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PO ind ) " . gic popededteriny jroo gh rey . be lbebe pei i yo posed joa pod 1 - il 28 ; 2 - - 2 29 = 2 3 5 29 1 _ ~ 1 30 1 2 3 6 30 5 - - 5 31 Sa Sees ata ee 2 = ere 32 Dh ID Shes V7 32 : La 33 Se slime Seriey | 919 ee ae an reerese 34 AUTRE ROG ee a oe eed. 35 9 30 4 39 35 5 alts: 1 2 21 36 3 wi 79 Ss 79 36 SG - 5 21 37 Si Eel an) fat at 15 au ore yy Sere ieee 38 Wei, 1) S178 oe ee puatr veweis 40 - 235 1 236 40 > 13 26 28 67 41 . 294 1 296 41 16 yl Ba 104 42 - 254 1 255 42 5 Hil 31 1138 43 - 195 - 195 43 i 87 23 aly 44 - 159 - 159 44 1 109 16 126 45 - 116 - 116 45 3 168 18 189 46 = 72 1 73 46 - 168 10 178 47 = 41 1 492 47 : 186 3 189 48 - 19 1 20 48 - 178 5 183 49 - ils 1 14 49 - 175 4 179 50 - 4 ~ 4 50 - 140 1 141 oT - 2 2 4 51 - 132 2 134 52 - 1 - ] 52 - 104 1 105 53 — 2 1 3 53 - 86 - 86 54 - ~ — - 54 - 60 - 60 55 = 1 - 1 55 - 62 62 56 - - - - 56 - 32 - 32 57 - 1 1 2 57 = 28 - 28 —_ —- — 58 - 19 - 19 Totals 238 2078 45 2146 59 - a - 7 60 ~ 7 ~ 7 61 - 5 = 5 62 - 6 - 6 63 - 3 - 3 64 - 2 - 2 65 é y 4 - 4 didi Vis = tee 1 ~ 1 Totals 184 1941 240 2365 76 NOTES ON A FISHING VOYAGE TO THE in this region at least the plaice lives in the presence of a serious natural enemy (or enemies, for though the food of the seals in the Barents Sea has not yet been sufficiently studied, the possibility of their preying upon plaice is by no means precluded). It may perhaps seem possible that, owing to the novelty of this phenomenon, the fishermen would be inclined specially to select these damaged fish for my benefit, thus exaggerating their occurrence. I am confident that this is not the case, as the men were not even aware that these fish were being in any way regarded. THE COMPOSITION OF THE CATCH. The length frequencies of 2146 females and 2365 males, representing over three tons of fish, are shown in Table I above, each sex being sub- divided, according to maturity. The measurements, arranged in 2 cm. groups, are further displayed in diagrams (pages 78 and 79). Care was taken to secure as fair a sample as possible of each catch dealt with. That this object was attained appears evident from the slight variations in the average sizes at the twenty-nine stations. For the males, of which the averages vary between the narrow limits of 40°4 cm. and 41°9 cm., a total average size of 40:7 cm. is obtained; m the case of the females, as might be expected, a greater range in the average sizes occurs: 45°3 em.—48°9 ¢.m., with one exception, 50°5 em, (in the smallest sample taken). The total average size of 2365 female fish is 46°7 em. The population consisted almost entirely of large mature fish, the total range of size being for males 24 cm. to 57 em, and for females 24 em. to 73 cm. In Table II below the measurements for each sex are summarized in 5 em. groups, the percentage of males in each being also presented. Taste II.—Showiny the measurements of Barents Sea plaice summarized tn 5 em. groups, the percentage of males in each group being presented below :— Om. <30 30-34 35-89 40-44 45-49 50-54 55-59 60+ Total. 3 f 79 634 1141 265 12 3 - 2146 ? . Lvs 53 157 527 918 526 148 28 2365 Totals 20 182 791 1668 1188 #588 151 28 451% °% of Males. 60. 60 80 68 22 2 a) a 47 The striking feature of this table is the great proportion of males in each group up to 40-44 cm., and the subsequent rapid decrease. The male plaice is generally recognised as being a constitutionally smaller fish than the female, and would not be expected to attain to BARENTS SEA IN AUGUST, 1907. CL the same length, but at the same time the rapid decrease after 44 cm., and virtual disappearance after 49 cm., is surprising. In this recently spawned shoal the usual earlier maturity of the sex* would account for the great numbers of males in the smaller groups; for instance, in the 35-39 em. group 96 per cent of the males were mature, in contrast to only 11 per cent of the females. To only a small extent would this account for the high percentage of males being maintained in the next group, as only 8 per cent of the females now remain immature. We must look for some other explanation, which seems to me to le in the probable infinitesimal annual growth which the males now undergo. The fishes of this sex are now some 10 or more centimetres above the size I have estimated for first maturity, after which stage in life considerable retardation of growth takes place:+ It is probable, therefore, that in these slow growing plaice (see p. 84) of the Barents Sea many year groups are comprised in this arbitrary 40-44 cm. group. It is probable, too, that the rapid diminution in numbers and final disappearance of males in the succeeding groups is accentuated by an earlier mortality of the sex here, as in the North Sea.{ Looking at the curves of length frequencies it will be seen that the curve for the males does fall more rapidly from its mode or maximum height (at 41 em.) than does that for the females from its mode (at 47 cm.). The variation in the proportion of the sexes at individual stations and groups of stations, as possibly giving a clue to migrations, is dealt with later (p. 87). The curves of length frequencies (Figs. 1 and 2) in the case of both sexes, display remarkable regularity, representing an absolutely intact stock of mature plaice, such as is to be found in no other region of the world at present fished. A series of annual observations, tracing the inevitable reduction of this stock by the influence of man, and a contemporary study of this fishery’s statistics in their modern im- proved form, will throw interesting and valuable light on the changing aspects of a plaice fishery. Icelandic waters cannot now afford similar opportunities, for in the comparatively few years this region has been exploited for plaice a marked reduction of the original stock is observed by the fishermen to have occurred. * Fuiton. Twentieth Annual Report Fishery Board for Scotland, Part III, pp. 354- 60 (1902). Waiace. Preliminary Investigations on the Age and Growth-Rate of Plaice. North Sea Investigation Committee, Report 2. Southern Area, 1902-3. Cd. 2670 (1905), pp. 218, ete. + WALLACE. Report on the Age and Growth-Rate of Plaice in the Southern North Sea. North Sea Investigation Committee. Second Report (Southern Area), 1904-5, Part I, p- 33; + Watuace. Loc, cit., p. 34. MALES, 43 CAY sh ce SR OG ST 7 FISH FISH 36 5 SSeS i} 3° Sh Ty sy st LS) Sie SSeS SEOMLO MEO RES Chr 2 Sh Seas) Sosy SS Se SoS ee i SL Re IN SUS a tO PIR Ginn ON craigata Ss 2S roy a) tS hs ae he Pa eqn t= OPE ORM INKS, Uy aR my Zauaeee ys Yer Doe Urn Late cba emlly Mer iees ls Ieee Ghow Od we Tn Os AG ie GN GUT GE Ot ONfS ESS SS SS SS SS IMMATURE FISH FISH. MATURE Barents Sea, August, 1907. plaice. 25 27 29 3I Fic, 1.—Showing the length frequencies in 2 cm. groups of 2,101 male FEMALES. 435.45 47 49. Sh 53 360 ee = a 350 340 - 330 Phi call 01 oS a a mf | fpf zo = a eae oh HH -HE HH 4 a os 270 er ee | = -}- ee ee, Prem ie ee s Hf tf eles | Oe | iMG a Pann pp Seas be eS so I I mf ttf [a en rae “tftp | a2 a ae eal le es le ea ey a ie pp He | ie Ae eeeclie | /40 bal 130 Jae Pile oe aa a en feels i pela hk ie heels ie Ni | ous Ae oe ale <4 25 27 PeMginGrUGGm Giles NIG) G7 GS S/n ZaGIM FE) EU NCR ST EI L SEM ed) tr) ee te agri! SH) M x¥—%——% IMMATURE FISH. VERTICAL LINE (M) AVERAGE SIZE tee MATURE FISH AT FIRST MATURITY. Fro. 2.—Showing the length frequencies in 2 cm. groups of 2,125 female plaice. Barents Sea, August, 1907. 80 NOTES ON A FISHING VOYAGE TO THE MATURITY EXAMINATION. Owing to the method of gutting and the recent completion of the spawning season, examination of maturity was greatly facilitated. Before each fish was measured, the sex was determined by an inspection of the reproductive organs simultaneously with an observa- tion of the condition, whether immature, mature (i. spent), or doubtful. The stage “spent” could generally be readily distinguished in the females, as it was possible to press out greater or less quantities of dead eggs from the ovary. The characteristic flaccid appearance of this organ afforded an additional criterion. Quite distinct were the taut, translucent ovaries of the immature specimens. Milt still flowed freely from the majority of the males, and definitely immature fish were of very rare occurrence throughout the voyage, as is also the case in the spawning shoals of the North Sea. These were to be distinguished by the testis appearing a mere thin band, at this time contrasting with the condition of the recently spawned individuals. However, in order that errors of observation might be avoided, a special record was kept of every fish of which the condition was in any way open to doubt. Into this class were placed those fish of either sex which on further trial failed to show the presence of sexual products, and yet seemed to differ from those which were definitely immature. Facilities were not available, nor is the deck of a trawler an ideal spot for making the minutest examinations, but it is evident that the main results are not seriously affected, as the size at which the maximum number of measurements of doubtful fish occurs, in the case of the females, will be seen to lie in close proximity to the determined average size at first maturity. In the measurements of the males, the maximum lies where the size at first maturity would appear to be forecasted. The condition of eight males* occurring in the samples was remarkable from the fact that, although the fish were large, the gonads were in an undeveloped condition, and I am not aware that a similar feature has been recorded before. The majority of the lengths, viz. 40, 41, 47, 48, 51, 51, 53 and 57 em., obviously render the probability of immaturity very remote, and yet to judge by all appearances, these fish had certainly not been in a spawning condition in this year. In * Two more occurred in the earliest samples, but I rejected them, thinking that the apparent absence of reproductive organs was due to accidental removal in gutting. BARENTS SEA IN AUGUST, 1907. 81 one fish, 57 cm., the testis, about 2 mm. wide, was such as is found in the immature condition, but the measurement is the largest in the records for the sex. As regards the other seven fishes, no definite testis could be traced. Whether this phenomenon was due to the lifelong sterility of the individuals, or to the fact that sterility had supervened on account of the great age to which they must have survived, is an interesting biological question which must for the present remain open. Having made an extensive examination of spawning plaice in the southern parts of the North Sea in the spawning season (January— February) this year (1907), I received the distinct impression that the quantity of spermatic fluid and unextruded dead ova was far greater in the Barents Sea fish than in those of the southern region. It would be interesting if investigation should prove this to be actually the case. No females actually spawning or about to spawn were found, and it will be seen from the summary of measurements that the number of immature fish of both sexes was very small, particularly in the case of the males. It is interesting to find that the greatest number of immature occurred in the haul across the shoalest part of the bank (26 fms.) at the end of the first day’s fishing. The catch then consisted of eighteen baskets of plaice, of which four were measured. ‘These con- tained 183 fish (73 males, 110 females). Of the males, 7, or 94 per cent, were definitely immature; and 11, or 15 per cent, recorded as doubtful. Of the females, 24, or 22 per cent, were immature; and 5, or 43 percent, doubtful. Thus, of the fish in this sample, 18 males, or 25 per cent, and 29 females, or 26 per cent were possibly immature. Taking all the other stations, and classing the immature and doubtful fish together in the same way as “possibly immature,” I find only about 3 per cent of the males, and 16 per cent of the females would fall into that category. As a result of the international investigations in progress, we know that the same phenomenon, viz. an excess in the proportions of immature females compared with that of immature males, also obtains on the central grounds of the North Sea at a similar period, The length of the smallest mature male was 24 cm, and of the smallest mature female, 35 cm. The largest immature female was 45 cm. The largest immature male was recorded as 41 cm., but this record is rendered open to doubt by the curious condition of the eight males recorded above. The average size of the mature males is 40:9 em. and of the mature females, 48:3 em. 82 NOTES ON A FISHING VOYAGE TO THE THE AVERAGE SIZE AT First MATURITY. The average size at first maturity, that is to say, the size at which equal numbers of mature and immature fish occur, I find to be about 40 cm. (see diagram, page 79), in the case of the females. In regard to the males, owing to the virtual absence of immature individuals, this size cannot be determined. The indications, however, from the material available, point to this size being not far remote from 31 em. These sizes correspond closely with those Dr. Wallace kindly in- forms me he has determined from 895 females and 561 males for the central grounds of the North Sea (Dogger, Flamborough Off Grounds, Clay Deep, etc.), viz., 40 cm. for females and 31 cm. for males. The correspondence is remarkable, and would hardly seem a mere coincidence. It is evident, however, that the plaice of the Barents Sea mature at a much later age (p. 85). AGE. The age investigation presents many difficulties. It is evident that the rate of growth is extremely slow, and this not only renders the distinction of year groups impossible by a study of the length frequencies (Petersen method), but it is also reflected in the otoliths, on which the annual rings are so narrow and crowded together that only in the case of the smallest fishes found has it been possible to estimate the age with a degree of certainty. I made a small collection of otoliths on board the Roman, and although this material is quite insufficient for obtaining an estimate of the rate of growth, it can be seen that this is exceedingly slow, even during the years before maturity is attained. A noticeable feature of these otoliths is the contrast of the com- parative width of the white and dark rings, the latter being exceedingly narrow. The physical conditions which apparently regulate the deposition of these respective rings have been studied in the case of plaice from the Baltic and North Seas. Various investigators* have found that the white ring first shows itself in spring, when the temperature of the water commences to rise and the fish to feed. In late summer and into the autumn (the period * Rerpiscu. Ueber die Hizahl bei Pleuronectes platessa und die Altersbestimmung dieser Form aus den Otolithen. Wiss. Meeres. Abt., Kiel, N. F. Bd. 4, 1899. Mater. SBeitrdge zur Altersbestimmung der Fische ; Arb. d. wissen, Komm. f.d. Intern. Meeres, No. 5. Bad. viii., 1907. WALLACE. Loc, cit. BARENTS SEA IN AUGUST, 1907. 83 of warmest water and most rapid growth in the North Sea) the dark ring is formed. In winter the growth of the otolith, as of the fish, ceases. Immermann* has shown that these rings on the otoliths of the plaice are purely optical effects, explicable by the regular changes in the life conditions of the fish. Avoiding technicalities, the reason for the occurrence of apparent white and dark rings is as follows: The whole otolith is composed of layers of chalk substance deposited regularly as the growth of the fish is in progress. Restrained growth, as when cold water conditions prevail, has the effect of crowding together these layers. As the temperature rises, and the growth rate of the fish increases, so must that of the otolith, and thus is effected a wider expansion of the layers of chalk substance. The optical effect of this is that the crowded rings, not permitting the passage of light, appear white, whilst the expanded translucent layers appear dark by contrast. The reason for the narrowness of the dark ring, and the comparative great width of the white ring in the otolith of the Barents Sea plaice, is thus afforded. For the greater part of their annual growth-period these fish are subjected to very low temperature (at the time of my visit the bottom temperature was only two degrees Fahrenheit above the freezing point), so that for only a short period would rapid growth appear to take place, and it is not unlikely that this period coincides with the culmination of the Atlantic flood. As has been pointed out before (p. 72), this expansion of Atlantic water is in progress in the month of August; in other words, biological spring has commenced. Correlated with this physical phenomenon the otoliths of the plaice show the commencement of a white ring at the edge. In the North Sea by this time, according to investigations (Wallace, Maier, etc.), the dark ring has commenced. Thus in the two regions of the ocean, many hundreds of miles apart, it can be seen on the otoliths of the plaice that biological spring in the one region coincides with midsummer in the other, as we know to be the case from hydrographic observations referred to above. For suggestions and help in the investigation of the small collec- tion of otoliths, I am greatly indebted to Dr. Wallace, who also kindly undertook an independent investigation of a number. Our two re- sults were in close agreement, the chief discrepancies being in the case of otoliths on which certain of the rings appeared to split in a doubtful manner. * Beitrage zur Altersbestimmung der Fische II. Die innere Struktur der Schollen Otolithen. Arb. d. wissen. Kom. f.d. Intern. Meeres. No. 6. Bd. vi., 1907. 84 NOTES ON A FISHING VOYAGE TO THE In Table III are shown the ages of certain individual fishes, reckon- ing that, as in the North Sea, one white ring is deposited annually, and that each fish had recently completed the number of years specified. In the case of the larger (older) fishes, the outer rings are so crowded together that accurate counting would seem impossible. I have, however, included a few examples of these, estimating the age at not less than a certain number of years, as shown by the number of distinct white rings. If fishes of either sex are not less than ten years old when 40 cm. in length, to what age must a male of 57 cm. or a female 73 cm. in Tasie II].—Showing the age of certain individual plaice from the Barents Sea, August, 1907, estimated according to the number of white rings shown on the otoliths : MALES. FEMALES. NUMBER OF WHITE RINGS. NuMBER OF WHITE RINGS. Length Maturity rc cm. Immature. Mature. Doubtful. Immature. Mature. ZA. . - = — 6 - PAD. : = = 6 - - Dims é 5 9 — 6 - tie = ey 5 oe , ee a 6 us 28 ~ - 10 - = = as 6 = 29 6 9 - 6 - =e = = 6 _ 30 - - 10! 9 - = = = 9 = = = = 10 = BIL sc 8 - - 7 = 7 - - 8 = ss x 8 = zs a = 9 = 32 8 ~ 9 - = = == 9 = = as = 9 = 1B} ig , - 8 - 10 - 34. : - - - not 29 ~ B15) F - - ~ 9 - BH. P - not 211 = = ~ 39. : - not 211 — = Es - not 215 - - - — ila = zs = 40 - not 211 - - - ~ not 210 - - _ 41 - aA = not 212 NOG 22 = not 2138 = ~ ~ a il = = = - not 210 - - - 42. . - not 211 not 211 - = 43. “ - not 215 - _ - 44, . - - - - not Aa ADs ; - not 212 - - - - not 212 - - - 46. ‘ = not 216? - - not 2 20 IYO og ; - - - | - not 221 aoe ; = = = = not 218 1 Probably 10. 2 Probably 17. BARENTS SEA IN AUGUST, 1907. 