I^ibrarg of tbt '^nsnxm OP COMPARATIVE ZOOLOGY, AT HARVARD COllEfiE, CAMBRIDGE, MASS. J^oiinlJES 1)2 prfbate suiiscviiitfon, [n 1S61. iocrvLje/hJC- ■ iVb. 7 3 / 6 - ■0-. I I- / I POLYCYSTICS, FIGURES OF REMARKABLE FORMS &c.. IN THE AaSAOOS CSASS »s##sim (Chiefly collected by Dk. Davy, and noticed in a Lecture delivered to the Agricultural Society of Barbados, in July, 1846.) DEAWN BY MRS. BURY, As seen in her Microscope, on Slides prepared by Che. Johnson, Esq., of Lancaster, 1860 and 1861. 8BOO]Sri3 EDITION, EDITED BY M. C. COOKE. PUBLISHED BY W. WHELDON, 58, GREAT QUEEN STREET, LONDON. W.C. MCZ LIBRARY HARVARD UNIVERSITY CAMBRIDGE. MA USA NOTICE TO SECOND EDITION. The 'negatives' of this work and all interest and copyright having passed into my hands, I have, in consequence of numerous demands for copies resolved upon the reissue of the entire Avork, as originally published — so that all references and quotations heretofore made to plates, figures, or descriptions will equally apply to the present, which I trust will be found in no way inferior to the first edition. M. C. C. P O L Y C Y S T I ]^ S . PREFACE TO FIRST EDITION "But what are Polycystins" is the constant exclamation. — So little is yet known of these curious organisms that naturalists have not yet decided on their exact place. They belong however, to the sub-kingdom "Protozoa," and Mr. Reay Gi*eene in his "Manual" places them between "Rhizopoda" (of which the tyj^e is Amceba, so commonly found in fresh water as little gelatinous lumps, of the very lowest form of animal life) and Sponges, which form flinty interior skeletons, called spicules, to support the spongiose web, and the animal mass of jelly, called Sarcode, with which they are invested. The Polycystins are also masses of Sarcode, but they appear to form both internal spicular-hke supports radiating from the nucleus, and also external shells of a network of flint, through the interstices of which they are said to protrude pseudopodian threads (pei-haps analogous to the tentacles of Sea-anemones and Star-fishes or arms of Hydra) by means of which they are supposed to imbibe nourishment, and to have some powers of locomotion. A careful observation of the larval changes of the Echinoderms, and the pupae states of other young things, can make one understand how the protean forms of the Polycystins need not all designate distinct species, but that many grotesque differences of shape, and of spinous ornamentation may, in reahty belong to the same object, in different stages or under different circumstances of development, such as more or less pressure, abundance or scarcity of the siliceous material in the surrounding water, &c. Perhaps there may be said to be four classes of form : — 1st., the discoidal or planorbian flattened spheres, variously winged or bordered; 2nd., the orbicular, "with or without spines; 3rd., the vase or bell-shaped consisting often of repeated globes growing out of each other, sometimes with a re-duphcation of parts, that might seem to indicate a tendency towards increase by fission ; 4th., the plane or straight-sided forms. Dr. Wallich promises a full history of the structure and mode of development of Polycystins in his forthcoming work, having obtained living specimens in his recent deep-sea soundings : some in association with those wondrous benighted star-fishes from two miles deep. Professor Johannes Miiller fished them up frequently in the Mediterranean, near Cette and St. Tropez ; always from great depths, and under very clear pure sea-water, but from their great delicacy it was most difficult to obtain really living subjects, as even the passing through the water, in hauling up the apparatus used in dredging them caused death, and when that occurred the pseudopodia