, 50 yards E.N.E. of Bryn-chwith Farm. — Rheidol Group. Geological Survey of England and Wales. l0e. Long distal fragment. Dobb’s Linn. Birkhill Shales. Lapworth’s Collection. PALZONTOGRAPHICAL SOCIETY, 1910. PLATE XXXIX. BRITISH GRAPTOLITES. te ae see etgeD eae Ue ae SA bi +e BIG WA 6 N 2 9b. OPES cS) nero + WSs 98 Gaae = 3 wi o MESA SA o 4 £ % Re 5 ERE O Se. D as ASA ss _ebatosteesssaptte 0 a ee MONOGRAPTUS. Bemrose Ltd., Derby. WOOD, adel, & EF. M. R. IDA SLATER PLATE Xi: Monograptus—continued. Fies. 1 a—e.—Monograptus incommodus, Tornquist. (Page 406.) 1 a. Long distal fragment. Skelgill. Skelgill Beds (zone of Dimor- phog. confertus). Sedgwick Museum. 1b. Proximal fragment, showing characteristic double curvature. Dobb’s Linn. Birkhill Shales. Lapworth’s Collection. 1c. Distal fragment. Dobb’s Linn. Birkhill Shales. Sedgewick Museum. 1d. Small distal fragment, partly im relief. Rheidol Gorge. Rheidol Group. Geological Survey of England and Wales. 1 e. Median fragment. Dobb’s Linn. — Birkhill Shales. Lapworth’s Collection. 2 a—e.— Monograptus tenuis (Portlock). (Page 407.) 2a. Specimen on Portlock’s type slab, showing general form of poly- pary. Limehill, Co. Tyrone. Upper Llandovery Beds. Geo- logical Survey of England and Wales. 2b. More distal fragment. On same slab as fig. 2 a. 2c. Small proximal fragment, cart track, 10 vards west of entrance to lower quarry, 550 yards H.S.H. of Fuches-gau Farm-house, Pont Erwyd. Castell Group. Geological Survey of England and Wales. 2d. Distal fragment. On same slab as fig. 2 c. 2 e. Proximal portion, labelled by Nicholson as Monograptus discretus. Skelgill. Skelgill Beds. British Museum (Natural History), S. Kensington. 9 3 a—e.—Monograptus argutus, Lapworth. (Page 408.) 3a. Type specimen, showing general form, partly figured Lapworth, Geol. Mag., 1876, pl. x, fig. 18 b. Dobb’s Linn. — Birkhill Shales. Lapworth’s Collection. 3b. Proximal portion, showing curvature. §. side of old quarry, 270 yards N.E. of Gwen-ffrwd-uchaf Farm, Pont Erwyd. Base of zone of M. convolutus. Geological Survey of England and Wales. 3c. Proximal portion, (?) figured Lapworth, loc. cit., fig. 13 a. Dobb’s Linn. Birkhill Shales. Lapworth’s Collection. 3d. Proximal fragment. Rheidol Gorge, 440 yards 8.S.H. of Bryn- chwith Farm-house, Pont Erwyd. Base of zone of M. convolutus. Geological Survey of England and Wales. 3 e. Distal fragment, part in relief, part impression. On same slab as reverse side of fig. 3 d. PLATE XL. awe G H | \ De \ Spee 9 ae =”. la ite Se = a a ee Se. Bemrose Ltd.,’ Derby. BEC 8 a. MONOGRAPTUS. PALZONTOGRAPHICAL SOCIETY, 1910. BRITISH GRAPTOLITES. We Sees; ED AS rip SD ITS ITT Se ee ie ee ere EE es. ne a= = SSD ees ee ee ae a a IIE MELT OTA oes aS 1b. a. del. WOOD, M. R. & £. IDA SLATER PGA Re xa Monograptus—continued. Fics. 1 a—e.—Monograptus vomerinus (Nicholson). (Page 409.) 1 a. Typical specimen, impression, (?) figured Lapworth, Geol. Mage., 1876, pl. xu, fig. 6a. EHlhotsfield, S. Scotland. Riccarton Beds. Lapworth’s Collection. 1 6. Smaller specimen, in full relief. Lledewm Stream, Newydd Fynyddog, near Llanbrynmair. Wenlock Shales (zone of Oyrtog. Murchisoni). Wood’s Collection. 1c. Specimen, partly in relief, part cast. West side of Long Sleddale, Lake District. Base of Coniston Flags. Lapworth’s Collection. 1d. Distal fragment, impression. Rig Burn, River Hsk, near Lang- holm. Wenlock Beds. Geological Survey of Scotland, Edin- burgh. le. Long distal fragment, with apertures facing the observer. West of Wharfe, Lake District. Lower Coniston Flags. Sedgwick Museum. 