85 length have survived, considering that each year the growth becomes less and less! Although the material in Table III cannot be regarded as satis- factory, it shows plainly how slow the rate of growth must be, and would seem indicative of the direction future plaice investigations should take in this inhospitable region. In connection with the majority of these specimens (Table IIT), the possibility presents itself that they may be actually amongst the best grown fishes of their respective year groups. That plaice in the North Sea are larger for their age the further they are caught from the coastal grounds has been very clearly shown by Wallace in a recent paper (op. cit), so it seems possible, if not probable, that a similar state of things obtains in the off-shore grounds of the Barents Sea. The youngest plaice of either sex amongst those examined had apparently already completed five years, but this would seem quite exceptional. In addition to the slow rate of growth, the evident late age at which maturity is attained is striking. Amongst these few fish examined for age, no male less than eight years (32 cm.), and no female less than twelve years old (41 cm.) was found to be mature, though younger mature specimens must have occasionally been present in the catch (see Table I). In the North Sea few males are found to survive to eight years. If the plaice in the Barents Sea have really to live through some eight or nine years before they attain the size at which they reproduce their species, the question occurs to us, “How long will the present stock, accumulated through many years, hold out in sufficient abund- ance to make this long, expensive voyage of three to four thousand miles down to the Arctic Ocean profitable to our trawlers ?” MIGRATIONS. Speaking in a general way, the migrations of mature fish seem to be determined by the search for food, or to be in connection with the re- production of the species. Currents, temperature, and such local factors as a general exodus from shoal to deeper water in stormy weather, are amongst other causes of fish movements, but all have more or less direct bearing on one of the main stimuli. Although conclusions as to migrations in the Barents Sea would be impossible from the material collected on the voyage of the Roman, nevertheless every fact in my possession points to a general movement of this mature plaice population from deeper and here probably warmer water, after spawning has taken place, on to the banks to the eastward, apparently in search of food. 86 NOTES ON A FISHING VOYAGE TO THE That rich supplies of molluscs were available, was evident from the frequent occurrence of living specimens in the trawl; the masses of crushed shells in the stomachs of the plaice and catfish; and, perhaps most important of all, the fine, plump condition of the plaice when first caught. This is a striking contrast to the condition met with a few years ago at Iceland, and reported of the earliest trawling times on the Dogger Bank. How sensitive some fishes are to external conditions, when about to spawn, has been pointed out by Schmidt.* The same investigator has found more recently + that plaice marked on the north and east coasts of Iceland, migrate from their cold surroundings towards the warm Atlantic water, when preparing for reproduction. As further contributing to our knowledge on this problem, I find that among the Lowestoft fishermen, whose fishing in January and February is almost entirely confined to the spawning plaice of the southermost North Sea, it is common knowledge that in a severe, cold winter, plaice always set in more abundantly, and remain longer, in the deep channels of this region, than is the case when the winter is mild. Hydrographic observations have shown that the water here is of Channel origin, and has a higher temperature at this period than any other part of the southern North Sea. From the evidence I shall present below, it will be seen that the spawning plaice of the Barents Sea probably seek to the west the more congenial surroundings which their condition demands. The Russian hydrographers{ have pointed out how the ramifications of the North Cape current follow well-defined channels along the sea bottom towards the east, and we may perhaps justifiably surmise that the influence extends to the deep water west of the bank on which the present investigations were carried out. At any rate, it is the experience of our fishermen that the plaice are found further to the west, and in denser shoals, when they first visit these grounds in June and July, than later in the season. I should estimate, from the condition of the fish taken by the Roman in August, that this year the spawning season terminated in July. An analysis of the Loman’s hauls of the first two days, relative to their respective positions and depths, reveals features which bear comparison with North Sea grounds at a similar period, viz., just after * Jons Scumipr. ‘‘ Contributions to the Life History of the Eel,” (Anguilla vulgaris, Turt.), Rapports et Proces-Verbaux, V, p. 234, et seq., 1906. + Marking Experiments on Plaice and Cod in Icelandic Waters. Meddel. fra Komm. f. Havunders., Serie Fiskeri. Bind ii, No. 6, 1907. + Rapports et Procés-Verbaux, Vol. iii, 1905. Appendix A, pp. 3 and 4, BARENTS SEA IN AUGUST, 1907. 87 spawning has taken place. This is in regard to the proportions of the sexes. Recent investigations* have shown that a high percentage of males is characteristic of the catches in areas where plaice are spawning, or have recently spawned. To gain additional knowledge on this point, I made, in the first days of February this year (1907), a voyage in the Lowestoft smack fosebud, and measured all the plaice caught, 2631 fish, of these no fewer than 85 per cent being males. The spawning season had then about half expired. TaBLe [V.—Showing analysis of the total catch of plaice made by the Lowes- toft sailing-trawler “ Rosebud,” January 3lst to February 5th, 1907. Eastern Deep Water :— Cm. <20 20-24 25-29 30-84 35-39 40-44 45-49 50-54 >55 ‘Total. 6 202) “648 =555.. 505, 257 50 OG 2 1 38 148 108 48 33 Dene a 405 Totals 203 686 703 618 305 83 32 4 Py SPAT Percentage of Males 99°5 95 79 82 84 60; 28 0 0 85 Spent Females : ~ 7 18 26 24 18 yea rae 103 Immature Females . 1 26) LS 64 6 = = = «= 212 The early hauls of the Roman, referred to just above, were, roughly speaking, in a series—starting from the deep water to the west of the bank, extending over the same, and dropping again into deep water to the east of it. Three hauls were made up the western slope at depths of 55, 40, and 38 fathoms. The complete catch of two of these hauls, and a greater part of the third, was measured, and the condition of: the re- productive organs examined, the numbers showing that males greatly predominated here. Out of the 294 fish comprising these samples, 179, or 61 per cent, were males; the first haul, indeed, in 55 fathoms, resulted in a catch of 42 fish, of which 33, or 79 per cent, were males. Crossing the bank with water as shallow as 26 fathoms, measure- ments of two hauls were made, these samples amounting to 288 fish. The males now only numbered 123, or 45 per cent. In three hauls down the eastern slope, the water deepening to 49 fathoms and shoaling again to 40, and eventually to 37 fathoms, an eighth, nearly half, and, on the third occasion, the whole of the catch was measured. . A complete reversal in the proportion of the sexes, as compared with the west side, had now taken place. Out of 319 fish dealt with, only 115, or 36 per cent, were males. After the last haul of this batch, the vessel steamed westward on to * Rapports et Procés-Verbaux. Vol. vii, 1907, Comm, B., p. 20. NEW SERIES.—VOL. VIII. NO. 2, G 88 NOTES ON A FISHING VOYAGE TO THE the body of the bank, and fish were eventually found in satisfactory quantities. The remaining 21 hauls, from which fish were measured, give 48 per cent of males. It is evident that this unmistakeable change in the proportions of the sexes from west to east is not without significance, and when we consider that a great preponderance of males is characteristic of spawning areas in the North Sea during, and immediately after the spawning season, it would seem that we have a clue to where these plaice had spawned in the Barents Sea. Evidence of a probable abundance of plaice some little time previously in the deep water to the west of the bank, was accidentally afforded in the following manner: When first approaching the in- tended fishing grounds, a trawler’s fishing buoy was found anchored in 55 fathoms. No vessel was in sight, and it had been in the water some little time, evidently having been lost sight of in one of the frequent fogs. A trial haul of nearly two hours gave the result previously mentioned, viz., 42 plaice, 33 of which were males. Now the experienced skippers who make this long voyage to the Arctic Ocean would only be likely to employ a buoy for one of two purposes—to mark either a rough ground, or a shoal of fish. In the latter case plaice would be the species, for in the present limited scope of the fishery this is the only species specially sought after in this region. No rough ground was encountered in the haul taken, so the prob- ability is that when the buoy was put down quantities of plaice were to be had in the vicinity. It was not until nearly two days later, after searching to the eastward and then returning to the body of the bank, that the Roman fell in with sufficient quantities of plaice to warrant the use of a fishing buoy.* The rapidity with which an accumulation of plaice can under certain conditions disappear from a given spot, is a phenomenon well known amongst fishermen. Thus we have evidence, indirect and admittedly not conclusive, yet from various aspects corroborative of a distinct eastward movement of these plaice subsequent to spawning. Conversely it would appear as if the westward migration, from this bank at least, into deeper water for the purpose of spawning, might be assumed. * Since the above was written, information has been obtained on this point, which corroborates in each respect the surmises mentioned in the text. From distinguishing marks on the buoy, and through the courtesy of Captain Leighton, it has been possible to — discover the Hull skipper who lost it. He states that it was actually on a bank with 52 fathoms, and was lost in a fog of two days’ duration towards the end of June. At that time he was catching sixty baskets of plaice for a two hours’ haul. G. Dear alaOie BARENTS SEA IN AUGUST, 1907. 89 Whither the eggs drift, where the larval forms reach the coastal shallows necessary for the development of young plaice, the life history of these, and where they spend the long years before they reach the outer grounds as mature fish, all afford highly interesting subjects for future investigation. The pioneering trawlers have found that the plaice are smaller near Cape Kanin, as would be expected, but neither here nor in the entrance to the White Sea, has any great quantity of small fish been found. A study of the Admiralty chart reveals the fact that west of Long. 45° E., the water deepens from the coast comparatively rapidly ; indeed, no extensive tracts of shallow water overlying a fine sandy oottom such as characterize the small plaice nurseries in the North Sea, are indicated until Long. 53° E. is passed. Thereafter to the eastward a long, broad area of fine sandy ground extends across the wide mouth of the Pechora River. It is perhaps significant that the glass balls which Norwegian fishermen employ in connection with their fishing gear, have been found at the mouth of this river.* This reminds us of the drift of derelict fish trunks from our fishing fleets in the North Sea, which with other flotsam, find their way on to the beaches of Holland, Germany, and Denmark, as do also the early developing stages of the plaice. That this class of evidence is not without significance is shown by the results of later scientific experiments with drift bottles,+ by which the trend of the surface currents in the North Sea has been deter- mined. How THE INVESTIGATION OF THE PLAICE FISHERY IN THE BARENTS SEA MAY THROW LIGHT UPON THE CONDITION OF THAT FISHERY IN THE NORTH SEA. It is now desirable to see if from this mass of material from a virgin fishing ground, we can gain any light upon the condition of the plaice fishery in any comparable area of the North Sea. It must at the outset be recognized that many conditions of life must differ vastly, and yet we have aspects from which this fishing bank in the Barents Sea and the central grounds of the North Sea are comparable as regards the plaice populations at present found on each. We have the sea bottom in both cases deepening from the coast, whence we may take it the small plaice originate. Far out to sea the * NANSEN. Oceanography of the North Polar Basin, Part II, p. 268. + Futron. “The Currents of the North Sea and their Relation to Fisheries” ; Fifteenth Annual Report Fishery Board for Scotland, Part III, 1897. GARSTANG. “‘ Report on the Surface Drift of the English Channel and Neighbouring Seas during 1897,” Journ, M. B, A., Vol. v. 90 NOTES ON A FISHING VOYAGE TO THE bottom rises, forming a bank or banks, rich in the food of plaice: in one case the Dogger Bank, in the other, this uncharted bank discovered by the fishermen from Hull, and on which my investigations were made. Further seawards in both areas, depths are eventually attained which cease to interest the plaice. In this regard, the Barents Sea is more comparable with the North Sea than is Iceland, where the plaice are restricted by the configuration of the sea bottom to a com- paratively narrow coastal zone, throughout their lives. Biologically, sa a 8 Pe eam a ae ae | a ae a re ead tt Ed tS | {A eae eal LJ id noe = 7 Si RoE Sees He SE waa wb a@mil a5 ae Re Ae ies eae i Al =. A oe y—»%—~% IMMATURE FISH. VERTICAL LINE (M) AVERAGE SIZE ge MATUREVELSH- AT FIRST MATURITY. Fic. 3.—Showing the length frequencies of 895 female plaice from the central grounds of the North Sea (mses Bank, Clay Deep, etc.). The ordinates at 19, 21, 23, etc., represent the frequencies in 2 cm, size groups 18-19, 20-21, 22-23 cm. ete. for both regions, we have this important standpoint from which a com- parison can be obtained. The average size of the females at first maturity was found to be 40 em, (approximately), the same as in the central part of the North Sea.* Moreover, it is remarkable that out of 2365 and 895 fish from the Barents Sea and the central part of the North Sea respectively, the size of the largest fishes definitely determined as immature should be 45 em. (Cf. Wallace, Fig. 3). In order to compare the populations from this standpoint, I have constructed curves of the actual length frequencies of mature and immature female fishes in the two regions (Figs. 2 and 3, pp. 79, 90). For the rich material from which that for the central North Sea is * FuLTON. 20th, 22nd, and 24th Ann. Report. Fishery Board for Scotland. Hour. Journ. M, B. A., Vol. ii. Kye. 18th Ann. Report. Fishery Board for Scotland, WALLACE, op. cit. BARENTS SEA IN AUGUST, 1907. 91 constructed, I am indebted to Dr. Wallace, who has made the deter- mination of the maturity of 895 female fish on the fishing grounds of the Dogger Bank, Clay Deep, and off Flamborough Head. In this curve for the central North Sea we find that the immature females, commencing at 18-19 cm., attain their greatest frequency at 36-37 cm., and ultimately disappear after 45cm. The smallest mature female occurs at 25 cm., with the actual greatest frequency at 40-41 cm. This curve, however, representing the mature fish, Tises again at 46-47 cm., so that it seems that its real mode lies between these groups. The largest fish in this collection was 66 em. long. In the curve for the Barents Sea (Fig. 2), the smallest immature female was at 24 cm., and then, as in the central part of the North Sea, the greatest frequency occurs at 36-37 cm., and the largest immature specimen at 45 cm. The smallest mature female was found to be 35 cm. in length, and the greatest frequency occurs at 46-47 em. (thus coinciding with the second mode in the curve for the mature North Sea females, Fig. 3). The largest specimen had a length of 73 em. The size at which the numbers of immature and mature are equal (the average size at first maturity), represented by the line M, is for each curve in the vicinity of 40 cm. Thus in the Barents Sea with its intact stock of plaice, the mode of the length frequency curve (Fig. 2), viz., 46-47 cm,, is some 7 cm. higher than the average size at first maturity, viz., 39-40 cm. On the other hand, in the diagram (Fig. 3) representing the stock in the central parts of the North Sea, we should naturally not expect to find any such great accumulation of mature fish; but it is somewhat alarming to find that the mode here (36-37 em.) fails by 3 em. to reach the average size at first maturity (39-40 cm.). That is to say, some factor is at work which keeps down the plaice population to such an extent that the greater proportion are not, at the present time, once permitted to re- produce their kind. Jf we compare this with Dr. Petersen’s previous discussion of these points in his paper, “What is over-fishing ?” (Journ. M. B. A., Vol. vi., 1903, pp. 587-94), it would appear as though the chief theoretical effects of over-fishing in the North Sea, suggested in that paper, were now being substantiated.* It may be that this enormous contrast is partly due to the fact that * KyLe (Journ. M. B. A., Vol. vi, p. 496) suggests that one effect of fishing a plaice population is to reduce the average size at first maturity. The Barents Sea will afford the opportunity of testing this; meanwhile, if we were to accept the suggestion that such a reduction has taken place to the extent of, say, 5 cm. in home waters, the deterioration of the stock would be still more evident, and even a greater proportion of North Sea plaice than my curves tend to show would be prevented from attaining maturity. 92 NOTES ON A FISHING VOYAGE TO THE the fish dealt with in the Barents Sea were possibly selected naturally by the function of spawning, and that immature fish had not migrated so far seawards to an appreciable extent. I think this is in part probable, and that in the North Sea a similar state of affairs may have once obtained, but has now undergone the following change :— Formerly the plaice population was dense on suitable areas, from the nursery grounds out to such a central ground as the Dogger Bank, and the food supply was everywhere restricted. The early influence of man’s fishing was to reduce the numbers of the largest fish at pro- portionally the greatest rate, and thus reduce the density of the population on the central grounds. Better feeding conditions would now be afforded on the central grounds, and to these the younger plaice would tend to move more and more, as the reduction in the numbers of the older individuals became more appreciable. At the present time there seems no doubt that density of population is restricted to the nursery grounds, so it is to the advantage of the individuals to radiate rapidly to the more favourable surroundings offshore. Thus it may be that the larger of the im- mature plaice extend further seawards than was formerly the case, Le.; emigrate at an earlier age, in consequence of the reduced competition within the species on the offshore grounds. At any rate, whether it was the case or not in former times, there is now to be found everywhere, and at all times in the North Sea, a proportion of immature fish many times greater than I found this year in the Barents Sea. Even amongst the spawning shoals in the North Sea it is quite usual to find as many immature female fish as mature. On the other hand, it may possibly be that we have on this bank in the Barents Sea an accumulated stock of plaice such as the Norwegian investigators * have shown to have existed in suitable areas on their coast, on a much smaller scale. When these spots were first fished, quantities of large plaice were to be obtained. After a few years, however, the population appeared to have been almost entirely fished out, the explanation being that the currents, setting out of the fiords, carry the majority of the floating eggs and young fish to water in which they cannot develop. The capture of the stock is thus out of all proportion to its renewal by natural means, and the decay of the fishery in these particular spots is inevitable. From this it would seem to be of the greatest importance for the future welfare of the plaice fishery in the Barents Sea, that steps should be taken to ascertain definitely whether extensive nursery * Report on Norwegian Fishery and Marine Investigations, Vol. i., 1900, pp. 138-52. BARENTS SEA IN AUGUST, 1907. 