immediately collapsed, the sarcode substance became flaccid, and little more of the vital economy of the organisms could be observed. The late Professor W. J. Bailey also records some specimens as occurring among his deep-sea soundings in the Sea of Kamschatka ; he speaks of their "organic contents" but does not state whether obtained in a living state. In the stomachs of the Salpaj, which form so large a portion of the food of whales, shoals of Polycystins are found, which have in their turn served as food to the Salpaj. In a fossil state Polycystins have heen found in many parts of the world ; those figured in the accompanying Monograph, are fi-om a sort of chalky earth found in various locahties in Barbados, where Sir Robert Schomburgk describes it as having been forced up by volcanic action, through the coral reefs of which the island is formed, from the deep bottom of some ancient ocean, where countless ages ago they may have enjoyed their gift of the power of abstracting pure Silex from the water, and, while in a plastic state, weaving it into their elegant glass corslets, — then lajdno- down their skeletons to form part of that incalculably vast bed of ocean-deposits, of which some infinitesimally small fraction occasionally comes under the microscopic ken of man, ^to shew us how the minutest and humblest atoms have yet their allotted par.t in fulfilling the Laws of the Great Creator. Professor Ehrenberg, in a discourse delivered before the Berlin Royal Academy of Sciences, says, speaking of these fossils from the rocks of Barbados (which he calls Siliceous Polygastrica) "for these organisms constitute part of a chain which, though in the individual link it be microscopic, yet in the mass is a mighty one, connecting the Life-phenomena of distant ages of the earth, and proving that the dawn of organic nature co-existent with us, reaches farther back in the history of the earth than had hitherto been suspected. The microscopic organisms are very inferior in individual energy to lions and elephants, but in their united influences they are far more important than all these animals." Professor Owen (in his "Palasontology," 1862,) further remai-ks "if it ever be permitted to man to penetrate the mystery which enshrouds the origin of organic force in the wide-spread mud beds of fresh and salt waters, it will be, most probably, by experiment and observation on the atoms which manifest the shnplest conditions of life." P. S. B. Croft Lodge, Januain), 1862. .7^ 'fKcyZ^.^^ 7 //'- ^ ^«zi '/>. A PLATE I. na. 1 & 6. — Varieties of EucjTtidium Acuminatum of Ehrenberg. 5. — Podooyrtis Schomburgkii. Ehrenberg. 2, 3, 4. — Varieties of the same. USA PLATE II. FIG. 1. — Stylodictja yracilis. Ehrenberg. 2.— A Dictyospiris (?) of Elirenberg, highly developed in slide Zjf Cambridge, Barbados. 3. — Dictyospiris (?) or perhaps Petalospiris (?) May they not possibly be the same organisms in ditterent states of development ? Ceratospiris, (Mikrogeologie, PI. XXTT, fig. 37,) also resembles these shapes which occur in great variety in the Barbados deposits. 4. — Rhabdolithes pipa. spined stem var. Ehrenberg places Rhabdo- litlies in the family of Geolithen. 5. — Stephanolithes nodosa. ; also a Geolithen of Ehrenberg. 6. — Acanthodesmia of J. Miiller (INIittelmeeres, p. 30) Stephanolithes spinescens (?) of Ehrenberg. It occurs in double and single circlets, and witli \arj-iug number of spines in the Barbados deposits. JG2 f,-.A USA PLATE III. ria. 1. — A Polycystinous nucleus, with one spine running through it, and attached at eaeli end to a plain circle of Silex. — (In slide P>. TV. Camliridge, Barbados) Lithocircus, Mesoceua (V) 2. — A similar nucleus with four Acanthometrum-shaped spines (see Mnller's Mittelmeeres, &c., PI. X.) attached to it, the hooks of wliicli describe part of a circle. Actiniscus (?) in slide T. Cam- bridge, Barbados. 