i I BINDING LIST MSRi ^ \ 1 TYPE AMMONITES VI > There are two kinds of people in the world — those who pioneer and those who plod. The plodders always attack the pioneers Henry Ford 'Today and Tomorrow.' 1926. p. 2 3. TYPE AMMONITES-VI BY S. S. BUCKMAN With contributions, photographs and/or MS., from F. A. Bather, d.sc, f.r.s., C. C. Gaddum, F. H. Michael, Prof. S. Henshaw, H. G. Herring, B. Thompson, f.g.s., A. E. Trueman, d.sc, J. W. Tutcher, D. M. Williams, b.sc. Vol. VI Pages I — 6i, with Text-iigures 1-3 Plates 192 Published by the Author Sold by WHELDON & WESLEY, Ltd. 2, 3 & 4, ARTHUR STREET, NEW OXFORD STREET, LONDON, W.C. 2 1925— 1927 CONTENTS Vol. VI Page Terminology 5 Systematic 7 Chronological 49 Acknowledgment 5^ Publication Details 52 Synopsis 52 ^denda, Corrigenda 52 ('Plates (192) Mndex • • 53 Made and prinud in Qreat 'Britain by NORMAN, SAWYER AND CO., LTD., ST. GEORGE's HALL CPELTENHAM Terminology Dr. F. A. Bather, F.R.S., of the British Museum (Nat. History) writes : " I have been reading [Type Amm., Vol. V] with deep interest. But I wish you would make it clearer that a genotype or lectogenotype is a species, not a specimen. I really think that this is of some importance. There are passages and especially legends to plates which tend to confusion." Strictly speaking. Dr. Bather is perfectly correct — the genotype is a species ; but as there always can be differences of opinion as to whether certain specimens belong to a species or should be separated, the actual specimen to which the generic name was first applied becomes, when it is positively known as such specimen, the only example about whose identity there can be no dispute. Such original specimen is thus the actual type of reference for determining the characters of the genus. So I have always quite deliberately pinned the genotype species down to the basis of one original specimen. When authors have given a generic name to species without definite fixing on one, I have chosen first one species and then one specimen — a lectogenotype, as Dr. Bather writes, or a genolectotype, as I have written, to be the one definite standard. Thus for the genotype or the genolectotype species there is one and only one actual standard of reference. I have used the term genotype for short instead of writing ' the ultimate standard of refer- ence whereon the genotype species rests, and by which it has to be determined.' The generic name does not follow the cited species, it follows the cited standard specimen : it is the identity of the standard specimen which rules the genotype species, not the name of the cited species which rules the identity of the genotype standard. Oftentimes the attributing of the genotype standard to a given species may be incorrect. For example, I have given the generic name Gigantites to a specimen supposed to be conspecific with Sowerby's Ammonites giganteus (T.A. Ill, CCLVI). This identity may be wrong. If so, the generic name Gigantites remains fixed on my giganteus, whatever that may be ; it does not pass over to Sowerby's Ammonite's giganteus, however often the genotype species of Gigantites may have been cited as being Gigantites giganteus, J. Sowerby sp. I have protected my specimen by definitely placing the word ' Genotype ' in its legend. But, had I not done so, I hold that it should be taken as the ' genotype standard of reference.' It is, therefore, in my opinion, imperative that in giving a new generic name, the author should not merely cite a given species by name, but should cite one definite specimen of that species for the type of his genus ; because the species which he selects may contain many specimens : in his opinion these may be conspecific, but it does not follow that future observers will agree in that view. Then there is trouble as to which form is to be selected : all this is avoided by being TYPE AMMONITES— VI Feb. definite as to one example. Whatever be the species of that one example is then always the genotype species, while the one example always remains the genotype standard of reference. The foregoing was submitted to Dr. Bather, who very kindly sent the following remarks, which he has given me permission to publish : On Genotypes, by Dr. F. A. Bather. As C. Schuchert says, in his introduction to the Catalogue of Type specimens of Fossils in the U.S. National Museum, a genotype is a species, not a specimen. To this statement " strictly speaking " you agree. This being admitted, certain difficulties may arise, as you have foreseen, and as is matter of frequent experience. They are generally due to a misreading of the genotype through failure to study its holotype. The way you have chosen to prevent those difficulties is, in my opinion, illogical. On such matters I am constantly consulted, and the following is the advice which I invariably give. In establishing a new genus an author should fix on one species as the genotype (or genoholotype) . The standard of that genotype is the holotype of the species. Therefore, if there be no holotype, it is his business to select one (lectotype). If possible, he should become personally acquainted with the syntypes, so that he will select an appropriate specimen. In any case, it is to be presumed that he does not venture to make any species the type of a new genus, unless he is familiar with its holotype, since it is by that specimen