93 grounds actually exist, from which the stock of the outer grounds may be renewed. If the majority of the eggs and larve are carried by currents to regions in which they must naturally perish, as Hjort and Dahl (Joc. cit.) have shown to be the case on parts of the Norwegian coast, it is evident that the fishery can only flourish so long as the present stock, accumulated through a great number of years, continues to be sufficiently abundant to pay for its capture. It is not difficult to imagine that there may have been a period when the central grounds of the North Sea were inhabited by a plaice population, of which at least the majority of the individuals were mature; and, had we a curve of measurements of that period, the mode would conceivably have exceeded the average size at which the fish were first mature, by an amount as great as may now be found in the virgin waters of Northern Europe. One of the earliest effects of fishing on any ground is to reduce the number of the large fish, and consequently lower the average size; that is to say, representing this effect on a diagram to compare with Figs. 2 and 3, the mode will recede to the left, and approach the size at which the species hecomes mature. If it is allowed that an accumulation of mature plaice once pre- ponderated in the central North Sea, it will be obvious that the retro- gression of this modal size to its present position (36-37 cm.) below the average size at first maturity (39-40 cm.) must have been effected gradually by the influence of man, for no serious natural enemy of large plaice in the North Sea is recognised, whilst the intensity of fishing is known to be very great. Hence it is conceivable that if intense fishing continues, the modal size of the plaice will imperceptibly recede to even lower limits, and a period must arrive, if it is not already with us, when the supply of eggs, and consequently young fish, seriously suffers. SUMMARY, In this preliminary investigation of the plaice on a bank in the Barents Sea the following were among the chief features noted :— 1. The population consisted almost entirely of mature fish, thus presenting a marked contrast to the conditions prevailing at the present day in the central parts of the North Sea (Dogger Bank, etc.). 2. The “average size at first maturity” for the females appears to be approximately the same (39-40 cm.) in the Barents Sea as in the central parts of the North Sea: but, whereas in the Barents Sea the 94 NOTES ON A FISHING VOYAGE TO THE predominant size is several centimetres above, in the central parts of the North Sea it is several centimetres below that standard. In other words, whereas on the virgin grounds of the Barents Sea the female plaice live to spawn many times, in the southern much- fished region the majority at the present time do not live to spawn once. 3. The number of rings on the otoliths indicate a remarkably slow rate of growth and great age attained in this region as compared with the North Sea. It also appears from these investigations that “biological spring,” and also the spawning season, is some three to five months later than in the North Sea, viz. in mid summer. 4, On this voyage the differences in the proportions of the sexes at different sizes was striking. Up to a certain size (40-44 cm.) males were in great excess; after this, rapid diminution in their numbers took place. In the North Sea the same two features have been found to occur, and are connected respectively with the spawning habits of the species and with earlier mortality of the male fish and its slower rate of growth. 5, Various evidence points to the existence of a spawning ground somewhat to the westward of the bank where the fishing took place. OTHER SPECIES. The few other species which occurred during this voyage were as follows :— Dab (Pleuronectes limanda). Long Rough Dab (Hippoglossoides platessoides). Halibut (Hippoglossus vulgaris). Cod (Gadus morrhua). Haddock (Gadus aeglefinus). Catfish (Anarrichas (minor ?) ). Greenland Shark (Laemargus microcephalus). Starry Ray (Laia radiata). Lump-fish (Cyclopterus lupus), and Cyclopterus (Humicrotremus) spinosus, Mill. A Cottoid (Gymnacanthus tricuspis). Dab (Pleuronectes limanda). This species was of very rare occurrence in the area visited. Only four were observed, all being large; two of these measured 35 and 36 cm. respectively. On an otolith from the latter ‘fish seventeen white rings appear very clearly, tending to show that the rate of growth of this species, like that of the plaice, is exceeding slow in these waters. BARENTS SEA IN AUGUST, 1907. 95 Long Rough Dab (Hippoglossoides platessoides). This fish occurred in small numbers every haul. It appears to attain a much larger size here than in the North Sea, where the majority recorded by Fulton* are below 15 cm., and only an occasional specimen over 25 cm. A sample of 42 measured from one haul on the Roman ranged from 19-39 cm., the majority being between 25 and 29 cm. Slightly larger and smaller fish probably occurred, but no very small specimens were observed. The species is not brought to market at present. Halibut (Hippoglossus vulgaris). Four only were caught. ° Two measured 66 and 78 cm., the other two being a little larger and a little smaller than the lengths recorded. Examination of the otoliths of the fish 78 cm., a male, shows it to be apparently either seven or eight years old. The species has but rarely been met with in the region, though from the Russian records it would appear to be more abundant further west. The specimens found on this occasion were probably all immature. Cod (Gadus morrhua). Small individuals occurred in practically every haul, and on one or two occasions in abundance. A sample basket (52 fish) out of about three was measured from a haul on the second day, and the whole catch (51 fish) eight days later. The features presented by the tabulation of these measure- ments, if not accidental, are interesting. In the first sample the sizes range 30-49 cm., with an exceptional fish 58 cm., the maximum number of measurements grouping about 40-42 cm. The fish in the second lot had a range of size, 27-52 em., with a very exceptional specimen 82 cm. The maximum of length frequencies occurs some 8 cm. lower, 32-34 cm., with a smaller maximum at 42 cm. ° The possibility presents itself that two year groups are chiefly represented, the younger sparsely at the former station, and _ pre- dominating at the latter, which would be further east than the early haul. The above-mentioned specimen (82 cm.) was much the largest noted, other exceptionally large fish measuring 60, 69, 70, 77 cm., but never * “Rate of Growth of Sea Fishes.” Twentieth Annual Report, 8. F. B. 96 NOTES ON A FISHING VOYAGE TO THE more than one or two such large fish could be found in any haul. Mature cod at this time were thus practically absent from the area visited. Small codling have been found in quantities by the trawlers towards Bear Island. Haddock (Gadus acglefinus). In the first haul (55 fms.) thirty fish were caught ranging from 24-34 cm. Throughout the remainder of the voyage such small specimens were only rarely to be found. Very large fish up to 81 cm. were caught m quantities varying from one or two fish in a haul up to, on one oceasion, 143 fish. These fish had evidently spawned some time previously. An increase in the catch was noticeable in the few hours the sun was below the horizon. In 1906* Dr. Hjort procured some large haddock from the catch of a Hull trawler which had been fishing in this region. His specimens were from 55-80 cm. in length, and their ages determined by investiga- tion of the scales ranged between nine and fourteen years. Catfish (Anarrichas (minor ?) ). I have records of this fish occurring regularly throughout the voyage in number from one to about a score a haul. With one excep- tion (49 cm.) all the specimens were very large. Two catches, 10 and 11 fish respectively, were measured, the range of size being 88-120 and 102-125 em. These ranges and the quantity were typical of most of the hauls in the region at this time. On various occasions stomachs of seven fish were examined. Crustacea (Hyas) and Mollusca appeared to be the staple food, though in one stomach I found three codling. Greenland Shark (Laemargus microcephalus). Called by the fishermen “ oakettle.” Fourteen were recorded, but-one or two more occurred. Of these fourteen, eight were measured, viz., 14 ft. (427 cm.), 12 ft. (866 cm.), 11 ft. 4 ins. (346 cm.), 10 ft. 6 ins. (320 cm.), two specimens 7 ft. (213 cm.), 6ft. 10 ins. (208 em.), and 5 ft. Gin. (168 cm.). No very small specimens were found. Difficulty was experienced in examining the stomach contents of * Jouan Horr. ‘‘Nogle Resultater af den Internationale Havforskning,” Saertryk af Aarsberetning vedk. Norges fiskerier, 1907. BARENTS SEA IN AUGUST, 1907. 97 these cumbersome creatures. Steam power was necessary to remove them from the remainder of the trawl contents, so that this and hoisting over the ship’s side was made one operation. Before cutting the monsters adrift a lateral incision was made through which the liver was extracted. To have opened the stomach as the fish lay upon the heap would not have improved the remainder of the catch. In two instances, however, I was able to examine the stomach contents. In the first instance the food consisted of three codlings, about 40 cm.,and a plaice of the same length. On the second occasion I found in a fish 6 ft. 10 ins. (208 cm.) in length two round fish (one probably a codling, about 60 cm. in length), one long rough dab, and a piece some twelve inches long from the mid-lateral region of one of the salmon species (Salmo salar ?) evidently a large fish. Quantities of plaice could be observed at times pouring from the mouth of these sharks when suspended by the tail and lowered over the ship’s side. That their depredations amongst the plaice are great, I feel convinced. I do not think the missing and damaged tails, so frequent as to be commonly noted by the fishermen, can be otherwise accounted for. I have observed in the North Sea that when the dogfish (Acanthias vulgaris) feeds on small plaice, these are devoured from the tail first, in contrast to round fishes, such as herring, which are taken head first. In my samples, the significant number of 113 fish, or nearly 24 per cent of the total, I found with tails more or less damaged, and subse- quently healed; in some instances the whole tail had disappeared. The possibility of this phenomenon being the result of disease, such as is sometimes found to be destroying the tails and fins of fresh-water fish, would seem excluded, as the damaged extremities were clean and healthy. In the only exception the extremities of the tail rays were raw and bleeding. All these facts, in conjunction with the concave shape of the majority of the assumed bites, seemed to me to point to the successful escape of the individual plaice from the jaws of a Greenland shark, though, as previously suggested, the possibility of depredations by seals must not be overlooked. Starry Ray (aia radiata). This was the only ray species which occurred, and only occasional, full grown specimens were to be seen. Two female fish in one haul measured 35 and 37 em. between the extremities of the pectoral fins. _In the stomach of each of these was found two large specimens of the Arctic shrimp (Selerocrangon boreas), identified by Mr. R. A. Todd. 98 NOTES ON A FISHING VOYAGE TO THE BARENTS SHA. Lump-fish (Cyclopterus lumpus). One medium-sized specimen was found. Lump-fish (Cyclopterus (EHunvicrotremus) spinosus, Mill). Two or three individuals of this lump-fish occurred during the first day or two of the voyage, but it was not observed afterwards. A Cottoid (Gymnacanthus tricuspis, Reinh.) This was represented on the voyage of the Roman by one specimen. For the identification of this and the preceding species, my thanks are due to Mr. L. W. Byrne. EXPLANATION OF PLATE IV. Photograph of a three hours’ catch of plaice in the Barents Sea (about 40 baskets), s.t. Roman, H 948, Aug., 1907. General Chart of Barents Sea. Plate IV. Journ. Mar. Biol. Assoc., Vol. VIII. = Des Photograph of a three hours’ catch of plaice in the Barents Sea (about 40 baskets) s.t. Roman, H 948, Aug., 1907. / Son NORTH CAPE Canute, SS 7o° NORWAY Dmimnim IMM aT rr 2 ee "RE “3 69° Q ae LAPLAND AR » General Chart of Barents Sea. To face p. 98. sins aTARTEU Mateo ag yuo a3iaaaa AMO TIR 2a adel wv aya ya ae ‘ i Ee A r “¢ i * ee Rene oe cot tebe Mar. Biot, Assoc., Vol. VII. senate gee Grabs Sie eT TONE RX aol ENCLISH CHANNEL. WESTERN AREA. CHART TO ILLUSTRATE THE DREDGINGS CARRIED OUT BY ss. OITHONA In 1906. PLATEAU. DES TRIAGOZ jo 4 ea Ay = ATH: —- by pee I PLATEAU DEA--™, eee Adapted by L, R, Crawshay from the Chart of the English Channol published by Imray, Laurie, Norie, and Wilson, 1906, To face p. M0, [ 99 ] On Rock Remains in the Bed of the English Channel. An Account of the Dredgings carried out by ss. “Oithona” in 1906. By L. R. Crawshay, M.A. Assistant Naturalist at the Plymouth Laboratory. With one Chart (Plate V) and two Figures in the Teat. In the programme of work for the summer of 1906, it was decided by the Director that a series of cruises should be carried out by the Association’s steamer Oithona to investigate the fauna of the deeper waters of the English Channel. The bearing 8.W. } S., Magnetic, =S. 23° W., True,* from the Eddystone Lighthouse was chosen as a base- line, and the work was to be carried out with special reference to points at 10-mile intervals along this bearing. The fauna was to be investigated as fully as possible, and bottom-deposits, particularly stones, were at the same time to be carefully recorded and collected. In all, eight cruises were made, the work being extended nearly as far as the 50-mile point. Pending the completion of the report on the fauna collected, it has been decided to issue in a separate form an account of the geological collections that were made, which afford valuable evidence in the light they throw on the history of the Channel. The stones, with which Mr. Worth’s report deals copiously in a subsequent paper, were first found on June 11th at the close of the second cruise at Position (9), bearing S. 31° W. from the Eddystone, 22 miles, and at a depth of about 40 fathoms. The 3’0” dredge was cast to try the nature of the bottom. After an unsatisfactory * Except where otherwise stated, all bearings here given are true, a variation of 16° 45’ W. (say 17° W.) having been allowed throughout, 100 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. haul the arrangement of the gear was modified,* and as the result of a third attempt the dredge came up three parts full of stones. The contents of this haul were of so great interest that it was decided to investigate the subject further, and so far as was possible without unduly interfering with the faunistic work, the most careful attention was given during the subsequent cruises to tracing the extent of these stones and estimating the conditions associated with their occurrence. ; In the third cruise, commencing on June 14th, the course was accordingly set to the position where they had been encountered. The stones were found again without difficulty, and were followed at close intervals during this cruise over a considerable area. Sub- sequently their inner limit was observed at points adjacent to the base-line of the work at some 15 miles outside the Eddystone. Beyond this their extent was still unknown, and much time was therefore occupied at first by short runs about the 20-mile point, which will explain the large number of positions shown on the chart in this region. Finally, from Position (37), 5. 41° W., 17 miles, a test run of 12 miles was made in a south-westerly direction. The casting of the dredge at 6 and 12 miles showed rough ground at both points, one of the dredges being so bent out of shape as to be rendered tem- porarily useless. After this the work was extended on broader lines to the southward. Some general points in connection with the stones will now be considered from evidence afforded in the course of the work. The extent of the area covered by the cruises is shown in the accompany- ing chart (Plate V), where the positions plotted are all of them directly concerned with the stones collected. All bearings and dis- tances are reduced to the Eddystone Lighthouse. The work was done entirely by log and compass, no sextant observations being taken. At the same time much care was taken throughout with a view to securing as close a degree of accuracy as by dead reckoning was possible, and the positions given may be regarded as nearly accurate. (1) Hatent of Exposwre.—The inner limit of the stones, as previously mentioned, was traced by two or three samples at about 10 miles out- side the Eddystone. Here only a very few small stones were found, mingled with the sand and shell deposit which covers the sea- bottom. Inside this point, that is to say, between 8 and 15 miles * That is to say, by attaching a heavy sounding-lead to the hemp warp employed, a few feet in front of the dredge. From this point the hemp warp was dispensed with, and a wire rope substituted for it in all dredgings. ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL 101 outside the Eddystone, the dredges revealed nothing but clean shell- sand. Outside it, however, from the time when the gear was suitably adjusted to the work, there was no single point among the forty-five positions in which either of the larger dredges was used where stones were not found in greater or lesser degree. It may therefore be said that outside this 15-mile point a stony area was traced without interruption for a distance of 34 miles 8.8.W. and for some miles to the eastward and westward of this line, covering a total area of some 300 square miles. At Position (80), the outermost point reached, bearing 8. 