3. — A Hyaline wand, sjiirally twisted. 4 — ^Rhabdolithes pipa. var. Ehrenberg. 2':TY. PLATE IV. FIG. _,, , 1.— Stephanastrum sp. Ehrenherg. 2.— Astromma Aristoteles. Ehi-enberg. 3._St,ylosphrera sp. Ehrenberg. 4. — Haliomma with four spiues. 5._Lychnocainum faloiferum. Ehrenberg. 6._Stylospha3ra, var. (?) mth outer web (?) ©Ai-'i ■.\\0 GE. M^ USA PLATE V. KO. 1. — Astromma (?) finely developed with part of outer web adheiing between the arras. 2. — Eucyrtidiuni MongoLfieri. Ehrenberg. S. — ^Podocyi-tis mitra. Ehrenberg. 4. — A state of Rhopalocaniiuu (?) 5. — Pterocodon campana. Ehrenberg. 6. — an Astromma partially developed (?) K.. ITY ■' ' ._-.,r,'-C twlA US A PLATE VI. alocauiu: 6.— Spicidf of— (?) no. 1, 2, 3, -1, u. — Rhopalociuiiuni ornatum in different states. PLATE YU. no. 1 & 2.— Suiirella (?) from Cambridge, Barbados. Fig. 1 possibly a younii', leas developed, form of lig. 2. The slide from which the fi"-. 2 was drawn was returned to Mr. Johnson, and by him sent tx) IMr. Rails. Professor W. C. Williamson saw it when in Mrs. Bury's hands (October, I860,) and kindly suggested it might possibly lie a Surirella. 3 & 4. — Varieties of Dictyospiris (?) Ehrenberg. 5. Actiniscus (?) of Ehrenberg and Pritchard ; a triangular net, like a Diotyocha, but wth a " solid centre," which centre (or nucleus) gives the idea of being capable of stretching up into a Podo- cyrtis-like form ; sides of triangle measure .0065 ; there are nine outer and six inner cells, arranged rouud a solid-lobed and pmictured nucleus, which bears one long and two short spines. 6. — A Desmidia-like, but silicious, clear, transparent plate, with wa^•ed edges, and a perforated centre. Appears to resemble in some degree, Lithodesmium undulatum, of Ehronberg's "Kroide- biidung," page 76. Dr. Wallich suggested (from sketch) that it might be a part only of some polycystinous form. "7. ^Tlie uppei' part like Ehrenberg's Podocyrtis cothurnata, but with a tubulous prolongation of the base. th^u^^'l"-^^- ■, USA PLATE Vni. I'IG. 1, 2, 3, & 4. — Varieties of Haliomma. Ilaliomma Ilumboldtii (?) of Ehrenberg, from Cambridge, Barbados, numerous and variable. Altlioiigli there are sometimes indications of spines radiating from the centre, as in Stylodictya, yet the points romid tlie ed<^e apjiear to be merely "marginal aiipendages." — Diameters, in- cluding spines, from .0077 to .0085. 5, & 0, — Miiller describes these as stages of growth oi the Haliomma, where the outer web is spiiming itself over and ror.nd the central nucleus, and the siliceous rafters or supports extending like a framework from the micleus to the exterior covering. (Page 21 of "Thalassicollen Polycystineu, «&c., des Mittelmeeres.") 7 & 8. — Spines or Spicules in Barbados deposit. 03 n ;.1A USA PLATE IX. Fit). 1.— Petalosi^iris foveolata— var. Ehr., (INIikrogeologie, Taf. XXXIV, 14.) .0075 high, spiues iiiduded, .0031 dia. of ball. 2. — The same without the central spike through it. 3. — A Podocyrtis (?) of Ehreuberg. 4.— A Podocyrtis (?) nearly akin to Podocyrtis Mglea. (JVIik. Taf. XXXV. B. IS); measures .0106 high, .0052 broad. 5. — A Podocyrtis (?) without the usual surmountmg spme. 6. — A Lilliomelissa (?) These beautifid little shapes, like cry.stal tea- pots or coflee-pots, for some primeval world's Queen Mah, are frequent in the Barbados deposit. ITY ;sA PLATE X. PIU l.J-Transparent cross, with tubular canals running through the arms and united by a central ring, — a structure resembling an object fio-ured in Professor W. J. Bailey's "Microscopic forms in the Sea of Kamschatka," under the name " Spongolithes orthogona," but which he says he has referred with some hesitation to Spongolithis. Measures .01125 high, .008 broad, with a slightly warted or rugose surface. 