in the last resort that the genus must be judged. The holotype of the geno- type is the ultimate standard of reference. Now, if the author is prevented by inevitable circumstance or by laziness from doing this work, and if he has to leave others to do it for him — that is to say, if he thinks himself obliged to make a new genus without knowledge of its type-species, because such a course is suggested by a specimen or specimens that he refers to that species, then the follow- ing is the course of action to follow. He should select one of those specimens and say : " If it be found that the genotype or type-species is not what I imagine it to be, i.e., is not conspecific with the specimen before me, then it is to be understood that my new genus is to be interpreted by this specimen, which will be the holotype of, or will fall into, a new species, and that species will be the genotype of my genus." The preceding, you will see, has in the end the same practical result as your action, but is not open to the same criticism. It is, in my opinion, preferable because it does not encourage slovenly work, but urges on the author the need, for studying the actual type-material. I can see no radical difference between Dr. Bather's use of the word genotype and mine, except this : that I use the word I' genotype " quite short where it should be said ' the one standard of reference for the genotype species.' We are both agreed that it comes down ultimately to one specimen. But Dr. Bather has started another hare altogether — that is, the method to be used in choosing a genolectotype out of various examples of a species. He says, in effect, that if an author writes Ab, wherein A is a new generic name, then the holotype of b automatically becomes the genotype standard of reference for the generic name A. I dissent. I say that if Ab represents a multitude of species, as it really did in uncritical days, then all the species of these forms which are known as b prior to the giving of the name A are really genosyntypes, 1926 SYSTEMATIC and that if the author has not, by some means, made indication of selection, then a subsequent author has the right to choose a geno- lectotype out of those genosyntypes : to be precise, he should pin down one definite specimen as the standard of reference. For the holotype of Ab may never have been fixed ; it may be obvious from the author's diagnosis of his genus that he has never seen the original material, so that it is equally plain that the author is giving his generic name to species erroneously identified with Ab. Or, again, if there be a holotype of Ab, it may be so poor a specimen that no one would wish to have it as a genotype standard, because it would give rise to so much diversity of opinion that the' unfortunate A would be hunted from pillar to post, being found one day with one series of characters, and placed with one set of associate species ; another day with quite other sets. This case is different from that considered in my first notes (p. 5 above), which is concerned with an author giving a generic name to three or four distinct species, out of which he has not selected one species to be a genotype. Here a subsequent writer is free to choose a geno- lectotype species out of these genosyntypes ; but, again, in the geno- lectotype species there may be several specimens, and, to avoid confusion, the method of choosing one of these as the genolectotype standard would be followed as noted above. Thus there would be one rule only — whether there be several species Ab, Ac, Ad, or only a series of specimens passing under one name Ab, there is freedom to choose, first one species and then one sp)ecunen of that species, as the genolectotype standard. Dr. Bather's dictum that an author should always consult the holotype before giving a name is a counsel of perfection ; but it is scarcely practicable. Types are scattered all over the globe. Lack of health and lack of means, two interdependent afflictions of many scientific men, would effectually bar the necessary travelling. For just such reason I hold that the material which an author has under his hand, especially if he has used it in description or illustration, even without having actually mentioned it as genotypical, should take precedence. The genotype should go with what the author has seen, and not with what he may not have seen. If the author's b turns out to be a prior-named or a post-named c, then the genotype follows c, not b ; but the author's specimen of c may not be the holotype of c : it may be a plesiotype, or it may be a paratype. Therefore, with much regret, I differ from Dr. Bather's statement that ' the holotype of the genotype is the ultimate standard of reference.' In my opinion, the genotype standard of reference is by no means necessarily the holotype of the genotype. If only students will in future be precise in stating which specimen is to be taken as the genotype standard of reference, much trouble would be saved. Unfortunately, such technical details are not impressed on them by their teachers, because the teachers themselves lack the necessary training. Editors, however, could do much by insisting that such details be given. Systematic Suture-line : For the distinction of genera the relative length and development of the lobes of the suture-line is found to be of prime TYPE AMMONITES— VI