16° W., 49 miles, which is slightly beyond the middle of the Channel, both the average size and the average weight of the stones collected were, with one exception, higher than anywhere observed, and there is every reason to suppose that beyond this point similar conditions prevail to within close proximity to the French coast. (2) Intensity—Of the distribution of the stones exposed in point of intensity it is more difficult to speak with assurance, so many are the factors which must enter into consideration: the character and possi- bilities of the gear employed, the variation of local conditions, and the tendency of the dredge to become quickly filled with animal débris in a particular spot, the general success of a haul dependent on tidal and weather conditions; all these tend to complicate the result as shown by the stones actually taken; so that it is difficult to form a just quantitative estimate without a more complete and systematic method of investigation than was possible in the circumstances. From the available data, however, there is little doubt that the stones lie scattered about the surface, with very little interruption over the whole area. In a table appended below (Table I, p. 114) detailed particulars are given of every sample obtained, including the estimated area covered by the dredge used. This estimate as- sumes an average rate of towing of one sea-mile per hour throughout. This cannot be regarded as more than a rough approximation, but it is sufficiently near for the general purpose. Excluding three hauls where no definite result was obtained owing to the dredge being fouled on obviously rough ground, the total area actually covered by the remaining 53 hauls amounts on this estimate to 11,950 square yards. The total number of stones of 4 cm. and over that were collected being 5808, an average ratio of distribution is obtained for the whole area of 0°5 per square yard. Probably this estimate is somewhat short of the true state of things, for it does not take into consideration those stones which are too large to enter the opening of the dredge, nor does it make allowance for 102 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. the limited capacity of the dredge in regard to those positions where the stones are exceptionally numerous. But as a general estimate I do not think it is very far short of the truth, having reference, of course, only to stones exposed at the surface or very little covered. The most reliable test is probably to be found in the result of hauls with the conical dredge and the 1’6” dredge. The former of these instruments is so constituted as to dig deeply with its heavy frame into the sea- bottom, and is therefore allowed to work only for a fraction of a minute, during which time the canvas bag with which it is fitted is rapidly filled with a complete sample of the bottom from a very small area, about 4 to 8 square yards. The 1’ 6” dredge was also fitted with a canvas bag, and though not digging so deeply was used for a very similar purpose. Of five hauls with the conical dredge, from 19 to 49 miles, two produced no stones at all; of six hauls with the 1’ 6" dredge, from 30 to 46 miles, three produced no stones at all; but if these 11 hauls be summarised, and the number of stones of 4 em. and over be distributed over the sum of the estimated areas covered, a ratio of distribution is obtained for these short hauls very nearly equiva- lent to that for the whole area of the work, namely, 0°6 per square yard. With reference to this absence of stones in five hauls with these small dredges, there is no doubt that the stones lie exposed on the sea- bottom very much more thickly in some places than in others, owing to the varying degree of sedimentary deposit in different areas depen- dent on tidal action and the physical conditions influencing animal settlement, and so regulating the local deposition of shell and other débris of animal origin. In the “ Distribution” column of the table it will be seen that the ratio varies as widely as from 0°4 to 28:0 square yards per stone. An interesting case in point occurs in the Positions (10) to (13), 8. 26° W., 18 miles. These four samples were taken in quick succession in a westerly direction over a distance of about 1 mile, and lying thus close together, are shown on the chart as coincident. It seems evident that here the dredgings passed through the middle of a stony patch which was almost covered by finer deposits at either limit. At (10) 6 stones were obtained with an average distribution of 1 stone to 28 sq. yds. ” (11) 166 ” ” ” ” 2 ” BAe) UCN ae diya ss ‘5 " TEN Ps) Od me kas 2 oe CS, To quote another instance, at Position (17), S. 28° W., 23:3 miles, a haul of 11 minutes with the 3’0” dredge produced only 15 stones, ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL, 103 with the small mean dimension of 48 cm., and a distribution of 1 stone to 24°7 square yards. The dredge had here passed through a large and flourishing settlement of Pallasia murata, Allen, and a vast number of the tubes, together with several living specimens of this valuable Polychzte, were brought up in it with little else. As it was evident from the next haul, (18), that we had passed outside the limit of the Pallasia settlement, we steamed back to the ground of Position (17) in the hope of securing some more specimens, setting this run at half a mile. But the Pallasia ground was missed, and a very heavy haul of 34 stones was brought up at (19) with a mean greatest dimension of 10 cm., which was one of the highest averages obtained during the work. These two positions, (17) and (19), cannot have been separated by very many yards from one another, though the results obtained were totally different. Again, the two blank hauls with the conical dredge previously referred to, (71) and (73), at 19 and 29 miles respectively, were followed in each case immediately afterwards by a haul with the 3’ 6” dredge at (72) and (74). The first of these latter gave 213 stones with a mean distribution of 0°8 per square yard. In the second, the safety-stop of the dredge was broken, owing to the rough- ness of the ground passed, and no more definite conclusion was there- fore obtainable than that very heavy stones had been encountered within about a quarter-mile of (73), where the conical dredge revealed only coarse shell-sand. (3) Size and Weight.—A single greatest measurement of each of the stones was taken. Ultimately all stones of less than 4 cm. were left out of consideration, and a mean was obtained for each haul, derived from the products of dimension x number in each case, at intervals of 1 em. Similarly, the samples were weighed, and a mean was worked out in pounds per stone, for each haul. A cursory glance at Table I (p. 114) does not convey any very definite impression as to the relation between size or weight and distance of position from the Eddystone. A certain rate of increase occurs with distance, but it is very irregular. This is evidently due to the fact that the main bearing of the work does not lead directly out towards mid-Channel, but nearly four points to the westward. If a line be drawn due E. and W., Mag., through the Eddystone, a distinct increase is obtained, both in size and weight, in a direction perpen- dicular to this line, 7.e.due S., Mag. Parallel lines being accordingly drawn EK. and W., Mag., at 5-mile intervals outwards, and a mean being taken for all the samples falling within these several intervals, a fairly regular curve is obtained for both size and weight (pp. 10d, 106). NEW SERIES.—VOL, VIII. NO, 2. H 104 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. The disposition of the samples is as follows :— 5-10 miles S., Magnetic 1 sample. ; : 43 stones INCEST Sie ne 18 samples ; se Oa Oe 15-20 ,, : Toreant SODA aa, 20-25 ,, 5 St ples MISA is 25-30 ,, Bs (ieee ; PARE) Wis 30-35 _,, if (Rive hs 5 a WEDD. es 35-40 ,, - 2st : ; 22 eas The area between 20 and 25 miles, represented by three samples, should properly include the sample (74) previously referred to, where the stop of the dredge being broken, owing to the roughness of the ground, no numerical results were obtainable, and the position had therefore to be left out of consideration. There is little doubt therefore that it is owing to an insufficient number of samples that a drop occurs over this area in both curves. In point of size and weight, then, there is a steady increase correlated with distance in a mid-Channel direction. For the loca- tion of the samples, the bearing and distance of all the positions has been reduced to the Eddystone; but the main bearing of the work being 8. 23° W. from this point, that is, almost directly on Ushant, their location must be regarded from a different standpoint, where questions are involved relating to their distance from the English coast. Treating the Eddystone as an outlying point on the coast-line, a line running through it E. and W., Mag. will be roughly parallel to the mid-Channel line, and less than one point off the main direction of Hurd Deep. Outside it the positions fall naturally into the groups from which the curves (Figs. 1 and 2) are obtained at 5-mile intervals, as follows :— 5-10 miles. 37. 10-15, 436, 31, 32, 35,33) 34.410. dy 12/13) 939. 40 Gmalg asian 72, 26, 27. ° 15-20 ,, 14, 20, 21, 22, 29, 30, 34, 25, 17, 19, 18, 42, 41. 2095) 6 7807448 ae 25-30 ,, 55, 56, 53, 44, 50, 51, 58. BO235, ce (BS, 15-6T: 16s Winbs, 62. BAe er 79.80: In connection with the foregoing deductions, two points may here be considered: (1) the size of the stones in relation to that of the opening of the dredge frame ; (2) the position in which they lie. In regard to the first point, the 3’ 6” dredge, the largest used, with a frame of 3’ 6x1’ 0", offered an opening of about 10030 ecm, Sumilarly the 3’0” and triangular dredges allowed of stones at least o¢ cz 0y<4 eed eee Sen or s¢ ‘ouojshppy Woy “| JT “GF S[RAIOqZUT a[TtU-G Loy som04s Jo WoIstatUIp 4sovoIS oSeioAy—"T “OL si Ol salle Tarren 1 ia Ss ECC Case Nee lie ale eae ak | g EB : ij aE S aueeeeesee) es es a plot | a) ala ees aa | Lean aa ‘auoysXppy Woy “| .JT “G S[BAIOJUI a[IUI-g Loy souozs Jo JYSIoM oSvssvAy—'z ‘or q ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. 107 as large as 90 cm. and 50 em. being taken. But it is significant that in forty-five hauls with these three dredges, no stones with any approach to such a size, even in their greatest dimension, were obtained. Among the largest were— four of 20 em. on (19), (77), and (58) five of 21 ,, ,, (19), (58), and (62) four of 22 ,, ,, (19), (53), and (67) onevon, 260 |, 4, 53(08) two of 27 ,, ,, (53) and (80) One OF, 30", 4525, (FT) It may therefore be concluded that, except, of course, in so far as they are largely or wholly covered up, very large stones are not very numerous in this area, and the dimensions and weights shown on the curves may be taken as a fair approximation to the true average. There is no doubt, however, that very large stones and even boulders do occur with considerable frequency, as on the trawling-grounds off Start Point. The heavy working of the dredge communicated through the warp, the breaking of the safety-stop, and the bending or even breaking of the ironwork of the dredge afforded frequent evidence of this. A broken stop occurred at the following points :— (38), S. 384° W., 22:2 miles (39), S. 38° W., 22°2_,, (18), $. 29° W., 23-4, ne S. 25° W., 46-4, At (21), 8. 25° W., 21:2 miles, the 3’0” dredge employed was brought up fast and lost, ie a Coe of one arm being recovered. To break the safety stop, a strain is required of some 600-700 lbs. To sharply open out the wrought-iron frame of the dredges used, in the manner that too often occurred, involves a strain of several hundredweight ; while in the total loss of the dredge at (21), the part- ing of the remaining arm would only be caused by a strain of about twelve tons. At some of these points, then, and at (21) in particular, heavy boulders must have been encountered, the size of which can only be estimated at a rough minimum. As regards the second point, the position of the stones as they lay when dredged up, there is ample evidence to show that, with very few exceptions, they were well exposed at the surface of the sea-bottom, and that they have probably so lain for a considerable time past. Almost without exception, they supported living animal growth or its remains—Porifera, Hydrozoa, Polycheta, Polyzea, Mollusca, ete. Searcely any of the stones were without investing Polyzoa, which often covered the greater part, sometimes the whole, of the surface. 108 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. A large majority supported living Hydrozoa, in addition. The animal growth often showed well-marked limits above an underlying bare portion on which the stone had rested in its bed, evidently undisturbed for a long period of time. Such a position, with the greater part of the stone exposed, was the commonest; but in places, especially near mid-Channel, on (80), 8. 164° W., 48:9 miles, evidence pointed to the stones resting more openly on one another, with very little fine deposit associated with them. Under the more ordinary conditions, with the exposed stones lying scattered about at intervals of a yard or two, in an even shelly or sandy bed, it is not surprising that the bottom of the Channel has been so widely charted as sand and shell, the lead rarely happening to strike these stones except in places where they are exposed to an abnormal degree. There is much reason to believe that the intervening deposit of shell and sand forms for the most part only a thin covering, and that if this could be penetrated to a depth of not many inches, the true bottom of the Channel over the whole of this area would be revealed as an uninterrupted stony bed. (4) General Form.—The stones exhibited every gradation of form, between that of perfectly rounded outline and sharp angulation; the fact that numerous examples of these two extremes repeatedly occurred in the same sample is sufficient to show that little or no wearing action has taken place in recent times. Frequent instances occur of a sequence of events: (1) complete rounding; (2) sharp fracture ; (3) secondary rounding; but the ultimate investment of animal growth . afforded constant evidence in such cases of the secondary rounding not being recent. (5) Bottom-Deposits—Thirteen hauls were taken with the conical and 1’6” dredges, two of them being from positions at eight to nine miles outside the Eddystone, and therefore well inside the point where the stones first appear. I am indebted to Mr. R. A. Todd for his assistance in grading the whole of these samples. The results are given in Table II (p. 117), where the samples are arranged in order of their distance on a S.W., Mag. bearing from the Eddystone. The method of grading is that adopted at the Lowestoft Laboratory for estimating the texture of bottom-deposits in connection with the International Fishery Investigations. The material is separated into eight grades by washing it successively through a series of sieves with circular perforations of 15 mm., 10 mm., 5 mm., 2°55 mm., 1°5 mm., 1:0 mm., and 0°5 mm., the residue which passes through the 0°5 mm. sieve forming the eighth grade. The exceptionally high proportion of “shell” contained in these samples, that is to say, fragments of the shells of Mollusca, fragments of plates and spines of Echinodermata, ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. 109 and fragments of Polyzoa, especially Cellaria and Cellepora, rendered the accurate grading of them a difficult matter, owing to the repeated breaking of the more delicate fragments in the sifting process, so that some small excess error must be allowed for throughout in the direction of the finer grades. The percentage of Carbonate of Lime present in the material above and below the dimension of 0°5 mm. has been determined as shown in Table II. ‘The proportion of this due to inorganic matter is so slight that the percentage may be treated as representing entirely organic remains. For convenient comparison of the samples an “average grade” is added in each case. This method of averaging the samples, which was used by Mr. Worth in estimating the texture of bottom-deposits of the Start to Eddystone Grounds,* consists in multiplying each grade-percentage by its conventional number (15mm.+ =I,. ..20°5mm.= VIII) and then dividing the sum of the products by 100, the quotient being the average grade of the sainple. It is an interesting point to observe that in these samples, as is shown in Tabie II, there is a distinct tendency for the average grade to decrease, 7.e. for the texture to become coarser, with the increase of distance outwards, as far as (75) at 38 miles, beyond which an increase occurs up to (79) at 48 miles. If these few samples be grouped together on broad lines of 10-mile intervals on a S8.W., Mag. bearing, the combined averages appear as follows :— 5-10 miles. >it 00%, . Average Grade, 7°576 HCO eink Jb dt. eeoutld % 9 6-524 QO ADE oi Shy into hoe 285.50) x 6-480 RIPON iis BO, 70,76 ae 5-255 ROSH Eee. 5 6On6E, 19 bus, if 5-033 Sample (50 ), falling on the 30-mile point, is included in both intervals between 20 and 40 miles. While this method of averaging is useful as indicating the com- parative texture of the samples, it is open to the objection that the inclusion of the coarser grades may unduly influence the result in the way of obscuring the finer ones. If the coarser grades be disregarded, and only those below and including 1 mm.+ be considered, the average percentage of material within this range for the samples grouped in the same manner as before works out as follows :— 5-10 miles ; : : . 95:0 per cent. 10-20 ,, ‘ : : Bry ene tis; 35 ; 20-30 _,, ; ' : BA (OS 2h mc 30-40 _,, : t : ye ee 40-50 ,, : : : el Oa. * Journal of the Marine Biological Association, Vol. V, p. 381. 110 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. In most of the samples the smaller particles, both organie and inorganic, show a good deal of rounding and often a high polish, and in all of them there is almost or entirely an absence of silt.* Few as these samples are and irregularly disposed over so great a distance, the fragmentary evidence afforded by them is important in its bearing on the final question to be dealt with. (6) Conclusion—One point remains to be considered in conclusion. How is the exposure of these stones at the present time to be accounted for? The Channel bottom is probably disturbed to a con- siderable depth by wave action in stormy weather, though to what degree is a matter yet to be investigated. Fine particles of sand and other matter have often been taken in the tow-net at a considerable distance from the bottom, and even at the surface, in water as deep as in any part of the Channel. It would be difficult not to attribute this, in some degree, to wave action. It is commonly asserted by fishermen that on the trawling-grounds off the Start, in 35 to 40 fathoms, they are much more liable to have their trawls fouled by large stones immediately after stormy weather than at other times, the belief prevailing that at such times the boulders become more exposed owing to the disturbance of the fine deposit. A case in point occurred quite recently (December 15th, 1907), after an exceptionally rough spell of weather, when some of them encountered heavy stones on these grounds, and by one of them, the Brixham trawler Love and Unity, a block of granite was brought into Plymouth weighing 833 lbs.t Probably there is much truth in this impression, and the influence of wave action should be considered as partly contributing to the con- tinued exposure of the stones far out in the Channel. But the direct agent must be sought for in the tides, and I think it will be found that the tidal conditions in this region are sufficient to explain the cause at work. As far at least as about the 40-mile point referred to in these cruises, there appears to be a constant gain on every complete tide in a north-easterly direction. The meridian of the Eddystone is roughly the western limit of the conflicting tidal conditions caused by the Dover Stream, involving at intervals an opposite direction of the current in the easterly and westerly portions of the Channel. When in this westerly part of the Channel the tide turns to flow, it has to encounter, to the southward of the Eddystone, a still strongly ebbing stream from Dover. Aided by the northerly set from the Bay of Biscay, it is forced against this in such a way as to be deflected to the * ¢.e. matter which remains in suspension in water at the end of one minute. + This stone is referred to by Mr. Worth on p. 122. ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. 111 northward and north-eastward, and it is only when the Dover ebb has slackened, some time afterwards, that the direct up-Channel flood can be resumed. On the turn to the ebb the case is different. The two streams simply flow away from one another, and there is very little or no appreciable deflection through the south. While there cannot perhaps be much doubt as to the existence of this north-easterly gain, nearly as far, at least, as mid-Channel, the existing data available are too incomplete to admit of its being definitely estimated with confi- dence as to the result. I have made reference to the surface current measurements as shown in the Lnglish and Irish Channel Tidal Streams, compiled for the Admiralty by Commander Simpson, R.N., and in order to form some estimate on this basis the measurements of the mean current between neaps and springs for each hour were combined, and a mean resultant worked out for one complete tide at 10-mile intervals 8. 