2. All Eucyrtidium form bearing tubular spinous projections, arranged in the pattern of the perforations m Eucyrtidium elegans; appears to be enclosed in a transparent egg-shaped sheath or envelope, .00362 long — Lithobotrys adspersa, Ehr. Mik. Taf. XXXVI, fit;. 5, has the appearance of a wing or fin extending, round the object in a somewhat similar way, and so iius 'Jarpo- canium solitarium, Taf. XXII, fig. 28. This specimen is in iSlide No. 611 Springfield, Barbados. g. Eucyrtidium (?) elegans, in an imconstricted state, .004 long, .0012 broad • 2-3 rows of nearly equi-distant perforations ; from Chim- borazo, Barbados. 4._APodocvrtis (?) mitraor iiapalis, var. (?) the lower part devoid of perforations, and with a thickening of the silex round the boundary of the plam part, — two spines from the apex. 5._Fodocyrtis'papalis, Ehr. Mik. XXXVI, 23, .00687 high, .00375 broad. In numerous specimens the outline of the base varies considerably, Ijut there always appears to be an internal ring or ledge. .-,Y iTY PLATE XL no. 1 . — A magnificent Polycystin, from Cambridge, Barbados. It measures .0214 in heiglit, viz., the ball .0028, and .0186 from the ball to the base, where several more squares appear to have been broken off, — about 18 to 20 rows of squares, like windows ; inside some of them a very fine internal network is seen ; througli others appear a faint reflection of the bars on the opjjosite side of the oljject: the effect of this, viewed Lii the Binocular (half-inch objective) is very striking. 2. — Eucyrtidium tubulons, Ehr., measures .01 feet long, .0028 broad, from Peak of Teneriffe, Barbados. Quarter-inch objective. 3. — Stylosphnera (?) Ehr., measures .01 high, curiously beset with sharp, spear-like spines, and covered apparently \\dth pointed linobs or warts. Some of the Barbados Polycystins suggest an idea as if their perforations either may have been, or miglit have become occupied by these sort of projections, which, when broken off, leave holes, and being hollow, would still permit the protrusion of the so-called Psendopodian threads, which Professor J. Miiller says "one may conjecture (Vermutheny to be the means by which the Polycystins imbibe nourishment, although their con- nexion with the Sarcode substance of the bodies, requires more clear elucidation. In the TliallassicoUen and Polycystina, they can only be traced as far as the skin-like capsule of the flabby jjart lying under the flint corselet. 4. — Dictyospiris (?) jirobably the same object as fig. 2, on plate II > turned on the reverse side. Ehrenberg calls this "Ruckseite,' and the other with the larger openings, "Mouthside," — from Cambridge, Barbados. 5.— Spongolithis acicularis, (Mik. Taf. XXXVI, fig. 47) a Pliytohtharien of Ehrenberg. 6. — Amphidiscus verticillatus, Mik. Taf. XXXVI, fig. 45, classed by Ehrenberg as " Phytolitharia," — of plant growth. USA PLATE XII. rio. 1. — A spinous variety of EucjTtidiiun ampiillus (?) the narrow end prolonged into a tubiilous spine, — diam. of Ijulb, .00275. Chimborazo, Barbados. 2. — ^Podocyrtis (?) whole height, .0112; breadth, 0055 ; height of cupola, .0027. Professor J. Sliiller says " in aU the flask and beU-shaped Polycystins, the first joint (glied) of the reticulation begins from the top, and the number of the increasing links progresses with growth in a definite ratio." The links of the lower part in this fossil skeleton seem rimning into each other irregularly, like dropped stitches in a stocking, or bursting bubbles in a gelati- nous film while solidifying. 3. — A further variation of Podocyrtis Schomburgkii, as shewn on plate I, fig. 3. 4. — A modificatiou of fig. 2, on plate I. 6 & 6.