Feb. importance. Hitherto where this has been recorded in the legend at the foot of the plate, it has been placed in the following full form, SI. EL — , Li — , L2 — , per cent, of whorl-breadth or more concisely EL — , Li — , L2 — of — (whorl-breadth understood). Yet it is advisable, for the saving of space, to record for the future in another manner, congruous with that used for giving proportions. Thus the record will be made in four consecutive items : ist. The breadth of the whorl in millimetres, next the length of EL in so much per cent, of such breadth, next that of Li, lastly that of L2. Thus a set of figures preceded by SI. and reading SI. 20, 45, 54, 23 will indicate as follows : The breadth (or height) of the whorl is 20 millimetres, the external lobe (EL) is in length 45 per cent, of that whorl-breadth, the first lateral lobe (Li) is 54 per cent, and the second lateral lobe (L2) is 23 per cent, of the 20 mm. Beginning with this number (Part 56) the records will be so made. When an item cannot be given, a — will be placed in its position. More and more attention to these suture-line details should be urged on those who desire to identify species of Ammonoids. The whorl-breadth is given in the same way as it is taken in regard to proportions, because where the suture-line is painted in on the specimen and the figure of the specimen is reproduced with such line in place, that is the easiest method for measurement. But when a suture-line is traced off, and is reproduced with the full curve of a gibbous side extended to a straight line, the necessary allowance must be made, for the difference in length of a base-line from a straightened-out curve beyond a base-line of mere length without the curve. The first base-line should be reduced to the amount of the second, a feat easily accom- plished by means of any of the little wheel-measuring instruments. Other proportions may sometimes require to be given, and should be provided for — the Auxiliary lobes and the Internal lobe : they may be marked as A', A" and so on and I, followed by their proportionate figures. A further proportion is important in the cases of Stepheocerates, Perisphinctids and Hke forms — the length of what is known as the retracted inner portion, or the suspensive lobe, or, as the Germans concisely call it, the Nahtlobus, that is the seam lobe or the lobe by the whorl- junction. Nahtlobe seems good to adopt, with the symbol N. The proportion of this lobe when given will come as an item marked by a preceding N. The length of the Nahtlobe is the length of the whole series of lobes which run down the inner part of the whorl inside Li. See, for instance, Cymatosphindes cymatophorus, CDLb. The length is measured from the bottom of the lateral saddle Si, which, in fig. i of the plate referred to, just touches the bottom line of the figure. From that point a line is drawn towards the inner edge to run parallel with the guide-line. Or the same result can be obtained in another way : — measure from base of ES to the guide-line and then add any overplus below the guide-line or deduct any minus quantity short of it. In the figure referred to there is an overplus of not quite 6 mm., the full length of N is 52 mm. The length of base-hne is 49 mm., so the value of N reads as N 103. A good instance of the necessity of attending to the proportions of suture-lines occurs in this work. Three species of Wheatleyites were 1926 SYSTEMATIC named, in one of which, W. redudus, the decrease in length of lobe was attributed to age (phj-logerontism). Subsequently a more aged species of Wheatleyites was found, W. rarescens, which showed that the length of lobe increased. About the same time a less advanced form, congruous in suture-line with W. redudus, was discovered, to be named Shotoverites pringlei. Obviously it is necessary to change Wheatleyites redudtts to Shotoverites reductus (see below, p. 15). Table I, following, shows how 4 specimens (3 species) of Wheatleyites agree in general proportions of suture-line and how the two species of Shotoverites stand together distinct from them. Table I— Wheatleyites & Shotoverites (Suture line, SI.) Wheatleyites tricostulatus, CCCLXV 71, — , 60, 39-5 W. opulentus, CCCLXXXIIIa 79, 56 ? 64, 31 ? W. „ , CCCLXXXIIlB 26-5, 66, 60, 38 W. rarescens, DLXIa, 45, 69, 71, 45 Shotoverites pringlei, DLXII 48, 40, 46, 22 S. redudus, CCCLXXXIV 89, 39-5, 37 [43 ?] 24 The length of Li in S. redudus seems to have been understated : tested on the plate it gives 43 p)er cent. A similar instance of the necessity of taking the proportions of suture-lines occurs in Dr. Neaverson's lately-published work (Amm. Kimm. 1925). He makes a new genus Sphindoceras with genotype S. crassum (li, i). This is a most remarkably longilobate species. With it he associates 5. distans (iv, 3) of which he only gives suture-lines of young stage — practically useless. But I have before me, from a neighbouring brickyard, Mus. Pract. Geol. Collection, an adult specimen of his species : it gives a lobation about 30 per cent, less than Sphinc- toceras. Another genus Dr. Neaverson names Allovirgatites, genotype A. woodwardi (in, i). He does not give the suture-lines at all clearly of this or of other species of his genus, except A. versicostatus (p. 36, fig. B. 6), though, obviously, the specimens show the suture-lines clearly. But the