23° W. from the Eddystone. The values thus obtained are as follows :— Eddystone N. 23° E., 10 miles. . N. 24° E., 2:2 miles s z DOI es is sta Nee 2 aE eS i 7 = 31) ees sh Ni BO aE Lhe s! : ee See Oar cel 2s are These results must, of course, be treated with reserve. In the first place, they are derived from measurements in which, admittedly, too great reliance must not be placed on detail; and in the second place, they are surface measurements, and, however accurate as such, do not necessarily represent the condition of things at the bottom. But they show a remarkable degree of regularity in the general result, which seems to justify their being given here. The most doubtful point is that at 50 miles, where different conditions arise with the commencing approach to the French coast, and there is more southerly drift than at the other points. Owing to the difficulty of estimating closely from the tidal charts the force and direction of the current here at some intervals of the tide, the position has been left out of considera- tion. Close to this point, Mr. D. J. Matthews has made, from time to time, a number of measurements with the Ekman-Nansen current meter. In August, 1905,* he was able to carry these observations through one complete tide at different depths. From his 22 measure- ments at the surface on this occasion I have derived a resultant of S. 4 W.,0:96 mile. At 70 metres, however, his 18 measurements give a resultant of 8. 21° E., 0-40 mile. The gain at this point would there- fore seem to be a southerly to easterly one. The most important * Conseil Perm. Internat. pour lV Expl. de la Mer, Bulletin Trimestr. August, 1905, Part B., p. 25. 112 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. point in Mr. Matthews’s observations in the present connection is the fact that he has found a stronger current at 70 metres than at the surface. On this occasion, which was about the time of three-quarter Springs, it amounted to as much as 13 miles per hour. In the pre- ceding May,* he made, on the same station, a series of measurements at 90 metres ze. close to the bottom, extending through almost one complete tide, but not, unfortunately, in quite sufficient detail to admit of a resultant being taken. The force of current then measured rose to as much as 0°5 mile per hour, and as it was only one day subsequent to the date of the Moon’s first quarter, one may fairly safely assume at high Springs a bottom velocity, at this point, reaching 1:5 knots or more. It is on this latter point that the main question turns concerning the exposure of the stones. If it should be true, as evidence seems to point, that there exists a constant tidal gain on the English side of mid-Channel in a north-easterly direction, and in the more central waters, as would seem from Mr. Matthews’s observations towards the south-east and south, this fact, combined with the presence of a bottom current reaching as much as 1} knots, would be sufficient to explain the exposure of stones. No fine deposit could accumulate with this gradual shifting process constantly at work in the outer waters of the Channel. It must be passed on elsewhere, perhaps to come to rest ultimately off the English coast-line, or, on the other hand, it may be, to be carried through the south towards the Atlantic. The evidence afforded by the bottom-samples that were taken with the conical and 1’ 6” dredges tends to support this conclusion. Outside about ten miles from the Eddystone no instance was found of what could, strictly speaking, be called a fine deposit. Beyond this point the deposits obtained might be described in general terms as coarse shell-sand mingled with fine or coarse gravel and usually stones, with a very small proportion of quartz grains. Except in sample (50), S. 16° W., 30°9 miles, the material above 1 mm. in grade comprehended within the range of Table II, amounted in all cases to more than 30 per cent of the sample. In most of them it exceeded 50 per cent. Sample (50), moreover, cannot by any means be regarded as of a fine grade, since it also contained in addition to the finer deposit indicated in Table II, several stones with an average greatest dimension of 6 cm.t Further, it has already been pointed out (p. 109) that this coarser texture of * Id. May, 1905. Part B., p. 94. + The same point applies to several of these bottom-samples, in which the inclusion of stones would have been too cumbersome for the purposes of Table II; cp. especially sample 79 (Table I, p. 116), where the larger stones averaged 0-67 lb. per stone. ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. 113 the bottom deposit increases with distance outwards, or conversely, the percentage of the finer deposit increases as the coast-line is approached, till at some eight to ten miles outside the Eddystone there is found, in 40 fathoms, a deep accumulation of fine sand, 92 to 95 per cent of which is less than 1 mm. in grade.* It would be difficult to account for these facts except on the assumption that there is a constant tendency for the finer material to be drifted, by combined tidal and wave action, from the outer waters of the Channel towards the coast-line, the direction of the drift being apparently, so far as the English side of the Channel is concerned, north-easterly. On such an assumption, with the continuous trans- portation of the finer material from the more distant positions, the greater degree of exposure of the stonesin like proportion would be accounted for. Without the presence of a constant process of the kind no explanation would seem adequate to account for the fact that in the midst of shifting deposits brought from other regions and continuously augmented by the local growth and decay of numerous lime-secreting organisms, even small pebbles of no more than a centi- metre or two in height are found again and again, affording an un- disturbed base for delicate animal growth, evidently for a long period. Whether the present conditions are undergoing any change, or whether they represent a state of equilibrium maintained between the factors of deposition and tidal action it would be of deep interest to know. In either case there is very little doubt that at the present time, over almost the whole of this area, the true stony bed of the Channel is but barely obscured by a very thin, superficial covering. * It must, however, be expressly stated that it is not intended here to assign to this last formation, represented by the samples (2) and (69), an origin in the outer waters of the Channel. The inference is rather that somewhere between it and the region of sample (71) the outer Channel drift encounters an opposing action of coastal currents, to which latter it would seem that this distinct deposit is properly to be ascribed, thus preventing its further distribution seawards and deflecting.the outer Channel drift itself from the actual coast-line.—L. R. C. [[aavss pue [[oys UexoIg] | ST-0 | F-0 9.¢ 9cz | 0-88 801 G aspoip repnsueLy, bP PIG. 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AGNV AOddyud TVOINOO HLIIM NAUMVLI SHIdNWVS AM NMOHS SV ‘SLISOdHC WOLLOG HO AYOLXAL JUL CBeanyg, eerie.) The Dredgings of the Marine Biological Association (1895-1906), as a Contribution to the Knowledge of the Geology of the English Channel. By R. Hansford Worth, F.G.S. With Plates VI-XVII (including five charts) and four figures in the Text. INTRODUCTION. INVESTIGATION of the geologic problems connected with the English Channel is no new matter. Setting aside all speculations deriving from the study of its coast-line, the first serious examination of the bed of the Channel was made by R. A. C. AUSTEN, and his results published in the Proceedings of the Geological Society, 13 June, 1849. Although, as he states, he had examined the sea-bed with dredge and sounding-lead he has little to say as to its lithology. But none the less his work is a notable contribution to our knowledge, and his conclusions bear well the test of subsequent discoveries. Following AUSTEN, in 1871, DELESSE published his Lithologie des Mers de France, in which considerable attention is given to the Channel; and the lithology of its coastal deposits, and to some extent of the sea-bed, is considered in detail. But, valuable as this work is, its chief interest lies in the information given as to the nature of the sea-bottom, the grade and extent of the varying deposits. AusTEN and DELEsSE alike, and in agreement, point out the large areas of the Channel bed which are occupied by stones, boulders, and pebbles of some size, and argue on much the same lines as to the conditions which have formerly existed there. In 1879 the petrology of the English Channel was first seriously attacked. Mr. A. R. Hunt then published in the 7ransactions of the Devonshire Association a paper “On a Block of Granite from the Salcombe Fishing Grounds.” This was followed in 1880, 1881, 1883, 1885, and 1889 by five papers entitled, “Notes on the Submarine Geology of the English Channel off the South Coast of Devon.” And, in 1896, the same author added later information in his paper on THE GEOLOGY OF THE ENGLISH CHANNEL. 119 “West Country Geological Problems,” published in the same Transac- tions. It is noteworthy that Mr. Hunt was on the track of a shore problem when his attention was thereby directed to the large boulders occasionally trawled by the fishermen off the south coast of Devon, and it is to these boulders that he confines his work. None the less he stands the first to really approach the matter from the point of modern petrology. Meanwhile, in 1886, the late R. N. Wortn had taken up the question on very similar lines, and in the Quarterly Journal of the Geological Society, in August of that year, he reported the existence of a submarine Triassic outlier off the Lizard; in a subsequent paper, in the Transactions of the Royal Cornwall Geological Society, he dealt with a similar discovery off the Dodman. Here the matter rested until, in 1895, Dr. ALLEN commenced an investigation into the fauna and bottom-deposits near the thirty- fathom line from the Eddystone grounds to Start Point. In the course of this work numerous samples of the bottom-deposits were taken, and in vol. v, no. 4, of this journal will be found, incorporated in Dr. Allen’s paper, some notes on these. The geologic results were subsequently dealt with at greater length by the present writer in the Transactions of the Devonshire Association, 1899, xxxi. pp. 356-75 (“The Bottom-Deposits of the English Channel from the Eddystone to Start Point, near the Thirty-Fathom Line”). Since 1899 the inshore grounds nearer Plymouth have also been subjected to an ex- amination on similar lines, and additional geological information obtained which has not hitherto been published. In the present paper it is intended to incorporate the whole of the previous results with the work done in 1906, of which latter an account is given by Mr. Crawshay in the preceding pages. By Mr. A. R. Hunt’s kind consent an abstract of his petrographic work is added by way of an appendix, which, with other short appendices, will bring together the whole of our present knowledge of the geology and petrology of the western part of the English Channel. Mr. Crawshay’s long line of dredgings, extending to a point near 50 miles S. 164° W. from the Eddystone, and Mr. Hunt’s specimens, which reach 43 miles E. of the Eddystone, between them cover a large area; while to the westward for a distance of 36 miles we have the records of the late R.N. Worth. The difficulties which exist where no field work is possible are naturally considerable, but, as the writer has endeavoured to show elsewhere, very definite results, within certain limits, may be obtained by an inquiry of this kind. Other usual observations being barred, lithology becomes of the utmost importance, NEW SERIES.—VOL, VIII. NO. 2. I 120 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: and the microscope invaluable, since much of the minuter evidence afforded by a rock is as direct and positive as that on a large scale. It has been impossible to microscopically examine every variety found, but one hundred sections in all have been prepared, and it is hoped that most of the rocks may safely be grouped around those thus represented. Before entering upon detail, it may be well to pass in review the manner in which the problem has been attacked by the various investigators. AUSTEN used both sounding-lead and dredge, he differ- entiated the textures of the deposits, giving such statements as that the gravel was of the size of almonds, beans, olives, walnuts, or the ground was stony, or large angular and rounded blocks occurred; he mentions flint, granite, black granite, tin-stone, serpentine, etc., but with no clearer lithological definition, and he records any shells of littoral species found in the deeps. His observations covered the whole Channel bed, but not closely, and extended from the Nymph Bank to near Dover. DELESSE, with greater attempt at detailed location, but with less information as to the size of the constituents of gravels, maps out the Channel, discriminating between areas covered by ‘argile, ‘craie,’ ‘sable, ‘sable riche en coquilles, ‘sable sur les roches pierreuses,’ ‘roches pierreuses, ‘roches en pierres désagregées,’ and ‘roches en pierres pourries ou décomposées.’ He trusted to the sounding-lead for his samples, and none is recorded as coarser than gravel, while none which came from a greater depth than 28 metres is lithologically examined in detail; most were obtained very near the French coast. Hunt chiefly derived his material from the occasional boulders captured in fishermen’s trawls off the south coast of Devon; the more part of these were decidedly heavy, ranging from about 3 to about 12 cwt. All were examined microscopically by modern methods. R. N. WortH was supplied with blocks and stones of some size which had become entangled in long lines or bolters; he, too, examined the rocks microscopically. THE ASSOCIATION has conducted systematic dredgings and endeavoured to obtain fair samples of the bottom-deposits, including sands, gravels, pebbles, and small boulders. Its gear has not permitted the capture of the larger blocks which undoubtedly occur, but three of these have been traced which have been obtained by fishermen, and hand speci- mens taken. Where pebbles have been dredged, in the later work at least, these have been entirely depended on for information as to the lithology of the station; in the earlier work, where pebbles were scarce, the sand was examined in detail also. The superior facilities THE GEOLOGY OF THE ENGLISH CHANNEL. 121 which the Association enjoys advantages it greatly, but our debt to the earlier workers remains undiminished, and in many instances they have preserved evidence of great importance, which must otherwise have been. lost. PETROLOGY. To avoid the confusion which might arise from the system of numbering the dredgings, whereby three distinct sets of samples have all been numbered from 1 onward, the following method has been adopted. Actual hand specimens from Dr. Allen’s first dredgings are referred to by the reference which the slides bear in the writer’s collection, similarly specimens from the second set of dredgings further inshore, this will always be found to be a double number, such as “356/1”, with sometimes a letter added also. In those cases where sands only have been examined, all of which occur in Dr. Allen’s dredgings alone, the station number already published in the Journal is used, prefixed by the letter “A.” The most recent stations, of last year’s work, have the letter “M” set before the number; and Mr. Hunt’s own figures are used with the letter “H” prefixed. Mr. R. N. Worth’s specimens bear a number prefixed to which is the letter “W.” Where more than one rock is described from a station small letters -are added after the number, by which the various specimens are discriminated. With reference to the dredgings taken last year, the rule has been adopted that if several varieties or specimens of one class rock have. to be described, those are set first which are nearest the Eddystone, and of those at equal distance precedence is given to the more western. Throughout, the abbreviation “ Edd.” represents the word Eddystone. GRANITES AND ALLIED ROCKS. A large number of specimens, generally distributed over the area examined, fall within the popular acceptation of the term ‘ Granite, but the greater part of these when submitted to microscopic examina- tion must be transferred to the Quartz-diorites in consequence of the distinct preponderance of plagioclase felspars. Since it is impossible to be certain in which class to place many of the specimens on mere inspection, and it has been out of the question to section all, those as to which any doubt exists are hereafter collected under the head of ‘Granitoid Rocks,’ GRANITES. Boulder. 8.S.W. Start, 15 miles. Weight about 8 cwt. A fine-grained white granite, with very uniformly disseminated black mica. The little felspars are bright and fresh, and the simple 122, DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : twinning of orthoclase shows in almost every one. Some of the felspars are slightly tinted yellow by powdery decomposition products, The mica inclines to a reddish bronze lustre. The general structure of the rock is very uniform. In the section a portion of the felspars is seen to be slightly clouded. The more part are orthoclase, but the orthoclase at places encloses small crystals of triclinic felspars, of which larger areas also occur. There is a tendency to zonal structure in some of the felspars, and there are a few very small areas of graphic structure. The quartz con- tains fairly numerous fluid inclusions with bubbles, some apparently empty or gas-filled cavities, and frequent hair-like microlites, probably apatite. Almost all the mica is brown and intensely pleochroic, but associated with this is a little which is colourless and shows no pleochroism. Apatite is present. Boulder. 8.W. by S. 38. Bolt Head, 19 miles. Weight 833 lbs. A coarse rock of granitic texture. The felspar gives bright cleavage surfaces, but is largely yellow-stained by dusty decomposition pro- ducts; there are no good crystal outlines. Black mica occurs in patches of granular texture. The large orthoclase areas are seen in section to be intergrown with plagioclase, narrow irregular and only approximately parallel strips of which penetrate the orthoclase; all the strips in each crystal ex- tinguish together and in a different position to the main crystal, and all show lamellar twinning, the direction of which is constant through- out the crystal; thus the intergrowth gives rise to micro-perthite. Those felspars, the less numerous, which are clouded with decomposi- tion products, all appear to be triclinic. The quartz presents numerous fluid inclusions, and in places is crowded with other in- clusions which appear as a fine black dust; there are also small acicular microlites. The mica passes from olive-brown to dark green on rotation, but there is a little that is almost colourless. M. 58b. 5S. 22° W. Edd., 39 miles. Medium textured granitic rock, pale flesh-coloured felspar, dark and light mica. Structure granitic. Felspars clouded brown. There are small patches of very well defined graphic structure, here the felspar is clearer. Multiple twinning can still be detected in places. Nearly half the felspar is still almost clear; none of this shows plagio- clase twins. Much colourless widely biaxial mica. Quartz plentiful, crowded and lined by fluid inclusions, all with bubbles ; many of these inclusions are of comparatively large size. There is a little apatite, and in one part of the slide a chloritic mineral fills the cracks in a felspar. Journ. Mar. Biol. Assoc., Vol. VIII. Plate VI. M. lla, 8. 