- — Tlie reticulations progressing further towards the "iarfrfe/," or Lattice-shape. In tig. 6, the inner net is very plainly seen, its reticulations are also scpiare, with (juarter-inch magnifying power used, about 470 linear. Springfield, Barbados. In ano- ther slide is a broken-oft' top of one of these Ladder-Pyramids, with the narrow neck swelling out into the surmounting ball nucleus (?) r.' MA USA PLATE Xin. FIG. 1 & 2. — Front and side view of a globose, slightly conical body, pretty regularly areolated, and surrounded by a rounded honeycombed riflg. I am indebted to Dr. Greville for poiiiting out the front view, as belonging to the same object, which he decided^ to be "not a Diatom." Can it belong to Stephanopyxis or Xantho- pyxis or some of that obscure group which even Ehrenberg regards as " very doubtful Diatoms ? " See Pritchard, page 827. Itls a very beautiful object, but difficult to get a good view of, as the ring and the globe require different foci. In slide, Vaughan's'Barbados, No. 1 ; magnified about 400 diameters. 3.— Probably a variety of the Dictyospiris on Plate II, fig. 2, and Plate XI, fig. 4, but with a greater number of spines, and differently arranged. 4. — Possibly a Lychnocanium, with the apex dilated into a broad flat spatula instead of the usual spine. 5.— A Rhabdolithes (?) , 6.— A partially developed form spinning its outer web roimd the nucleus, as in Miiller's description of Halionima. 1. — Chinese lantern shape in slide. Vaughan's resembles Dictyolithes PjTamidalis of Mik., PI. XX. fig. 30; but this is a much more developed specimen. aX PLATE XIV. FIG. 1. — Astromma (?) A rhomboidal shaped mass of a very confused sponge-like web of fine tangled threads ; inclosing in the middle a dark areolated ball. Four sharp spines protrude from the web at right angles, and measure from point to point •01714. 2, 3, 4. — Varieties of Astromma Aristoteles (?) 5. — A more complete specimen of Rhopalastriun lagenosum. Mik. PL XXII, fig. 22. 6.- Central part of a similar organism. These beautiful crosses, with. and without balls or spuies at the ends of the arms, are very frequent in the deposit from Mt. IliUaby, Barbados. For the selected slides of that material from which the figm-es m this and the following plate are chiefly drawn, I am indebted to Geo Mansfield Browne Esq. ' ' ' ' ' ■ ^pfej&f .«--fcT:»v >-*;'." V. ^H ;^g^^H jii ..^ ^ Klii |Bf: f^l . %y ' /I WA siv c ^ ^S^ f ."^^s^- 1 m m 0^' twi '1 ^L V -" • ■ ^jf^'' - m niitifiijg'- ■ v!^ ^ Si^m i ■'Mm ^ ^ ^^ 1* '^v^5^i^^ 4fTV^ \ "^ oi ^>o,_ - 5 '.t ^V ' > ^^^m • M^$ K^ f "-'PP-^i fyjK"-. -r ' IP^^ ' 1 JS^^ ''' ^tt & - 1 ■ /^^l '^^ M .ll» # i ^ : ?vrp- ■- ■ - ■ ' -;ty PLATE XV. FIG. 1, 2, 3, 4, 5, 6, 1. — Various curious forms of three-winged Astrommas (?) Stephanastrum, or some allied shapes. Fig. 3 has a partial representative in Ehrenberg's Hynieniastrum Pythagora?, Mik. PI. XXXVI, fig. 31. In fig. 1 the three arms appear to be hollow tubes of a sort of honeycomb : the extreme measurement, .0211. The very remarkable border or edge to the sponge-like webwork, is the nearest approach I have ever seen to the rhombic frame (separated from the web) of the " Stephanas- trum Pthombus" shewn on PL XXXVI of Mkrogeologie, fig. 33, and copied into so many works. 8.— A delicately ornamented spicule (?) with still a small portion of web adhering to it. AU these objects are from Mr. Browne's slides. ■TY ■ A USA PLATE XVI. no. 1. — A short hollow cylinder with large perforations, and ornamented with little pillars. In slide South Naparima, Trinidad, No. 5. •2 & 3. — Globular bodies with 2, or 3, or 4, pipe-like openings, the markings on them very irregular in size and distribution, and appear more like warts, or slight depressions, than actual pimc- tures. Measure of diam. of bulb, about .00137. From South Naparima, Trinidad, No. 5. 