deficiency can be supplied by examples collected by the Geological Survey and myself from various brickyards in the Oxford neighbourhood. The suture-line proportions are given in Table H : — Table H — Sphinxtoceras & Allovirgatites (Suture-lines) Sphindoceras crassum, 11, i, S. distans, M.P.G. Coll. Allovirgatites woodwardi, in, i S.B. Coll. „ versicostatus. Fig. B. 6, p. 36, , HI, 4 tutcheri, M.P.G. CoU. In these suture-line proportions Sphindoceras crassum stands out quite alone, as an exceptionally longilobate form, surpassing even Wheatleyites (see Table I, above), which has quite a good record in this matter. Then all the examples of Allovirgatites yield proportions of about 50 per cent, for EL and Li, both lobes being far shorter than those of Sphindoceras crassum. The lobe-line of Neaverson's Sphinc- 38, 82, 76. 47 47. 52, 53. 34 21, — , 55. 34 29. 52. 52, 34 18, 53. 45. 30 19-5. 50, 50. 26 'I9. 47. 47. 26 126, 45, 49. 30 10 TYPE AMMONITES— VI Feb. toceras distans shows much disagreement with that of his S. crassum, but full agreement with those of species of Allovirgatites. On the first ground the conclusion is reached that, whatever else it may be, Dr. Neaverson's distans is not a Sphinctoceras, and, on the second, that unless there is some character other than suture-line to weigh heavily in the balance, it belongs to the genus Allovirgatites. The slight differences in the proportions of Allovirgatites are easily accounted for. There are, first, indistinctness in the illustrations and, secondly, differences in the base-line. Thus the base-line in a com- pressed-whorled species like A. tutcheri departs little from the base-line which would be yielded on a curve ; but the base-line of a gibbous-sided species like A. woodwardi is much shorter than would be a base-Una measured over the gibbous curve. Therefore a base-line of 26 mm. in A. tutcheri is relatively longer than is a base-line of 26 rnm. in A. wood- wardi. Therefore the proportions of the lobes in A. tutcheri, since they are reckoned in regard to a relatively longer base-Une, would come out shorter than those of A. woodwardi. These figures of sutural proportions are a good illustration of their reliability in the detection of generic affinity. They show, also, how dangerous it is to assign a species to a given genus without taking note of its suture-line. The eye alone is not to be trusted — compass-measure- ment is essential. Nomen nudum : This term is used sometimes quite incorrectly. Mr. C. H. Crickmay speaks (Proc. California Acad. Sci., (4) xiv (3), 1925, p. 77) of " a vast assemblage of nomina nuda — chiefly names applied with no, or with incomplete, description by Alpheus Hyatt." Dr. L. F. Spath (Yorksh. Amm. ; Naturalist, 1925, 359, footnote i) remarks " Simpson's names must be considered to be nomina nuda as much as Hyatt's unfigured Liassic species recently referred to by Crickmay." Dr. Spath's dictum is wholly incorrect so far as Simpson's names are concerned, and Mr. Crickmay's is mainly wrong. Only those names can be called nude which have no covering description of any kind. So long as a name has a covering description, however insufficient it may be, the name cannot be called naked. The covering description may be as exiguous as the fig-leaf aprons credited to Adam and Eve, or as the bathing-drawers which were considered right in the days of my early manhood, but are condemned by the present decadent age ; yet so long as there is a covering, there is not nudity. Hyatt's and Simpson's names, when covered by any description, are not nomina nuda, any more than are the names of Linne, Bruguiere and others. In natural history a description alone is sufficient to establish priority in the naming of a species. Ammonite workers are not a law to them- selves : they must conform to the laws of natural history nomenclature. Insufficiency of description cannot be urged as ground for the rejection of a name — insufficiency is a relative term, and would lead to endless argument. It might be urged that no description is ever sufficient. Of course, figures are desirable. It was to supply the lack of figures which obtained so widely in regard to Yorkshire Ammonites, and were really a stumbling block in the way of their proper study, that this work was commenced. It can, at least, claim to have been successful in figuring a large number of species, which before were only known from descriptions. It can claim to have placed the majority of Yorkshire 1926 SYSTEMATIC ii Liassic species on the surer footing of pictorial representation ; but there is still much to be done. Rejections of names because their types lack illustration is easy, but it is not correct work. Mr. Crickmay took a satisfactory course, that of hunting out Hyatt's types and illustrating them. It is to be hoped that he will continue that good work. However, the possession of a figure of a species does not necessarily end all troubles. A bad figure may cause more worry than no figure at all. Figures may be synthetographs, drawn purposely from more than one specimen, or depicted by oversight of the artist from more than one example. This is the case, presumably, with Young & Bird's figures of Ammonites redcarensis, which now has to be considered. A. redcarensis: Young & Bird's original description (1822, p. 248) is as follows : — " No. 13, PI. XIV, has also [like a maculatus] sharp ribs, and has a sharp keel running along the back. It occurs in the lowest shale at Robin Hood's Bay, and other places. A large shell, generally found imjjerfect, but apparently of the same species, occurs in the Redcar rocks. The a. Bucklandi of Sowerby, Tab. 130, seems to be a cast of this species. We would prefer naming it A. Redcarensis." The figure then given by Young & Bird (photographic copy repro- duced T.A. DCVIII, i) shows in its south-west corner a crinkly line on the jjeriphery. Such crinkly line would not represent the carina of a species like Am. bucklandi or obiustis ; rather, it seems to have been drawn from the crinkly edge shown by ribs on the further side of a ventrally-furrowed specimen — the space in the south and south-west of the figure, between the crinkly line and the line bordering the periphery, representing the ventral furrow. In the second edition (1828, p. 258) the description is very consider- ably altered : — " No. 10, PI. XIV, from the same beds [as A. Bucklandi in the lowest shale at Redcar, and in Robin Hood's Bay] is obviously a different species [from A. Bucklandi], which we have named A. Redcar- ensis. It is a flatter shell, with the aperture more oblong ; and an imperfect keel, where the ribs, which are bent forward, regularly meet in pairs, at a sharp angle, in the form of arrow-heads. It nearly corresponds with Sowerby's A. Turneri, Tab. 452." The figure which is given in this edition differs considerably from that of the first. The periphery has been altered from a crinkly line to a uniform curve, and the whole appearance is that of a carinate- bisulcate like Am. obtusus. Therefore in the first edition the description is that of a carinate- bisulcate ; but the figure is, in part, that of a ventrally sulcate ; in the second edition the description, all except the last sentence, is that of a ventrally sulcate without any doubt, but the figure is that of a carinate- bisulcate. It is a remarkable muddle. What seems to have hapf)ened is this. Young gave the name redcarensis to a ventrally-sulcate specimen like that sent from Whitby Museum (No. 314) as the original of the species. Bird drew the outline of such a shell, but he filled in other details, partly, at any rate, from a carinate-bisulcate, in error. Then Young, not noticing the substitution, drew up his description from the shell which Bird placed before him. In the second edition author and artist, or the two authors, seem to have been again at variance. Young gave a description which would fit a ventrally sulcate, Bird amended his figure so as to depict a carinate- bisulcate. 12 TYPE AMMONITES— VI Feb. This theory of substitution, with consequent confusion, is not in the least unreasonable, for it is fully borne out by what Bird did in regard to A . clevelandicus and A . elegans, as already noticed in this work, Vol. II, No. 109. The figure in the first edition is, therefore, a synthetograph — the specimens which have been used in the drawing of it become syntypes of the species : they are presumed to be the ventrally sulcate, a Schlotheimian and the carinate-bisulcate, an Asterocerate — which should be chosen as lectotype ? The evidence of subsequent authors who have had opportunity to study Young & Bird's material may be given. Simpson, M., 1843, A Monograph of the Ammonites of the York- shire Lias. " [P- 55] IV. With a dorsal furrow only. " 107. A. Redcarensis, Y. & B. " Depressed ; volutions 5 or 6, inner ones J concealed, outer whorl rather more than | the diameter ; radii prominent, diverging, straight along the sides of the whorl, then suddenly bend towards the aperture near the back, where they are terminated by a narrow, smooth space or furrow ; aperture triangular, or sub-quadrate ; diameter 3 inches. " The radii proceed from the inner margin of the whorls, and have the appearance of coarse plaits ; the prominent angles on the back, and the absence of a keel, render this a highly characteristic species ; the sides of the whorls are slightly convex, and the inner edge quickly rounded. From the appearance of the matrix I judge it to be from the ironstone series ; I have a fragment of this species from the oolite of Filey : the flat space on the back is very narrow, and the radii are much more numerous and slender than in the lias specimens." Simpson, M. The Fossils of the Yorkshire Lias, 1855, pp. 100, loi. " [P. 100] IV. With a dorsal furrow only. " 187. A. REDCARENSIS, Y. & B — Volutions 5 or 6, [p. loi] inner ones ^ concealed, outer whorl rather more than J the diameter ; radii prominent, diverging, straight along the sides of the whorl, then suddenly bend towards the aperture near the back, where they are terminated by a narrow smooth space or furrow ; aperture triangular, or sub- quadrate ; diameter 3 inches." " The radii proceed from the inner margin of the whorls, and have the appearance of coarse plaits ; the prominent angles on the back, and the absence of a keel, render this a highly characteristic species ; the sides of the whorls are slightly convex, and the inner edge quickly rounded." " I have now got Young's original Redcar specimen, and I see no difference between it and A. anguliferus. Ph. It is a very variable species. In some the outer whorl is narrower, and the ribs on the back are so depressed as to shew the flat space as a keel ; in