26° W. Edd., 17:8 miles. Micro-pegmatite. Crossed nicols, x 29. M. lla. 8. 26° W. Edd., 17:8 miles. Micro-pegmatite. Crossed iicols. x 974. To face p, 123. THE GEOLOGY OF THE ENGLISH CHANNEL. WAS MICRO-PEGMATITE. M. lia. S. 26° W. Edd., 17°8 miles. ted granitoid rock of fine grain, black mica. Many felspars clouded entirely with red-brown decomposition pro- ducts. Others, but fewer, almost clear. Some crystals are practically opaque in the centre, clear outside, with successive narrow zones of brown. Graphic structure is well developed; often where it has invaded a felspar crystal there will be included in it small perfect crystals free from this structure. Repeated twinning is rather rare. The fluid inclusions in the quartz are very small, most have bubbles, and extremely rarely a cubic crystal occurs. There is a little dark green biotite and some ilmenite. The graphic structure is the great feature of the slide. (Plate VI, figs. 1 and 2.) APLITE. M. 1le. 8. 26° W. Edd., 17°8 miles. A fine grained red granular rock with nests of schorl visible in the hand specimen. An aplite consisting of quartz and felspar only, except for the tour- maline above mentioned. Structure microgranitic. Felspar red, and somewhat clouded in parts, mainly orthoclase, but plagioclase present. The quartz contains numerous and rather large fluid inclusions, nearly all with bubbles, many with crystal inclusions. Most of the tourmaline is indigo in colour, but some small crystals give brown to blue pleochroism. This might be a type rock from Dartmoor. It can be matched in situ in the valley of the Tavy toward and below the lower end of Tavy Cleave, and a precisely similar rock was found as a small boulder resting on the rock bed some hundred feet below the surface of the mud at Keyham Extension Works. M. 27x. §S. 19° W. Edd., 18°3 miles. A schorlaceous aplite very similar to M. 11e., but which has not been microscopically examined. M. 24g. S. 24° W. Edd., 22°5 miles. Granular felsite of rich red colour. The section exhibits microgranitic structure. All the felspars are more or less clouded, a few considerably, and in some cases the ordinary optical properties are destroyed. Orthoclase distinctly predominates, but plagioclase twinning is not rare. The felspars show rounded out- lines, marked in some instances by a narrow line of iron oxide, and flakes of hematite occur in some of the crystals. The quartz shows 124 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: fairly numerous fluid inclusions of very small size. No other mineral is present. The rock must be classed as an aplite. Similar rocks to 24g are 34e, S. 28° W. Edd., 18°5 miles and 14e, §. 24° W. Edd., 20 miles. FELSITES. Under this heading are placed a number of rocks which fall readily into three groups, the first of which consists of two specimens, almost identical in character, and very familiar in appearance to any one who has an acquaintance with the Permian and Triassic rocks of Devon. M. 27c. S. 19° W. Edd., 18°3 miles. Compact red-purple felsite, with light porphyritic felspars and black mica. Fracture trachytic. Has all the appearance of one of the new red felsites. M. 41a. S. 364° W. Edd., 26°6 miles. Felsite, texture trachytic, colour red-brown, small dull white por- phyritic felspars, and a little black mica. Cryptocrystalline ground- mass. A few idiomorphic felspars. A few porphyritic quartz crystals with corroded outlines. Well developed, highly pleochroic brown mica. The ground-mass contains numerous microlites, also many small fel- spars outlined in or largely replaced by hematite. Flakes of hematite are very numerous. A typical red-rock felsite. The specimens placed in the second group form a series, commencing at the Hand Deeps and terminating M. 62, 46:4 miles 8. 25° W. from the Eddystone. Of these the northernmost example has been subject to considerable mineral alteration; the southernmost is the most fresh, and in the latter the porphyritic constituents are more prominent than in any other. The northernmost is probably alone in that it contains mica. All are strongly reminiscent of rocks elsewhere associated with the Permian and Trias. 354/3d. Slopes of Hand Deeps. A erey rock, with a slight shade of green and small purple spots. Small felspars appear, colour buff, all somewhat decomposed. At places the tint of this rock varies to yellow and to purple. There are minute black specks of a hard mineral, and calcite is developed on joint faces. ; Microscopically the ground-mass is seen to be crypto-crystalline with much minute calcite, areas of which mineral also occur. Small felspars are scattered through this mass, and are about uniformly divided between orthoclase and plagioclase. Quartz occurs in small patches of interlocked granules. Mica is now almost entirely replaced by pseudomorphs in limonite and magnetite. THE GEOLOGY OF THE ENGLISH CHANNEL. 125 M. 36e. S. 37° W. Hdd., 17°5 miles. Sub-conchoidal fracture. A dull purple rock, with parts more drab in colour, flesh-tinted felspars in a horny matrix. M. 35d. 8S. 32° W. Edd., 18 miles. Grey, with warm tinge, purple mottling, sub-conchoidal fracture, minute flesh-tinted felspars, mostly much decomposed. M. 20a. S. 25° W. Edd., 20°5 miles. Compact rock, very like 354/3d. in general appearance, but without the small black grains and the calcite. Rather harder than that rock. Grey in colour with warm tinge. Small flesh-coloured felspars, many of which are decomposed. M. 21b. S. 25° W. Edd., 21°2 miles. Compact light grey-drab felsite, red mottling, porphyritic quartz. Crypto-crystalline felsitic ground-mass, in which porphyritic quartz is freely developed; the crystals, although rounded at the angles and at places invaded by the felsitic matter, are largely bounded by straight lines. Minute fluid inclusions are not uncommon, but comparatively the quartz is clear. The felspars are almost formless and ill differen- tiated from the ground-mass; micro-perthite is indicated in some individuals. There is a small yellow patch of some granular mineral showing brilliant colours between crossed nicols. This same mineral is also sometimes associated with the dusty, somewhat dendritic red oxide of iron which gives the rock its mottling. M. 62c. S. 25° W. Edd., 46°4 miles. A green-grey compact rock, with much quartz and fels»ar irregularly distributed. The felspar is pink. The porphyritic constituents more prominent than in any of the preceding. Calcite is freely developed on joint faces. The third group would appear to bear a close relation to the granites which form a prominent feature of the lithology of parts of this area. In this respect they probably stand much as the very hard India-red felsite so freely found on the Hallsands Beach does to the granites of Dartmoor. All are horny in texture and have a sub- conchoidal fracture. M. 12f. §&. 26° W. Edd., 17°8 miles. No detailed notes taken of this rock. M. 72d. S. 23° W. Edd., 19 miles. India-red, compact felsite, occasional small red felspars. M. 9a. S. 31° W. Edd., 21°7 miles. Red felsite. Green porphyritic felspars, compact texture. Ground-mass crypto-crystalline. Felspars much decomposed, the green 126 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : shade being due to a secondary mineral. This traverses the crystals along irregular cracks, and sometimes extends from them a short way into the ground-mass, continuing the line of the crack; it is also generally distributed in the crystal. The less altered felspar is pale red in colour. The green mineral is often fibrous and -sometimes granular, it has a high double refraction; apparently we are dealing with epidote. Quartz crystals, somewhat corroded, are rather common, and show a fair number of very minute fluid inclusions with bubbles. Titanic iron ore is scattered in small grains throughout the slide, but much more freely developed and in larger forms at some places where associated with the green decomposition product above referred to. All the ilmenite is much altered and the smaller crystals are now entirely leucoxene. Apatite occurs, and two much altered areas were once apparently mica. QUARTZ-DIORITES, DIORITES, DOLERITES, AND DIABASE. It is possible that exception may be taken to the manner in which some specimens have been placed in the subdivisions of this group. But the erection and maintenance of hard and fast boundariés, where none such exist in nature, invariably brings the element of personal judgment into play, and in most cases it will be found that ample detail is given to enable the reader to reclassify the specimens to his individual preferences. No pretence can be made that any more than a few, and those the most representative, of the rocks in this group are here given. QUARTZ-DIORITE. M. 11,1. 8S. 26° W. Edd., 17°8 miles. Brownish granitoid rock of medium grain. Texture granitic. Fel- spars clouded light brown, but wherever the structure is not masked by this show very closely repeated twinning. Outside the better defined crystals there is some clearer and probably secondary felspar. Quartz plentiful, traversed by streams of fluid inclusions in two or more directions. The cracks in quartz and felspars alike are iron- stained. Hornblende in short, well-marked, prism forms, pleochroism light brown to rich green, two twinned crystals. Ilmenite occurs both in hornblende and in felspars. A few minute crystals of apatite. (Juartz hornblende diorite. M. 72e. 8S. 23° W. Edd., 19 miles. Pale green rock, with close texture and fine grain, black or very dark green spots of small size. Micro-granitic structure. The minerals are felspar, quartz, horn- blende, magnetite, mica, and augite. ‘The felspars are clear in patches, THE GEOLOGY OF THE ENGLISH CHANNEL. aay but otherwise much clouded, and all are plagioclases. The quartz contains small and moderately numerous fluid inclusions, Hornblende occurs in two forms; some of it is almost certainly an original mineral, and shows good basal sections, with inclusions, however, of other minerals, Elsewhere the hornblende is more fibrous. The mica has suffered considerable change, if I am right in so identifying a very doubtful mineral, and very little unaltered augite remains. Might almost equally well be classed as a quartz aphanite. M. 9e. S. 31° W. Edd., 21'7 miles. Dark grey crystalline rock of rather fine texture. Small felspars of irregular shape and slightly greenish tint, small quartz granules, very clear and bright. The felspars are plagioclase, much clouded in the centre, quite clear around the margins when crystal outline is shown. Some have obviously been broken. In the felspars occur very numerous small prisms and acicular forms of a clear mineral which may be zoisite. Some felspars show an irregular zone of decomposition products a little within the margin. Most of the quartz areas break down in some part to a mosaic of interlocked granules. The quartz contains fluid inclusions. Strain shadows show in both quartz and felspar. Hornblende, chiefly of an olive shade, is freely developed, much is markedly uralitic. A little chlorite occurs. There is some apatite, and a little ilmenite. M. 9r. (Same location as last.) Fine-grained grey rock, felspar and hornblende visible. Plagioclase felspar, somewhat clouded, occasionally achieving good crystal boundaries, and with a marked tendency to zoning from secondary growth, clearer from decomposition than the centres. Re- peated twins somewhat frequent. Minute epidote has been freely developed in many of the felspars, and granules of a mineral which 1s apparently epidote. Fibrous hornblende is a prominent constituent, occurring in large patches, spreading and extending between the felspar areas; principally it is of a green colour with a tendency to blue; here and there brown and olive shades occur, especially in the interior of some of the larger patches. Quartz is fairly plentiful, with numerous small fluid inclusions, most with bubbles, and a few apparently include very small cubic crystals. Some apatite. M. 19a, S. 28° W. Edd., 23°3 miles. Dark greenish grey, granular crystalline. Felspars small and slightly green in tint. Fine grain. Texture micro-granitic. The felspars a good deal clouded with pale brown decomposition products, but with frequent clear patches. Some crystals with characteristic 128 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: microcline twinning. By far the greater part is probably, however, oligoclase. Quartz abundant, in large areas of compound structure. The quartz is traversed by narrow streams of fluid inclusions, and contains small rod-shaped crystals, apparently of apatite. Both massive and actinolitic hornblende occur. The pleochroism of the former is pale yellow-brown, dark olive-green. At places a vivid chlorite replaces some of the hornblende. The quartz is slightly ivon- stained in some of the cracks. Quartz hornblende diorite. Four rocks apparently similar to the group M. 9e., M. 9r., and M. 19a., are— (1) M. 11b. S. 26° W. Edd., 17°8 miles. Dark grey granitoid rock of fine grain. (2) M. 11k. A finer texture of M. 11b. (3) M. 9q. Dark grey, fine grained, felspars greenish. (4) M. 50a. 8S. 16° W. Edd., 30°9 miles. Grey crystalline rock, minutely granular fracture, rather small white felspars somewhat widely scattered. M. 18a. 8S. 29° W. Edd., 23°4 miles. Structure granitic, medium texture, colour grey. Somewhat clouded felspar, apparently plagioclase. Graphic structure in many crystals. Quartz traversed by broad streams of fluid inclusions, some with bubbles; hair-like microlites also occur, and some larger, recognizable, apatite. There are two micas, the one colourless, the other brown and intensely pleochroic, the extreme tint being a very dark bronze green. Quartz mica diorite. M. 58a. 8S. 22° W. Edd., 39 miles. Black and grey granitoid rock, medium grain. Granitic texture. Felspars in the main clear, but here and there clouded with decomposition products. All apparently plagioclase and probably oligoclase. The quartz clear, with small fluid inclusions and, at places, hair-like microliths. Brown and olive-brown mica, strongly pleochroic. Green and olive hornblende, always associated with mica, but on the whole in less quantity. The hornblende and mica inter- penetrate. A fair amount of apatite is present. The rock must be classed as a quartz-diorite, with hornblende as well as mica present. M. 80d. 8S. 163° W. Edd., 48-9 miles. Fine-grained brown granitoid rock, with black mica, texture granitic. Felspar much altered and crowded with brown decomposition pro- THE GEOLOGY OF THE ENGLISH CHANNEL. 129 ducts. A few crystals appear zoned, some still show repeated twinning. Much quartz, in which fluid inclusions are common; a majority of these inclusions have bubbles. Brown mica. Apatite. Some iron- staining. Quartz mica diorite. DIORITE M. 12d. S. 26° W. Edd., 17°8 miles. A striking looking rock by reason of the lustre of its constituent minerals. Very dark in colour, consisting as it does of a black mineral in prismatic form, and a clear felspar. Some of the little prisms of the black mineral are as much as 3 mm. in length. The rock consists of a clear labradorite, in which, however, calcite granules are developed here and there along cracks; and a green monoclinic pyroxene, egirine, in which a very marked schiller structure has been set up, the microlites being of a dark brown. Minute crystals of pyroxene appear in the felspars. Irregular patches of an iron oxide, apparently magnetite, are common. M. 35b. 5S. 32° W. Edd., 18 miles. A fine grained, dark grey, granular rock with much mica. Besides the dark mica there is obviously a lighter mineral, and the two are very uniformly admixed. The section shows this rock to be a mica- ate Rich brown mica occurs freely in irregular plates, and felspar in mosaic. A minority of the felspar granules are striated, a very few show decomposition pro- ducts. An occasional crystal of apatite is present and a fair amount of titanic iron ore in small grains. The general appearance of the rock is very fresh. A similar rock to M 35b. is M. 79a. 8S. 16° W. Edd., 48°7 miles. Dark grey, close textured, much mica in small form. M. 9s. 8. 31° W. Edd., 21°7 miles. A dark coloured rock, the exterior of which shows large lustrous black hornblende and dark drab and brown felspar. Fracture very un- even and texture coarse. The felspars in this rock are now almost indistinguishable as such, an occasional very small patch showing repeated twinning being all that remains unaltered; for the rest they have given place to a granular and fibrous mineral of high refraction and double refraction, and apparently colourless, although the larger grains may have a palest shade of green. The rest of the slide is occupied by fibrous pale green hornblende. Ilmenite is common. ‘The structure ophitic. 130 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: DOLERITE. M. l4e. 8S. 27° W. Edd., 20°3 miles. A fine-grained even-textured rock of a distinct green colour. Some iron pyrites show in the hand specimen. Numerous lath-shaped felspar microlites with irregular terminations, all quite fresh and clear. Pale bluish-green fibrous hornblende is quite the most prominent con- stituent of the rock; there is no general direction pursued by its fibres. Scattered closely throughout the section are very irregular grains of a minutely granular pale brown mineral of strong double refraction when examined with high powers and strong light. Dirty white by reflected hight, this is probably leucoxene. Curious little streams of (?) magnetite occur rather frequently, in forms suggesting that they are reminiscent of some original prismatic mineral. M. 16b. 8S, 29° W. Edd., 20°9 miles. Pale green minutely granular rock. A slide of confused texture. Fibrous green hornblende. Felspar with a tendency to lath-shaped sections. Apparently no quartz. Grain very fine. M. 2le. S. 25. W. Edd., 21°7 miles. A close-textured grey rock, looks much like a grit. The most prominent feature in the section is the abundance of pale yellowish-green acicular or fibrous mineral in diverging bundles, which often have the appearance of having been drawn together at the middle. Here and there almost colourless, at other places this mineral takes a blue-green tint, and it is almost certainly actinolite. These bundles are largely set in a crypto-crystalline ground-mass, which is freely invaded by shorter prisms of actinolite. There are also felspar crystals of irregular outline, some certainly plagioclase, some possibly orthoclase, and micro-porphyritic quartz is about as frequent as the felspar. There is a considerable sprinkling of grains of titanic iron ore. M. 80c. S. 163° W. Edd., 48°9 miles. Clouded white felspars, lath-shaped in part, in part conforming to the interspaces between the augites which constitute the more part of the rock. Portions of the felspars are still quite clear. The augite is in the main quite fresh, but traces of chloritic products occur. Characteristic patches of ilmenite. DIABASE. M. 27a. 8. 