4. — Obehsk pillar ; resembles Professor Bailey's Rhizosolenia hebetata, which he found in Kamtskatka. This specimen is from Barbados. 5. — Two extraordinary long spines fixed by their smaU and branched ends to a very beautifiil oval disk. Apparently the centre or axis of some large Polycystiu in slide Barbados, No. lOOJ^, measures from the centre to the point of one spine, .0228. Drawn as seen with half-inch objective. 6. — An elegant little transparent plate, without any perforations — a pretty crenate edge. In shde South Naparima, No. 2. 7. — A Haliomma (?) long, egg-shaped, very spinous and rough. Springfield, Barbados. 8. — The outer margin or circlet of Haliomma Humboldtii, shewing the points as extensions of the outer sUiceous coat, and not attached to the radial spines or rafters. PLATE XVn. riG. 1. — Lithornithium Hirimdo of Ehrenberg, Mik., PL XIX, fig. 53, but this is a much finer and more perfect specimen ; frequent in the Barbados deposit : size very variable. 2. — A broad and stunted variety of Podocyrtis Schomburgkii. Mik., PI. XXXVI, fig. 22. 3. — Podocyrtis (?) with five spined or serrated legs : body and sur- mounting spine all very irregularly foraminated. Measures .00462 high, .00325 wide. Barbados, slide No. 38. 4. — A Dictyospiris exhibiting the very curious bulbous terminations of the spines assummg a cellulate (?) appearance. 5. — ^A very regularly aerolated small hollow cone, frequent in the South Naparima, Trinidad slides. Cornutella profundis Ehr. 6. — ^Petalo.spii-is diaboliscus — Mik., PI. XXXVI, fig. 12 — variety, with the lower spines prolonged and forked at the ends. 1. — Variety of Rhopalocanium (?) S. — Another state of Rhopalocanium, with the wing-like membranes stiU attached to the body, and roughened with irregidar wrinkles. TY PLATE x\an. 1 . — A rough spongelike-looking ball with, strong spines. 2. — Spongolithis (?) a spicule. 3. — A state of a Haliomma — strong spokes from central nucleus to circumference, at imequal distances — some network apparently spimiing partly over one side, according to MiiUer's description. 4. — Spongolithis anchor a of Ehrenberg — A spicule. 5. — Spongolithis ramosa, Ehr. 6. — Serpent-like form — very frequent and variaOle in the Barbados deposit. "7. — Lithasteriscus reniformis. Ehr., '■'■Nord and Stid Amerika" Taf. VI. fig. 35. / think all these bean-like forms are wartedor rough- ened on the surface, not truly foraminated. 8. — An irregular three-lobed transparent Plate from Chimborazo, Bar- bados, analogous to fig. 6 on PL VII. Dr. Wallich says these are parts of an organism constituting a new genus intermediate between Sponges and Polycystins ; this plate, forming part of the outer siliceous skeleton, the interior being filled with free spicules. The ovals, Nos. 1 and 2, on Pi. 7, (of whicli many more examples have since been found) are plates instead of spicules, taking the place of an internal skeleton of a kind of organism of which no perfect specimen has yet been found; and which is also iutemiediate between Sponges and Polycystins. 9. — Spongolithis aspera. SA PLATE XIX. FIQ. 1. — 9. — Probably varieties of the same species of Polycystin in the Barbados deposit. They frequently assume a triangular ap- pearance, there are no wide external openings visible, — but Dr. Wallich has detected small 0})enings, which he compares to a "Cat's claw," at the roots of the spines. ">a£x 4 t'^\ ♦'5*. - ;^!SC: V J:^'3frr ^ ^t:^ \ ^^^■Ko f^y^^l ■^fl^ ^^^Vv^ <^HE^^^^I I^^IrH B^^i^^B B&l^oool^^ ^V^^^^^ll^^o T. ^ '^^~' ^^^^5 ^^wiJf^o^ ^ <^ ^^o^^K V • 4^ ^^^^^ ^■^n^^^'^yi^B % / ^^^^^^^I^^^Bpj^^^^^^ O 0 .