others they are so prominent as to form a narrow channel. Some specimens are much inflated, whilst others are much depressed. Mr. Bird's figure is entirely erroneous, and must be intended to represent A. obtusus. Sow. " I have a fragment of a specimen, twice as thick as some, and with coarse and irregular radii. I leave it at present as a variety. — L.L." 1926 SYSTEMATIC 13 Oppel, A., Die Juraformation, 1856, pp. 75, 76, writes : " In Yorkshire erhielt ich Amm. angulatus in mehreren Exemplaren. In den dortigen Sammlungen liegt er entweder mit dem Phillip'schen Namen : Amm. anguliferus , oder nach Young und Bird : Amm. Redcar- ensis bezeichnet. Letzteres mag auf Irrthum beruhen, denn die Young'sche Angabe (pag. 248), dass Amm. Redcarensis einen scharfen kiel trage, stimmt mit der aussern Form des Amm. angulatus nicht iiberein." Blake, J. F., (Cephalopoda, in Tate & Blake, The Yorkshire Lias, 1876, p. 271), says of Aegoceras angulatum Schlotheim : — " This was first recognised by Young and Bird [as A. Redcarensis], but the figure given is erroneous. It was identified by Oppel as belonging to the previously described species of Schlotheim. There are two varieties : (a) most involute, the outer whorl being more than J the diameter — the common Redcar fossil ; {&) less involute, with outer whorl J the diameter, occurring chiefly in the southern area. The largest known is about 3 inches in diameter." The types of Young & Bird's two editions came to the Whitby Museum, so Martin Simpson, the Curator, was in the best position to know the sf)ecimens. He is quite f)ositive that Am. redcarensis is a sulcate. The example now figured (T.A. DCVIII) is presumably that which Simpson called " Young's original Redcar specimen " — Simpson's measurements were often only approximate. If so, it will be best to accept the sulcate specimen and to call it the lectotype. Its locality would then be Redcar : Young & Bird seem to have been in the same confusion about the locality as about the specimen. Pallasiceras, Spath MS. cit. by Lamplugh, Kitchin & Pringle (Concealed Mesozoic Rocks in Kent ; Mem. Geol. Surv., 1923, p. 222) : " Pallasiceras ' pallasianum ' " and footnote 2 " Ammonites pallasianus as hitherto understood by British geologists. Dr. L. F. Spath permits us to say that, in a work now in the press (to be published by the Geological Survey of India), he proposes for this group the generic name Pallasiceras : genotype Ammonites rotundus J. Sowerby, ' Mineral Conchology,' vol. iii, pi. 293, fig. 3, 1821. The genus does not include A. pallasianus of d'Orbigny." This is the first published mention : it fixes the genotype definitely on Sowerby's specimen. Unfortunately, this is only a body-chamber fragment, much worn, and giving Httle indication of suture-hne. This holotype is figured in T. A. DXC, 1925. Topotypes show that the suture-line is short-lobed, and that the inner whorls are multicostate, somewhat of virgatite pattern, not dissimilar from those of young Lydistratites (T.A. DCVb). So far as can be at present ascertained, the difference of Pallasiceras from the prior-named Lydistratites is that in Pallasiceras the species remain comparatively small and the suture-line comparatively simple with short lobes. Pallasiceras would appear to be the phaulomorph of Lydistratites, having about the same relation to that as Otoites has to Emileia. Pallasiceras rotundum occurs in the Nodule Bed of the so-called Kimmeridge Clay of Chapmans Pool, Isle of Purbeck, Dorset (T.A. DXC) — this Nodule Bed being about fifteen feet above the shore, and 14 TYPE AMMONITES— VI Feb. quite different in date from the Kimmeridge Clay Nodule Bed of Oxfordshire. P. lydianites (T.A. DCIV) is from the Lower Portland Pebble Bed, Hartwell, near Aylesbury, Bucks. The forms figured by Dr. Neaverson (Amm. Upper Kimm. ; Geol. Dept., University of Liverpool, 1925) as Pallasiceras, from Chapmans Pool are, by the suture-lines which he has given, Lydistratites. Of those for which he has not given suture-lines it is impossible to say whether they are Pallasiceras or Lydistratites. His Pallasiceras ultimuni from Hartwell, near Aylesbury, has neither the suture-Hne of Pallasiceras nor of Lydistratites, and possibly it has no relation to either genus. No evidence of any connection is given. Lydistratites, S. Buckman, 1922, Genotype, L. lyditicus, T.A. IV, CCCLHIa. a serpenticone biphcate developed from a virgatite. The inner whorls of the holotype show traces of approximate parvicostation. The suture-line is more longilobate than that of Pallasiceras and Li, L2, increase in length with age ; ES also increases, but not so rapidly. Lydistratites lyditicus has been figured in T.A. (CCCLIHa-d) from the Pebble Bed at the base of the Portland-Stone series of Long Crendon, Bucks, from [Upper Lydite Bed of Swindon, Wilts], from Nodule Bed of Chapmans Pool, Isle of Purbeck, Dorset. Forms figured by Dr. Neaverson (Amm. Kimm. 1925), with suture-line, as Pallasiceras from Chapmans Pool belong to Lydistratites, see Pallasiceras (p. 13) . Lydistra- tites biformis and L. cunctator are figured (T.A. DCV, DCVI) from Lydite Pebble Bed of Hartwell, near Aylesbury, Bucks. HoLCOSPHiNCTES, Neaverson, (Zones of the Kimmeridgian ; Geol. Mag. Ixi, 1924, p. 149). " Holcosphinctes pallasioides gen. et sp. nov. (= Am. biplex H. B. Woodward, Middle and Upper Oolites : Metn. Geol. Surv., p. 156, fig. 72, 1895), of which specimen No. 30721 Coll. Geol. Surv. is genotype and holotype." The genus differs from Lydistratites and Pallasiceras in that its primary ribs are short, and the secondary ribs commence well on the lateral area, while in the other genera the primary ribs extend nearly to the peripheral border before bifurcating. The suture-line also differs from Pallasiceras in being more lobate and from Lydistratites in EL < Li instead of EL > Li. H. pallasioides has been figured (T.A. DLXIX) from the Crendon (Hartwell) Clay of Long Crendon, Bucks. Dr. Neaverson (Amm. Kimm., 1925) depicts H. pallasioides and H. flexicostatus (PI. in, 5, 6) from Hartwell Clay, of Hartwell, near Aylesbury, Bucks. Paravirgatites, S. Buckman, 1922, T.A., IV, CCCVIII, Genotype P. paravirgatus. Somewhat like Pallasiceras in ribbing, only that the furcation-point is much nearer the umbilical edge. The venter is well rounded off, not flattened, as in Pallasiceras. The suture-line is short- lobed, and in this respect agrees with topotypes of Pallasiceras from the Nodule Bed of Cliapmans Pool. P. paravirgatus (PI. CCCVIIIa) is from the coarse grit of the Shotover Grit Sands of Shotover, near Oxford ; that of PI. CCCVIIIb is, by matrix, from the Cemetery Beds of Swindon, Wiltshire; P. desider- atus is from Long Crendon, Bucks, among sands (Hudleston label and Collection), that is, from Thame Sands ; P. infrequens (PL DCIII) was obtained in place from the hard layers of sandrock at the top of the Thame Sands of Thame, Oxfordshire. 1926 SYSTEMATIC 15 The species figured by Dr. Neaverson as Paravirgatites kimmeridgensis (Amm. Kimm. 1925) is unlikely to be a Paravirgatites : the ribs are much too straight and regular, as may be seen by comparison with P. paravirgatus, T.A. CCCVIIIb ; but as Dr. Neaverson has given no suture-line, the right genus cannot yet be determined. Shotoverites, S. Buckman, 1925, T.A. DLXII. Like Wheatleyiies, but with decidedly shorter lobes and with more distinct tricostulation in the magnicostate stage. Shotoverites rednctus should replace Wheatley- ites rednctus (CCCLXXXIV), whose date would probably be later than W heatleyites , namely pringlei, on the evidence of S. pringlei and its locality. Kerberites. T.A. V, 1924, DXX, Genotype Kerberites kerberus. Heavy-ribbed, with, frequently, triplicate secondaries, whence the name, from the three-headed dog Kerberus. The whorl-section is obovate, that is, somewhat convergent. Specimens have been figured from [Chicksgrove, Tisbury], and from the Cockly Bed of Swindon, Wiltshire. Poor examples are known from Long Crendon (North-West pit), Bucks, which, by their matrix and the extent of quarry opened, come from about the Rubbly Limestone Bed, Behemothan 7, (T.A. IV, 1922, 26). The matri.x shows that they cannot be lower, and the extent of the quarry that they might only be a little higher. The noticeable point about the example now figured, PI. DXXa, b, (T.A. VI, 1926), is the preservation, in the inner whorls, up to a diameter of about 35 mm., of the small and close-set costate or virgatite stage. Yet there seems to be no other difference, neither in suture-line nor in plotted proportions, from the holotype (T.A. V, 1924, DXX), which has well-costate inner whorls. Either the holotype has accelerated the oncoming of magnicostation — precedentive palingenesis, or the plesiotype has retarded it unduly — cunctative palingenesis. The phenomenon of the plesiotype's inner whorls may justify two statements. First, that the magnicostate Gigantids are the descendants of multi-parvicostates — either of virgatites, in which secondary ribs are bundled into a primary, or of pectinates, in which the ribs are like those of a fine tooth-comb, only not always single, sometimes bifurcate. Second, that it is dangerous to make a distinct species, let alone a different genus, on account only of dissimilarity of the early stages, for such dissimilarity may be only the result of differential acceleration or retardation along a given line of development. The phenomenon of the inner whorls of the holotype, as well as of the inner whorls of other Gigantids, teaches that the change over from parvicostation to magnicostation in such forms could be so rapid that the parvicostate stage was practically omitted from the recapitulation : as soon as ornament began to be formed, magnicostation started. Lydistratites shows magnicostation arrived at after a virgatite stage ; Wheatleyiies exhibits magnicostation developed after a pectinate stage ; in these two cases the difference of inner whorls would justify differentia- tion into genera. Because the two forms of inner whorls are not sequent to one another ; they are parallel developments even when not strictly synchronous. Rapid acceleration of the magnicostate stage in species of either of these two genera would yield inner whorls looking very l6 ■ TYPE AMMONITES— VI Feb. 1926 unlike the prior virgatite or the pectinate respectively ; but as the magnicostate character is sequent to the respective parvicostate stages, it would not justify generic separation of magnicostates from parvi- costates. KosMOCERATES. There has now been figured a sufficient number of genera, which have hitherto come under the designation of Kosmo- ceratidae, to make possible analyses of their characters in tabular form. This