19° W. Edd., 18°3 miles. Compact dark grey rock, green felspar and hornblende. Augite, hornblende, chlorite, plagioclase, leucoxene, quartz. The augite, pale THE GEOLOGY OF THE ENGLISH CHANNEL. ou brown, apparently existed in ophitic form; it is now almost entirely replaced by hornblende. The hornblende is chiefly pale green, with a slight blue shade and orange-brown tints along cracks and cleavages. The titanic iron ore is entirely associated with the hornblende, and is present in large forms and branching growths. Chlorite occurs in fairly large areas, and exhibits marked pleochroism from pale brown pink to pale bluish green. The felspars are pale pink, rather fresh in appearance, but sometimes traversed along cleavages by chlorite; they have a tendency to elongated parallelogram section. Quartz shows good crystal outline. M. 14v. 8S, 24° W. Edd., 20 miles. A small hard pebble, distinctly green in colour, and having small somewhat vesicular looking cavities on the surface. In section, seen to be a network of small lath-shaped felspars set in a grey and green ground-mass. Chlorite is disseminated throughout the slide, and the larger patches, which are not infrequent, are evidently after augite, as they are associated with unaltered remnants of the latter mineral. Calcite occurs, not only mingled with the ground-mass, but also in larger patches; the solution of these has probably left the cavities on the surface of the pebble. There are two or three recognizable crystals of ilmenite and scattered black grains that are either this mineral or magnetite. M. 15c. S. 27° W. Edd., 20°3 miles. Greenish hornblendic rock. Large patches of very pale hornblende. Between these a fibro- granular ground-mass of low double refraction, prismatic and basal sections of zoisite of sufficient size for discrimination occur rather freely. Some iron ore. What other minerals may be present in minute forms cannot be determined. Zoisite-amphibohite. M, 22c. 8. 25° W. Edd., 21°9 miles. Dark green rock, massive hornblende. Shows a very little felspar, and a few patches of augite. In the rest it consists of reedy hornblende of very varying tint, from almost colourless to olive-brown and blue-green, all in light shades. GRANITOID ROCKS M. 31. S. 25° W. Edd., 15 miles. Granitic tecture. Brown and black, ditto brown. Felsitic. Brown, fine-grained, granular. La2 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: M. 36. 8S. 37° W. Edd., 17°5 miles. Granitic texture. £ Medium grain, white felspar, black mica. g. Fine grain, pink, black specks. Felsitic texture. %. Brown, granular. M. 33. S8. 25° W. Edd., 17°5 miles. Diorite. M. 11, M. 12, M. 13. 5S. 26° W. Edd., 17°8 miles. M.11. Granitic texture. g. Fine-grained brown, black mica. M. 12. Hornblende Diorite. Granitic texture. Red with abundance of mica. Brown of fine grain. Brown of medium grain. Grey. M. 35. §. 32° W. Edd., 18 miles. Granitic texture. f£. Brown. M. 27. 8S. 19° W. Edd., 18°3 miles. Granitic texture. Pale grey. M. 26. 8. 20° W., 18°4 miles. Two quartz-hornblende-diorite pebbles. M. 34. S. 28° W. Edd., 18°5 miles. Felsitic texture. g. Brown, fine granular. M. 72. 8S. 23° W. Edd., 19-0 miles. Granitic texture. Medium grain, grey and brown, brown mica. Brown. Red with black mica. Felsitic texture. ¢. Porcellanous cream-coloured. M. 14. S. 24° W. Edd., 20 miles. Granitic texture. ik. Red medium grain, and several other varieties. Felsitic texture. +. Close-grained buff. M. 15. S. 27° W. Edd., 20:3 miles. Granitic texture. Coarse-grained, white felspar, yellow-stained, black mica, much like boulder from 8.W. by 8S. $ 8. Bolt Head, 19 miles. Fine-grained grey, brown and silvery mica. Brown with white mica. M. 20. 8S. 25° W. Edd., 20°5 miles. Granitic texture. f. Black and white, rather coarse, some hornblende. e. Black and buff, fine grained, (?) some hornblende. M. 16. S. 29° W. Edd., 20°9 miles. Granitic texture. Distinctly granitic in appearance, flesh-coloured felspars, orthoclase twins, quartz. Grey and brown, fine grained. M. 21. S. 25° W. Edd., 21°2 miles. A few grey granitic rocks. THE GEOLOGY OF THE ENGLISH CHANNEL. hoo M. 30. 8. 21° W. Edd., 21°5 miles. Granitic texture. a. Coarse, pale cream-coloured, dark mica. M.9. 8. 31° W. Edd., 21°7 miles. Granitie texture. 1. Medium grain, red felspars. m. Medium grain, buff felspars. r. Fine-grained grey. Medium grain, brown and black. M. 40. 8. 38° W. Edd., 21°7 miles. Granitic texture. Brown, medium grain. Felsitte texture. Brown, granular. Greenish grey. M. 22. S. 25° W. Edd., 21°9 miles. Granitic texture. b. Buff and brown felspar, black hornblende, medium texture. M. 24. S. 24° W. Edd., 22°5 miles. Felsitic texture. ¢. Pale grey, compact, white mica. Red. M. 25. 8. 24° W. Edd., 23 miles. Granitic texture. b. Brownish, fine grained, (?) hornblende. M. 19. 8. 28° W. Edd., 23°3 miles. Granitic texture. . Dark grey, fine grained, much dark mica. M. 18. 8S. 29° W. Edd., 23°4 miles. Granitic texture. Brown and grey, medium grain, pale grey felspars. M. 43. S, 21° W. Edd., 28°8 miles. Felsitic texture. Brown-grey, granular. M. 77. S. 11° W. Edd., 38°8 miles. Granitic texture. Brown, very fine grain. Light brown, fine grain, black mica. M. 58. S. 22° W. Edd., 39 miles. Granitic texture. The granitoid rocks occur in rather large pebbles, almost small boulders. Grey, rather coarse, clear felspars, black mica. Grey, rather fine, clear felspars, black mica. M. 62. 8. 25° W. Edd., 46°4 miles. Felsitic texture. c. Compact, greenish grey, with pink felspars and porphyritic quartz. d. A somewhat similar rock, more granular, felspars white, some hornblende. Also, pink, saccharine texture. 134 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : M. 80. S. 165° W. Edd., 48°9 miles. Granitie texture. Brown-grey, fine-grained, black mica. Felsitic terture. Light brown-grey, black mica, apparently a variant of above. All the above granitoid rocks are described from megascopic ex- amination only, and the lst is inserted chiefly in order to point out the localities in which this class of material has been found. To adequately deal with all the varieties a great number of sections would have been required, but probably those which have been microscopically examined give a fair general idea of the whole. SCHORL ROCK. Rocks consisting of tourmaline and quartz; placed here, although undoubtedly in a sense metamorphic, on account of their usual associa- tion with granite. 356/4a. W.45. Bolt Head, 4? miles. A rather small pebble. This rock consists of quartz and tourmaline. Much of the quartz is secondary ; in part it forms a mosaic, in parts it extends from original erystals with which its crystal axis corresponds. The primary quartz contains fluid inclusions with bubbles, the bubble in many instances occupying more space than the fluid; these inclusions are very numerous and rather large. The secondary quartz contains few and very small fluid inclusions. Acicular schorl is scattered throughout the slide, sometimes in almost fibrous radial bunches, at others in slender, well-defined prisms, radially or otherwise arranged; there is also some more massive schorl. The colour is chiefly hght blue to rich blue, but blue-green occurs, and occasionally olive-brown. M. 3la. S. 25° W. Edd., 15 miles. A schorl rock of Dartmoor type. Ground-mass a quartz mosaic. The quartz contains many fluid inclusions, some of which, in addition to a bubble, have also cubic crystals in the fluid. These cubic crystals are, in fact, very common. The slide is crowded with granular tourmaline, chiefly a very dark brown colour, almost opaque, but a few grains are blue-green. M. 31g. Schorl rock. The general ground of a brown shade, an intimate mixture of rather pale brown tourmaline and quartz. Frequent areas of quartz partially invaded by acicular tourmaline. Some cracks are also filled by quartz. The quartz areas all present a mosaic, in which some grains contain many more fluid inclusions with bubbles Journ. Mar. Biol. Assoc, Vol. VIII. Plate VII. 354/1. N.W. by N. (mag.) Fdd., 3 mile. Hornblende gneiss, with garnets. Ordinary light. x 14%. Fie. 2. M. 62a. S, 25° W. Edd., 46:4 miles. Crushed plagioclase felspar in chlorite schist. Crossed nicols, x 29, To face p. 135. THE GEOLOGY OF THE ENGLISH CHANNEL. 135 than do others. Small cubic crystals are not infrequent in these inclusions. Schorl rock also occurs at 36a, 8. 54° W. Edd., 17:5 miles ; 72, 8. 23° W. Edd., 19 miles ; 14f, 8. 41° W. Edd., 20 miles. ANDESITES. 354/4b. 63 miles W. from Rame Head. Strictly speaking a felsite. Red-brown felsitic ground-mass, with porphyritic orthoclase, quartz, and dark mica. One of several pieces here dredged, with every indication of being practically in situ. Is much like the andesitic felsite of Withnoe, but lacks the flow structure sometimes present in the latter. The similarity of the specimens to many, however, which have been collected at Withnoe practically amounts to identity. Thus to the Cawsand mass and the two near Withnoe we have to add another, and a submarine, patch of igneous rock of the New Red Sandstone period. Apparently this exposure is of some considerable area. A conglomerate containing large frag- ments of this rock was taken in the same dredging. M. 15a. 8S. 27° W. Edd., 20°3 miles. Brownish-grey trachytic rock. Well-marked flow structure. Ground-mass a devitrified glass (pala- gonite). Some augite developed in rare crystals and crystalline areas. Flakes of very dark brown mica rather frequent. Lines and micro- dendritic growths of iron ore (?) hematite. Occasional patches of calcite. M. 15. Also yielded a more red variety of the above. GNEISS. Some latitude must be allowed in any classification which attempts to discriminate Gneiss from Schist in this area. If anything, the writer leans toward identification as the former in doubtful cases. 354/1. N.W. by N. Edd., § mile. A large stone or small boulder, angular with freshly fractured surface. A grey-green foliated rock with plates of brown mica and numerous garnets up to 1°75 mm. in diameter. Quartz fills thin joints at right angles to the planes of foliation. The mica is so developed as to give to the rock an easy cleavage. The pale-pink garnets are a characteristic feature; these are much cracked, and around them bend the less resisting minerals. There is much blue-green actinolitic hornblende, the blades of which all approximately conform to one direction. Mica is in much less quantity than would appear from the hand specimen; it is intensely pleochroic, from pale straw-colour to dark cinnamon-brown; its occurrence is practically limited to the neighbourhood of the garnets. NEW SERIES.—VOL, VIII. NO. 2. K 136 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : Touching and partially enveloping the garnets is a certain amount of chlorite. Water-clear felspar in mosaic form fills all interspaces; it appears to be albite, and inclusions of apatite are frequent. There seem to be some rare fragments of pale brown-augite. (Plate VI, fig. 1.) 354/3f. Hand Deeps. A schistose or foliated rock, dark steel-grey in colour, and highly lustrous from the abundance of pale mica. Rare eyes of red felspar occur. The section does not pass through any of the felspar eyes. There is a distinct banded structure: bands in which hornblende predominates, bands consisting almost entirely of white mica, bands of felspar mosaic. But in every layer there is some slight admixture of the other minerals. The hornblende is both uralitic and actinolitic with very distinct indigo tint here and there. It is not entirely free from chlorite. The mica appears perfectly fresh and shows no trace of pleochroism. Both hornblende and mica exhibit a parallelism of arrangement. The felspar is apparently albite, quite clear, with apparently a casual grain of quartz. Grains of sphene are not un- common. 355/1. West side of East Rutts. A brown stained schistose or gneissic rock, exhibiting much contor- tion. No part of the slide is entirely free from iron stain. Contorted bands of limonite traverse it, and these appear to have been developed at the expense of mica, bleached residual blades of which are associated with it. All the mica is much bent. Parallel with, and touching the limonite, are narrow interrupted bands of calcite. The general ground-mass is a mosaic of slightly stained clear minerals, and apparently consists of albite (?) and quartz in about equal proportions, the quartz showing fluid inclusions with bubbles, and the albite being rather frequently twinned. M. 36p. S. 37° W. Edd., 17°5 miles. A mica schist or gneiss, shows clear felspar, some in moderate-sized crystals, and mica which is in general rather silvery but in small patches dark bronze. There are two orders of felspar, the one represented by slightly clouded crystals of irregular outline and exhibiting signs of crush, the other present in mosaic form. The repeated twinning of plagioclase appears almost constantly in the former, but not at all in the latter. And some few of the larger crystals extinguish differently in different zones, although there is no appearance of zonal structure except THE GEOLOGY OF THE ENGLISH CHANNEL. 137 between crossed nicols. The mosaic in places is of larger and irregular granules, in places of small granules of lenticular form the longer axes of which le parallel to each other and form lines flowing round the crystals of the first order. The mica conforms in general direction to these same lines, it shows moderately strong pleochroism, and its face colours range from rich cinnamon-brown in basal planes to a rather pale olive-brown in sections perpendicular to these planes. A very little apatite is present. M. 16a. 8S. 29° W. Edd., 20-9 miles. Schistose rock. Dark grey and pale brown, lamination very clearly defined ; fissile. Much dark grey mica on joint faces. Structure schistose. Irregularly bounded felspar areas occasionally associated with quartz form “eyes,” around which the other minerals are bent. These felspars are all much clouded; some are thickly set with microlites, but polysynthetic structure is clearly discernible in many instances. Most of the felspars are curiously isolated from their surroundings and have a rounded form, as though due to friction. White mica is abundantly developed, forming streams in which the felspars appear as islands. Mingling with the mica is dull green horn- blende in short blades and in grains. There are numerous long patches and irregular areas of quartz mosaic, the quartz containing some apparently fluid inclusions, prismatic microlites, the larger of which are seen to be hornblende, and rather frequent blades of the latter mineral. The mica does not appear to invade the quartz areas. Apatite is fairly plentiful. There is occasional staining by iron oxide, especially between the quartz grains and the blades of mica. This rock is a gneiss, and has evidently been subjected to extreme pressure. M. 9k. S. 31° W. Edd., 21°7 miles. A grey gneiss. Schistose structure well marked. Somewhat clouded felspars appear to form the only remaining original mineral. These show plagioclase twinning; some have been broken across with the development of a felspar mosaic along the line of fracture. There are two orders of mosaic structure, the one coarser and composed of a very clear mineral, the other much finer and containing minute hornblende and apparently zoisite. For the more part the large felspars are surrounded by this finer material, into which they have the appearance of having been driven. Ilmenite, hornblende, and zoisite mark out the planes of schistosity. The hornblende is almost entirely in minute blades and needles of a bright blue-green. Prisms of apatite are frequent in the 138 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : mosaic. Of this mosaic, which is probably almost all felspar, it should be noted that the coarser part is formed of entirely irregular inter- locking granules; in the finer part the granules all appear lenticular, and their longer axes conform to the planes of schistosity. From M.9 a coarse gneiss was also noted, and M. 36q is but a slight variant of M. 36p. M. 25c. S. 24° W. Edd., 23 miles is a coarse gneiss with white opaque felspar and grey-green chlorite. SCHISTS. MICA SCHIST. 354/3/e. Hand Deeps. A mica schist in which micaceous layers greatly contorted and con- voluted alternate with granular layers of quartz and garnet. This rock has not been microscopically examined. Fie. 1. Mica Schist from Hand Deeps. Y > 7 WEE 5 aie = LE gets 7] LP fe We. ‘Lge Na GE A W ay M. 31f. 8S. 25° W. Edd., 15 miles. A grey schist of very fine grain, traversed by rather broad lighter- coloured bands. The section shows a distinctly foliated rock, the lighter parts are a clear quartz mosaic; I can detect no felspar; the quartz shows numerous fluid inclusions, some with very small bubbles. The darker parts appear to consist of a scaly mica of a yellow tint, associated with which is a little limonite and black granular matter which inay be carbonaceous. M. llx. S. 26° W. Edd., 17°8 miles. Micaceous schist, the planes of schistosity well marked by lustrous bronze mica, cleaves very perfectly. The section shows, in addition to mica, a granular mosaic, which certainly in the main consists of quartz but also contains felspar, which latter can only be detected by its biaxial figure in convergent light. The quartz has, in the larger grains, fluid inclusions with bubbles. The mica is of a rich brown colour, but some few rather well-developed crystals are colourless. The basal sections show numerous acicular microlites, and also very dark brown patches, almost opaque, surround- ing small crystals which are apparently zircon. THE GEOLOGY OF THE ENGLISH CHANNEL. 139 M. 9c. 8. 31° W. Edd., 21°7 miles. A schistose rock of light brownish-grey colour and rather pearly lustre; small darker spots mark an “eye” structure. The general body of the rock is crypto-crystalline, polarizing in low tints. Streams of mica in minutest scales are developed in this ground-mass, especially near the “eyes,” which largely consist of this mineral associated with a felspar mosaic in which some granules are large enough for identification. The basal planes of the mica follow one general direction throughout the slide. The dark colour of the “eyes” arises from irregular plates, aggregates of an olive-brown sub- stance with moderate double refraction, but this may be somewhat masked by the colour. M. 43a, 8S. 21° W. Edd., 28°8 miles. A thin pebble of dark grey schist. A minutely granular rock, consisting of quartz, felspar probably all plagioclase, white mica (sericite), epidote (?), chlorite, and traversed by a vein of calcite. Apatite is present in some quantity. The felspar granules freely exhibit the repeated twinning of plagioclase. M. 20g. S. 25° W. Edd., 20'5 miles. Closely resembles M. 11x, but the mica has a more decidedly bronze lustre. In both these rocks there are stray features of resemblance to the series from the immediate locality of the Eddystone. M. 3lc. 8S. 25° W. Edd., 15 miles. Rather like a fine-grained granitoid rock, now stained brown by exposure, but fissile from the development of silvery mica along definite planes. M. 36c. S. 37° W. Edd., 17°5 miles. Largely quartz, but with possibly some felspar, silvery mica chiefly confined to the cleavage planes, which are stained pink with iron oxide. A very fissile rock. CHLORITE SCHIST. Off Stoke Point. A silvery-green schist, consisting of vivid blue-green chlorite changed here and there to a dull orange, at which places it exhibits a moderate double refraction, and water-clear felspar in which no repeated twins are observable (the section is small). There is also apatite, and much of a granular dusty brown mineral, buff coloured by reflected light, leucoxene. 3096/1. 4to5 miles 8. } E. from Prawle Point. A chlorite schist with bands of quartz one-eighth of an inch in width. 140 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : 356/2. 3 miles §.S.E. 4 E. from Prawle Point. A silvery grey chlorite schist with minutely wrinkled surfaces of chlorite precisely like the shore rocks. Much chlorite. These last three specimens are practically identical with rocks to be found in sitw on shore in the Start Point to Bolt Tail district. None of the specimens show signs of travel or weavr. M. 62a. 8. 