^^^^^^^^^^^^^1 # V /l4 i^- f \« * <^-^ V i Jilk ^^^KsJ^H 'f Jfefe- ^KJ^O^O^^« ^^^^^H&o^l^^^^^H V^^^SBbj^" ^4 ^^^■^I^^He 0 0 Qo|r^H '^gKj. ^ ^ '*w ' *" T*''*^^ ' ija^^ ^K^B 0 0 0 o9^ / iM^KAi 7\ ^^^mS^^a<< 1 •42^>-^'^---^K^, ^^Xij^^X^jyj^l^^ I^Hwoo . \ i ^^ /, ^ .^^■MBoop^ Nr\ ^ ' .'^- .^KFT, > \^^ . W" ^^^^K? ^ ^'^^l ^^' 4 ■ /l \ \ ^Hk? ^ ^^^^^^1 -i^ \ *.¥ ♦2l: "i ^^■■bO !-> >r f-faH^^^H ai ^^^^^>^^«^' ^'*3' -'.TY 3A PLATE XX. FIG. 1. — A five-sided Steiihanastrum, with a remarkable resemblance in shape to a Cushion-star (Goniaster), being raised in the centre gradually from the edges. Measures from angle to angle .0148, from Chimborazo, Barbados. Dr. Davy. 2. — A Haliomma, which Dr. Wallieh says "started in life with the intention of being two spiued," met with obstructions, and sub- sided into this form. 3.— A three-limbed Astromma. — ^For this specimen I am indebted to Dr. Greville. Atlantic Ocean soimdings, 2360 fathoms deep. Lat. 45.41 north: Long. 16.29 west. 4. — Curious appearance of a twin or double-bodied Polycystiu. 5. — Rhabdolithes of Ehrenberg, with the pipe stem curved into a circle, and spined. 0. — A beautiful lamp-shaped Podocyrtis, or possibly a variety of Rhopalocauium of Ehrenberg, not fully developed. . ZITY A USA PLATE XXI. FIG. 1. — A transparent flat branch — with canals, but no perforations — as seen with half-inch objective: in .slide, Chimborazo, No. 4. 2. — ^A six-sided cushion, still a Stephauastrum. 3. — Stylosphoera of Ehrenberg; rather dwarfed, and one spiue become bifid. 4. — Many-spined Haliomma? 5. — ^A Polycystin, not unfrequent in Barbados earth. 6. — A massive beautiful spine, looks as if it might have been the central support of some organism. 7. — Again one of these Plate-spicules — of what? Dr. GreviUe sug- gested, July, 1863, that it might probably be Actiniscus stella; Professor Bailey considered Actiniscus as a Polycystin. 8. — A fenestrated Pyramid, possibly a Podocyi'tis ; similar to figs. 5 and 6 on plate 12, but with this remarkable difference, that the bars, or network of silex bounding the window-like openings, appear to be very finely perforated or cellulated. Dr. Wallich examined this specimen, and considered that the roughened, or apparently cellular appearance, might have arisen from a diseased state of the sarcode while depositing the siliceous bars. I have noticed the same appearance on parts of other specimens, and on spines which have become bulbous at the ends. No inner web discernible through these windows. 9 & 10. — Beautiful little siliceous stars. Cambridge, Barbados. 1 1. — An extraordinary silicified east of the septal lines and primordial segment, with part of the interior of a Textilaria ; in a slide from Springfield, Barbados. Dr. Da\-y. That the original carbonate is changed to silex is proved, not only by its having resisted the treatment with strong acids and alkalis used in preparing the Barbados earths lor the microscope, but also that no colour was shewn vmder the strong Polarizing apparatus of po^^•eJ■ful microscopes ; and the process of such a change is perfectly ex- plamed by Professor Ehrenberg's account of the infiltration of siUcate of iron into some of the Foraminifera, gi\ing thus per- fectly preserved casts of the inside of the shells*; this specimen measures .0131 iu length. *Note. "Ueber don Grun.sand, uiid seine; Erlautcrung." Berlin, 18-56. TY PLATE XXII. FIG. 1. — Haliomma, shewing traces of tlie Sarcode. 2. — Haliomma, with strong thorny spines. 3. — Eucp-ticlium, with shell much thickened. 4. — Tlie inside portion of Ehrenberg's Stephanastrum rhombus, with the investing web, and the edge or border broken aw^ay, or be- come obsolete. Many examples of this in Mr. Mansfield Browne's Barbados slides. 5 & 6. — Varieties of Rhabdolithes spectrum of Ehrenberg. 7. — Probably an arm of a Stephanastrum. 