is by far the most concise method of showing how genera differ one from another, and what progression or regression they make in the matter of development. This method is preferable to that of describing single genera promiscuously ; but its disadvantage is that time must elapse before a sufficient number of genera have been illustrated. The subsequent Tables III — V give analyses under the following headings : — Shape of Venter — runcinate, or subsulcate, or sulcate : these are the progressive stages — towards greater heterogeneity ; then follow reverse stages — to homogeneity or less heterogeneity — subsulcate, runcinate, rounded. Ornament of Venter — progressive — ribs, tubercles on the end of single ribs, tubercles into which there flow 2, 3, 4 or possibly more secondary ribs ; then the reverse, 4, 3, 2, i, to none, and finally to smoothness — loss of ribs. Ornament of lateral area — progressive — costate, one median row of tubercles, two rows of tubercles, one being median and the other inner marginal (umbilical) ; then the reverse — back to one row of tubercles after having had two rows, costate merely, after loss of all tubercles, and a singular development in a limited series — back to smoothness, but retaining and even enlarging the inner marginal tubercles: this is a singular phenomenon, because in most cases the rule is ' the last character to come is the first to go ' : this departs from that rule. There are other characters which might be used in analyses : strength of primary ribs, number of secondary ribs to primary- — from one to perhaps seven and back again ; and all the various details of suture- line — relative length of EL, Li, L2, characters of, say, Li from the simple trefoil or clover-leaf pattern to the long, elaborate, thin-stemmed cruciform. All such characters have to be utilized in the naming and distinguishing of genera, but their analysis is not regarded as necessary now. However, in the analyses of the characters which are made it will be obvious that there is often a difficulty in saying whether a given character is in a pre- or a post-condition : for instance, a runcinate venter is obviously post-round ; but is it pre-sulcate or post-sulcate ? Have the members of a given genus, which show a runcinate venter, been through a sulcate stage and returned to the runcinate ? Or is a runcinate venter the highest development to which they reached, so that the next move is back, to rounded again ? Ontogenetic studies may sometimes answer these questions ; but not always — for there is ever the possibility of a stage being skipped. Then runcinate pre-sulcate and runcinate post-sulcate merge one into the other. 1926 April SYSTEMATIC 17 Table III — Morphic Development — Venter (shape) c ■A ■7, X ■■J =f ■7. J •r. Si II ■■J — ' c -3 c 3 3 Kosmoceratan Kuklokosmokeras X X X Bikosmokeras X X X X ? ? ? X X Katakosmokeras X Zugokosmokeras Hopli kosmokeras Spinikosmokeras Gulielmites ? X X X X Anakosmokeras X X Reineckeian X X ? X X X Proplanulitan Sigaloceras Galilaeites X Galilaeanus X Galilaeiceras X Gulielmina Catasigaloceras Gulielmiceras X X ? Toricellites X X X Gowericeras X X X X Macrocephalitan Toricelliceras X X X Kepplerites Cerericeras X X i8 TYPE AMMONITES— VI April Table IV — Morphic Development — Venter (ornament) Ages Genera 8 o •c K to Tuberculate (2, 3, or many costa;) Tuberculate post 2, 3 or many costse) -M 6 Smooth (post- tube rculatc or post-costate) Kosmoceratan Kuklokosmokeras X X X X Bikosmokeras 2 2 4 3 2? I? Lobokosmokeras Kosmoceras Katakosmokeras Zugokosmokeras Hoplikosmokeras Spinikosmokeras Gulielmites 2, I 3,2,1 2,3.4? X X X X X X X X Anakosmokeras X Reineckeian Proplanulitan Sigaloceras Galilaeites Galilaeanus Galilaeiceras Gulielmina X ? Catasigaloceras Gulielmiceras X X X X X X X X ? Torricellites X X Gowericeras Macrocephalitan Toricelliceras Kepplerites Cerericeras 1926 SYSTEMATIC 19 Table \' — Morphic Development — Lateral Area (ornament) Ages C.enera 0 •T. 0 0 a „ a r. ct '■$ 1 ° 1" ■T. S 0 ^-^ ■2 0 0 ■r. Smooth (inner tubercles retained) Kosmoceratan Kuklokosmokeras ? X X X X X X X X X X Bikosmokeras Lobokosmokeras ? ? X Kosmoceras Katakosmokeras Zugokosmokeras Hoplikosmokeras Spinikosmokeras Gulielmites X X X X X X X X X X X X X Anakosmokeras Reineckeian X Proplanulitan Sigaloceras Galilaeites Galilaeanus ? X ' X Galilaeiceras Gulielmina Catasigaloceras Gulielmiceras X X X X p ? X Toricellites X X X X X X X X X Gowericeras Macrocephalitan Toricelliceras Kepplerites Cerericeras X X 20 TYPE AMMONITES— VI April 1926 The genera in the Tables III — V are placed approximately in chronological order, the latest above, the earliest below ; but in those cases where several genera belong to the same date, their individual order has no chronological signification. Of the others, the exact sequence is not known for certain in one or two cases, like that of Kosmoceras : its date may be a httle later, less likely any earlier. Otherwise, on the whole, the evidence for the chronology of the genera is fairly clear. They are distributed among South English strata in the following manner : — Kosmoceratan North Oxford Clays Christian Malford and Calvert Beds Reineckeian Almost no deposit Proplanulitan • • . • • • • Kellaways Rock Kellaways Clay Macrocephalitan . . . . Upper Combrash But the genera Kepplerites and Toricelliceras are unknown in England,