2 a—d.—Monograptus vomerinus, var. basilicus (Lapworth). (Page 411.) 2a. Typical specimen. Cutting, Wellfield, near Builth. Wenlock Shales (zone of Cyrtog. Linnarssont). Lapworth’s Collection. 2b. Distal fragment. Wellfield, near Builth. Wenlock Shales. Lapworth’s Collection. c. Type specimen, figured Lapworth (in part), Ann. Mag. Nat. Hist. [5], vol. v, pl. iv, figs. 6 a and). On same slab as fig. 2 a. 2d. Proximal portion. Pencerrig, near Builth. Wenlock Shales (zone of Cyrtog. Murchisont). Hlles’ Collection. iw) 3 a—d.—Monograptus vomerinus, var. gracilis, Elles and Wood,nom. nov. (Page 411.) 3a. Typical specimen, impression. Elhotsfield, 8. Scotland. Ric- carton Beds. Lapworth’s Collection. 3b. Proximal portion. Trecoed, near Builth. Wenlock Shales (zone of Cyrtog. Murchisoni). Elles’ Collection. 3c. Broad distal fragment, impression. On same slab as fig. 3 b. 3d. Proximal fragment, impression. Pencerrig, near Builth. Wen- lock Shales (zone of Cyitog. Murchisont). Elles’ Collection. 4 a—d.—Monograptus vomerinus, var. crenulatus (Tornquist). (Page 412.) 4a. Distal fragment, partly in relief. Tarannon River, just below Dolgau Farm. Dolgau Beds. Wood’s Collection. 4b. Similar fragment, partly in relief. Ibid. PLATE XLI—continued. Fras. 4 a—d.—Monograptus vomerinus, var. crenulatus (Tornquist). (Page 412)— continued. 4c. Proximal portion, in relief. Ibid. 4d. Fragment showing proximal end. Williamshope (?), S. Scotland. Gala Beds. Lapworth’s Collection. 5 a—d.—Monograptus griestoniensis (Nicol). (Page 413.) 5 a. Proximal fragment, specimen on Nicol’s type slab. Grieston Quarry, S. Scotland. Gala Beds. Geological Survey of Hneland and Wales (11,800). b. Distal portion. Ibid. (11,801). c. Proximal portion, showing considerable curvature. Grieston Ox Or Quarry. Gala Beds. Sedgwick Museum. 5) d. Ibid. 6 a, b.—Monograptus cf. griestoniensis. (Page 414.) 6 a. Proximal portion. Tarannon River. Talerddig Grits. Wood’s Collection. 6). Longer specimen, showing rigid form. Afon-cwm-calch, near Talerddig Railway Cutting. Talerddig Grits (upper part). Wood’s Collection. 7 a—e.—Monograptus crenularis, Lapworth. (Page 414.) 7 a. Long median fragment. Dobb’s Linn. Upper Birkhill Shales (zone of Cephalog. cometa). Lapworth’s Collection. 7b. Long distal fragment, impression. ‘lhe Corrie, Dobb’s Linn. Upper Birkhill Shales. Lapworth’s Collection. c. Distal fragment, part in relief, part impression. Ibid. df es | d. Proximal fragment. Ibid. e. Ibid. “J PALZONTOGRAPHICAL SOCIETY, 1910. PLATE XLI. BRITISH GRAPTOLITES. SSE ee os Hi 2 : NST erg eee wo aS caer SRS NS ye gree OS Naa. a ASS SES RS Ap ee Se a Sa: Sac eee Te SASS 5 b. 6 a. SST ne ee enn ee SSE Re mma = om SAOITEEES ee Se nares s&s ees ROE SSG PT RTERE SR So ne oe a, SasSSTs a — 19 VEZ IIE LIFES L TTF DILL ZoF7: =e SRE UGESESSASSSERSES == — = SSASSSSESSEESS, N &F EDGED her Fee el a Ss UI RASS QUST OAT eg nee a FOSS eT Se SOS See OP RG SISSIES ecreeaae 3 ae a pssder| ¢§ eS Se SE Sanaa RON Nee SNe me — BESS tema ae ~ ia) == SoS SRS ee Cee panes Pe. = SESS SSNS — ESE CLEP EID Ss peste seseoese seh eae : SS — eee = = APOE LIE AD ERED PIE LITE, SSS = OT EOD os SES = : : aa PAS IRE ASS RITE INS ERE eR SOOO Da po a IE OSES CET Sapa ed a. 5 d, 6 Db. 4c. Uf 1p Wace 74. ies Maas MONOGRAPTUS. Dey by. Bemrose Lid , WOOD, del. Gee Me RR: IDA SLATER Se a pT be te IR Rh ee eS eet we