8. — An elongated variety of Eucyi'tidium tubulus, or Eucyrtidium elegans of Ehrenberg. TY .A PLATE XXIII. FIQ. 1. — A Stephanastruni, with the four ceutral arms similar to those of Stephanastriim rhombus of Ehrenberg, enveloped in a circular spongiose web, beyond which extends an irregularly-spiuous transparent siliceous border, which also extends round the ends of the arms. I think this round web is the normal form of the Stephanastrums and Khopalastrums, and the key to all the curious 3, 4, 5, and 6-sided cushions; the number of arms deciding the number of sides, and stretching out the web in the course of growth into the various shapes as long as it remains attached to them; in slide "Chimborazo Barbados Rd," size .0228. 2. — Resembles Placolithes radiata. Mikrogeologie PL XXXIV, fig. 5. There are two valves, the upper one plaited like a fan. I have since seen a broken specimen, in which the plaits appear like tubes, hollow, hke the beautiful raised i-ibs on the African Car- dium costatum. Dr. Wallich confirmed the notion of the fan-like plaits, by detecting a crack across one of them. 3. — A lovely transparent cross, with doubly trifid ends, possibly a sponge spicule; in form most nearly resembling some of the spicules of Hyalonema mirabilis, on Taf. III. of Professor Max Schultze's " Beitrage," &c. 4. — A transparent Plate, irregularly three-lobed, each lobe bifurcate, in slide "S.P. Barbados." Material from Dr. Kingsley. It appears to be of the nature of those " Hex-radiate plate-spicules " depicted by Dr. Bowerbank as from a " EuplecteUa." 5. — All explanation of mode of growth of fig. 5 on PI. VII. A Dicty- ochus net ? 6. — ^A Rhabdolithes, giving a curious example of the way the siliceous outshooting sjiines seem to go wandering on wherever tliey find the least obstruction ; at ' a ' there seems to have been an intended change of course, checked. The extreme fiexibility of these spines might lead to .a supposition whether there might not be combined with the silex in their composition some por- tion of the keratede (or horny matter) stated by Dr. Bowerbank to enter into the formation of even the siliceous coating of the spines. 7. A double circlet of Acanthodesmia of Miiller. A single circlet is given on PI. II, fig. 6. Barbados earth. !TY PLATE XXIV. no. 1. — A magnificent spicule, probably of some unknown sponge; but as, on careful examination of the beautiful figures of Dr. Bowerbank and Professor Max Schultze (kindly lent by Dr. Gray) none appear identical, it is introduced here to exemplify its approach in character to some of the Polycystip spines (or sjjicules) in slide 48. Chimborazo, Barbados. Dr. Davy. 2 & 3. — Polyeystins, the whole of whose siliceous shells appear to be running out into spines, simulating, or asserting, their relation- ship to sponge-spicules. Barbados. 4. — A broken s])ine of a Polycystin ? highly magnified, shewing the construction, and that the fine tliorn-like " secondary spicules " are really points of support for, or commencements of, the sili- ceous net-work of the shell. Barbados slide, 102. 5. — ^Three similar spines in situ, with their enveloping net-work, so far broken away as to shew the thorny spikes near their centre of junction — with half-inch. Barbados slide, 108. 6. — Sis long slender spmes, proceeding from a radial axis, and becoming roughened with little thorny spines at about half-way from the centre, and then tapering to fine points. Barbados slide, 108. 7. — A variety of Stephanolithis nodosa of Ehrenberg. Mikrogeologie ; PI. XXXVI, figs. 57, 58; slide V. Cambridge, Barbados. PLATE XXV. FIG. 1, 2. — Biddulphia sp. 3 to 9. — Hemiaulis sp., from CaiiibriJgo, Barbados. T355LO^; J'lv UAciiA"l.iA\\v> J9ni.'ii'^ Ivm KV ^iililllllllHlillllMlilillll