25° W. Edd., 46°4 miles. A mixture of felspar and quartz, largely the former. Micro-mylonitic structure well developed and some of the felspars greatly deformed. One in especial, with well-marked plagioclase twinning, is much bent in reverse directions, is cracked, and finally at each end passes into mylonite. The slide is full of similar evidence of deformation. As a whole the felspar has a reddish tinge; some portions are crowded with microlites of high double refraction, probably calcite. Calcite is rather freely developed, filling interspaces and cracks. Chlorite plays a similar part, and the two are associated. In places the chlorite is thickly strewn with minute grains and blades of a feebly translucent brown mineral. If the presence of original felspars is to be the criterion this rock should have been included among the gneisses. (Plate VII, fig. 2.) HORNBLENDE SCHISTS WITH AUGITE. 356/4/b. W.48. Bolt Head, 4? miles. A very compact dark greenish-grey schist with occasional small specks of pyrites. The slide looks distinctly patchy, augite areas of brown tint, and granular augite. Much uralitic hornblende, blue in ordinary light, with a faint tinge of green, pleochroism brownish grey to blue-green. This mineral dominates the section. Much calcite, with a tendency to form broad bands. And, filling irregular interspaces, a mosaic of water- clear granules, containing both felspar and quartz. Calcite mingles with this mosaic. A little leucoxene occurs. M. 80b. S. 163° W. Edd., 48-9 miles. Fine-grained dark grey rock; some pyrites. Structure schistose. Marked in part by veins of secondary quartz in mosaic. The felspar is entirely clouded with decomposition pro- ducts; it les irregularly mingled with very pale green fibrous horn- blende. The latter has apparently developed at the expense of a pale pink augite, of which a fair quantity remains; in turn the hornblende has here and there given place to chlorite. Irregular grains of a feebly translucent mineral, probably leucoxene, are plentiful, and have a dis- tinct tendency to linear arrangement. THE GEOLOGY OF THE ENGLISH CHANNEL. 141 CALC SCHIST. M. l4r. S. 24° W. Edd., 20 miles. A compact rock with well-marked cleavage, the planes of which are not, however, closely set. Broken across the cleavage, the colour is a warm grey and the texture close and uniform. The cleavage planes show a somewhat pearly lustre and are stained in parts with red oxide of iron. The rock gives distinct effervescence with cold acid, with warm acid effervesces freely; fragments retain their form, however, but from the surface a few small quartz grains are set ree: The section shows numerous clear grains set in granular cement, with which, in places, is much red oxide of iron. Colourless mica (sericite) is rather sparingly developed, being more prominent on the cleavage planes. The clear grains are quartz, with the very rare exception of a felspar, and many show boundaries imposed upon them by the adjacent calcite and dolomite, which freely exhibits the rhombus form of larger or smaller dimensions. The granular cement consists, in fact, almost entirely of minutely crystalline dolomite and calcite, a high power being required to detect the crystal forms. A very large proportion of the quartz grains show secondary enlargement, the secondary quartz having the same crystal axes as the original grain. The boundary between the original and secondary is just such a dark line as occurs when a mineral of greater refractive index is enclosed in a mineral of less. MHair-like microlites are not uncommon in the primary quartz, but none pass over into the marginal secondary growth. In the loose powder obtained by treating this rock in hot acid I found one small crystal of tourmaline. The fact that the rock retains its form after treatment with hot acid shows that neither the iron nor the dolomite are necessary cements, the secondary quartz being in itself sufficient. Presumedly it is best to call the specimen a caleschist. SERPENTINE. M. 24h. A small jet-black pebble with very smooth surface. The section shows yellowish-green serpentine with “lattice” structure, traversed by roughly parallel streams of dense black material, which also occurs irregularly in cracks of varying direction, and more or less densely diffused in certain parts of the slide over areas which appear reminiscent of the original structure of the rock. The serpentine varies considerably in its depth of shade. At one point it is blue-green around the margin of a clear mineral, which appears possibly to be a plagioclase felspar. 142 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : The serpentine, some of which is colourless, splits up under crossed nicols into doubly refracting bands and isotropic portions. The association of felspar with a massive serpentine is rare, but Professor Bonney has recorded an instance from the Lizard district. This specimen acquires some value, despite its small size, since in Hunt's series there occurs a serpentine boulder, H. 6, of 5 cwt. QUARTZITES. A number of quartzites, very similar to some in the Budleigh pebble-bed, have been dredged from a great many stations. Up to the present no fossils have been found in them. These rocks vary in colour, being purple, red, light red, buff, grey and white, and are associated with very hard grits which have not been sufficiently examined. M. 80. 8. 163° W. Edd., 48°9 miles. Purple quartzite, very compact in structure. Quartz grains, sub- angular and of very uniform size, fluid enclosures common. The cementing material silica with much iron oxide; this cement appears to be minutely granular. An occasional quartz grain shows hair-like microlites. This may be taken as a type. Other Purple Quartzites were dredged at Stations M. 31, M. 36, M. 13, M. 35, M. 27, M. 26, M. 34, M. 29, M. 14, M. 20, M. 9, M. 40, M. 22, M. 25, M. 43, M. 50, M. 67, and M. 80. Red quartzites from M. 11, M. 72. Light red quartzites from M. 13., M. 30. Buff quartzites from M. 34, M. 20, M. 22, M. 41, M. 43. White quartzite from M. 21. M. 1lf. 8. 26° W. Edd., 17°8 miles. A grey grit. A little mica appears in the section. The rock is practically a quartzite. SEDIMENTARY ROCKS. Under the heading of sedimentary rocks have been included all altered varieties, except such as may possibly have been fully meta- morphosed to schists and quartzites. CARBONIFEROUS AND EARLIER. SANDSTONES AND GRITS. 304/4k. 6} miles W. from Rame Head. A red micaceous grit, probably Devonian. M. 9b. S. 31° W. Edd., 21°7 miles. A light brown sandstone of flaggy structure, bedding marked by slight variations of tint. Possibly Devonian. #25” Journ. Mar, Biol. Assoc., Vol. VIII. Plate VIII. M. 9d. S. 31° W. Edd., 21:7 miles. Grit, showing large grain, A—B. Ordinary light. x 29, M. 9d. S. 31° W. Edd., 21-7 miles. Grit, showing compound structure of grain ; at end A striated felspar, at end B quartz mosaic. Crossed ivicols, x 29, To face p. 148. THE GEOLOGY OF THE ENGLISH CHANNEL. 143 M. 9d. A rather light grey rock, which appears to be a compact and very fine-grained grit; looks much like many grits of the Devonian age. The microscope confirms preliminary examination; this rock is a grit of close texture. A considerable proportion of the granules are felspar, many showing repeated twins. A number of the grains prove to be of compound structure, and are portions of quartz and felspar mosaics from some original schist or gneiss. Further than this, three of the larger grains are compounded of portions of felspars with bent striation and portions of quartz mosaic, being, in fact, derived microscopic specimens of gneiss. As bearing on the age of the rocks which have supped the fragments. this slide is distinctly interesting. The interstitial matter largely con- sists of a rather pale chlorite in which occur rare blades of pale mica, There is some ilmenite, apparently detrital. (Plate VIII, figs. 1 and 2 ) M. 11f. S. 26° W. Edd., 17°8 miles. A fine grey grit slightly browned by exposure. Much lke last in general appearance, and may well be of Devonian formation, already included as quartzite, the cement being apparently silica. The grains are sub-angular and include a few felspars. There are rather numerous grains of sphene, some irregular, some of the characteristic lozenge shape, all apparently derived. Grits, not microscopically examined, were also taken at M. 31, M. 27, M. 26, M. 14, M. 20, M. 16, M. 9, M. 40, M. 19, M. 41, M. 77, and M. 80. SLATES. Unaltered slate was scarce, as might be expected from the fact that it would usually be associated with much harder material, and probably be soon destroyed. M. 77a. 8. 11° W. Edd., 38°8 miles. Dark compact shale, a clay slate. Under the microscope appears built up of minute grains of high double refraction. There are frequent traces of minute organisms, some possibly foraminifera. Some shell fragments still consist of car- bonate of lime, and numerous forms of circular section are infilled with calcite. M. 39. 8S. 38° W. Edd., 21°9 miles. A decomposed slate. ALTERED SLATES. 354/4j. 63 miles W. from Rame Head. A slate of Devonian type, evidently altered by the proximity of the ~ andesite dyke which here occurs. 144 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : M. 14j. 8S. 24° W. Edd., 20 miles. Almost black, a very compact rock with sub-conchoidal fracture, and lustre somewhat like a quartzite. The worn surface shows rather minute banded structure. The same banded structure shows in section when examined by the unaided eye, but is less prominent under the microscope; this is a sedimentary rock altered by contact metamorphism. The general ground-mass is a crypto-crystalline substance, rising to a minute mosaic here and there, and probably having a complex mineral com- position. Felspar almost certainly plays an important part. In this there occur small grey-clouded areas, presenting sections which are chiefly of somewhat ill-defined rhombus shape, and which in certain positions completely extinguish. One such area has a portion clear of dusty products, and this shows high double refraction in a bright and pure colour; other similar instances occur. The dusty material shows a tendency to arrange itself in zones and crosses, and from examina- tion of a great number of these imperfect crystals there can be no doubt that the rock is crowded with andalusite in a condition bordering on the chiastolite form. For the rest, there is much small brown mica, and titanic iron ore, mostly in very small grains, is quite plentiful. Such a rock might easily arise from the metamorphism of a Devonian or Carboniferous slate by contact with a large boss of igneous material. Altered slates, having the appearance of being baked by proximity to igneous rock, were also taken at the following stations, but have not been examined microscopically. M. 11, M. 34, M. 72, M. 14, M. 15, M. 21 (common), M. 24 (very common), M. 17, M. 18. LIMESTONE. M. 26b. 8S. 20° W. Edd., 18°4 miles. A blue-grey limestone, veined and mottled with lighter calcite, much like some of the South Devon middle Devonian series. Consists almost entirely of irregular interosculating calcite patches, traversed by cracks filled with clear calcite. The calcite forms give indication of former organic remains, and at three places undoubted sections of madrepore occur. Around and between the boundaries of some of the calcite areas are very irregular and much folded lines of a granular black substance, apparently carbonaceous. NEW RED SANDSTONE. CONGLOMERATE. 304/3b. Hand Deeps. A red conglomerate, certainly of the New Red Sandstone period. Among the derived constituents are quartz grains of some size THE GEOLOGY OF THE ENGLISH CHANNEL. 145 showing mosaic structure and containing fluid inclusions with bubbles. Other grains of felspar mosaic precisely similar to that occurring in the neighbouring schists and gneisses. Blades of mica that may have been similarly derived. Quartzites, and fragments of highly cleaved slates, or very fine-grained schists. Calcite or dolomite, probably the latter, is very prominent, filling the interspaces. 354/4b. 63 miles W. from Rame Head. Conglomerate with fragments of andesite. SANDSTONE. 354/3c. Hand Deeps. A coarse, red, micaceous sandstone. 304/2a. S.W. Edd., 2 miles. Variegated sandstone, fine texture, red and grey. 354/2b. Buff sandstone, almost salmon coloured. 354/2c. Fine-grained compact red marly sandstone, sub-jaspideous. M. 31. S. 25° W. Edd., 15 miles. Red sandstone and buff sandstone. M. 32. 8. 25° W. Edd., 16:3 miles. Red sandstone and yellow sandstone. M. 10. S. 26° W. Edd., 178 miles. Red sandstone. M. 33. 8. 25° W. Edd., 17-5 miles. Red sandstone. M. 34. S. 28° W. Edd., 18-5 miles. Variegated, red and grey. M. 27. §. 19° W. Edd., 18-3 miles. Red sandstone and buff sandstone. M. 26. 8S. 20° W. Edd., 18-4 miles. Red sandstone. M. 40. 8S. 38° W. Edd., 21-7 miles. Variegated, red and grey. M.17. S. 28° W. Edd., 23-3 miles. Red sandstone. M. 19. S. 28° W. Edd., 23-3 miles. Red sandstone in large angular blocks. M. 18. 5S. 29° W. Edd., 23-4 miles. Red sandstone. 146 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: M. 2ig. 8S. 25° W. Edd., 21-2 miles. (Not inserted in the above series because structurally different; all the above are of ordinary type.) A compact rock with granular fracture; the granules vary from buff to a light brown with a tinge of Indian red. The rock has been bored by molluscs. A sandstone cemented by crystalline calcite, dolomite, or in the alternative a very sandy crystalline limestone. The quartz grains well rounded with numerous, and some large, fluid inclusions. One grain which proves to be part of a quartz mosaic contains a fragment of rich brown mica. Yet another grain contains brown mica, and many have acicular microlites, possibly apatite. Considerably less numerous than the quartzes are felspar grains, both orthoclase and plagioclase. There are numerous fragments of a brown rock, apparently a palagonite, containing some crystals, including mica. The rhombs of dolomite are clearly marked out by concentric bands of dark brown inclusions, grains, and microlites, which tend to form radial bunches. In some cases the centre of a rhomb is completely darkened. MARLS. Under this heading are included hard marly limestones, those more exceptional forms from the Trias which are calculated to resist abra- sion; with them is a smaller percentage of the true friable marl. M. 34b. 8S. 28° W. Edd., 18°5 miles. A dark red pebble, with smooth surface, much bored by molluses, A cut surface shows very compact rock, the red colour of which is slightly mottled by a lighter shade. In the section this mottling is much more prominent. The rock is minutely granular, the mineral being probably a mixture of calcite and dolomite. There are also small angular fragments of quartz, and apparently some fibres of gypsum. Some of the borings have been infilled with secondary sand- stone having calcareous cement. The stone is a very hard marl. M. 9f. 8. 31° W. Hdd., 21°7 miles. A fine-grained red marl. Much very fine sand, with some larger quartz grains. The colour not uniformly distributed but mottled with grey. Many of the grains appear to be crystalline calcite or dolomite. M. 31. S. 25° W. Edd., 15 miles. Soft variegated marl, red and green. M. 36. S. 37° W. Edd., 17°5 miles. Hard chocolate-coloured marl. THE GEOLOGY OF THE ENGLISH CHANNEL. 147 M.11. S. 26° W. Edd., 17°8 miles. Hard chocolate-coloured marl. M. 12. S. 26° W. Edd., 17°8 miles. Hard chocolate-coloured marl. M. 35. S. 32° W. Edd., 18 miles. Hard chocolate-coloured marl. M. 34. 8S. 28° W. Edd., 18°5 miles. Hard chocolate-coloured marl. M. 14. §. 24° W. Edd., 20 miles. Hard chocolate-coloured marl. M. 15. S. 27° W. Edd., 20°3 miles. Pale red, rather soft marl. M. 20. 8S. 25° W. Edd., 20°5 miles. Hard chocolate-coloured marl. M. 24. S. 24 W. Edd., 22°5 miles Hard chocolate-coloured marl. LIMESTONES. The following dolomitic limestones would appear to belong to the New Red Sandstone formation. M. 34d. S. 28° W. Edd., 18°5 miles. A rather small brown-grey pebble, much bored by saxicava. Freshly broken surface is pale brown, and shows somewhat granular, very uniform, texture. The section, examined by the unaided eye, suggests a slightly marked banded structure. The matrix of the rock is a fairly pure crypto-crystalline calcite and dolomite, and minute zoned rhomboids of the latter mineral occur sparsely. But it is so closely set with small sand grains that it might almost be described as a sandstone with cal- careous cement. Most of these clear grains are probably quartz, but some show the repeated twinning of plagioclase felspar. A little brown mica is to be found, and rather numerous rich brown and black specks, which may be rutile. There are also many pale olive patches, distinctly larger than the other granular constituents, some- what ill defined in outline and apparently calcareous. The calcareous ground-mass has here and there a yellowish-brown tint. M. 35e. S. 32° W. Edd., 18 miles. A very similar rock to the last described. M. 2la. S. 25° W. Edd., 21:2 miles. A compact horny-textured rock distinctly hard, but bored by 148 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: molluscs, ete. Colour of broken surface brown with a shade of purple, and buff. Weathered surface an uniform light brown. A granular crystalline limestone, stained by iron in patches and lines. Apparently it has always contained some free spaces which are lined with larger crystal grains. Occasional almost complete rhombs of dolomite of small size occur. There are slight streams of a pale brown mineral of low double refraction; and scoriaceous looking inclusions of rich brown rock, containing small quartzes; these are the more aluminous parts of the rock. PASSAGE BEDS—TRIAS TO RHAETIC. M. 29a. S. 14° W. Edd., 19°8 miles. A coarse, open-textured marl or marly limestone, drab coloured. The section shows widely varying colour and texture, giving at first sight the effect of a detrital rock with many derived fragments. That there are fragments of other marly limestones does indeed appear to be the fact; certain textures associated with definite colours, and with mineral forms not found generally distributed throughout the slide, are located in areas with well or less clearly defined boundaries. On the other hand, the same yellow iron stain which marks some of these areas runs irregularly across the section in a contorted and divided stream and is always associated with a finer ground-mass than the average. In the general body of the rock, besides much granular crystalline calcite, occur small spheroids of a clear mineral, which consist of fibres radially arranged, and are also marked by a slight concentric zoning. One long vein shows the same structure, and its outline is botroidal. This mineral is soluble in HCl. There is a fair amount of dark material, which may be carbonaceous. Not infrequent quartz grains. And in the rather ill-defined orange-brown inclusions (if inclusions they are) a fibrous mineral in single blades showing a double refraction considerably less than that of mica; none of this is to‘be found in the residue after solution in acid, and it may be gypsum. One piece of certain mica is visible, with pleochroism from colourless to cinnamon- brown. The residue after solution in acid consists chiefly of a rich olive-brown isotropic matter in flocculent form. M. 29b. Compact, smooth, and fine-textured marl in thin slabs, can be marked by thumb-nail, drab coloured. The section shows very minute grains of calcite, and some brown fragments which may once have been mica. M. 29c. Angular fragment of stone-coloured marl, rather coarser than last, but still fine-grained and compact, just harder than the thumb-nail, THE GEOLOGY OF THE ENGLISH CHANNEL. 149 M. 29d. Much like last, but has a greenish tinge. M. 29e. Like last, but harder and greener. M. 29f. Like last, but considerably softer, and greener still with patches of bright decided colour. Micaceous. M. 29¢. Green marl and drab-brown marl as above in narrow alternate bands. M. 29h. A layer of coarse grey marl and one of fine-grained drab-brown marl. The series M. 29a. to M. 29h. inclusive indicates a locality occupied by soft marls of varying texture and colour, associated in one and the same formation in layers of varying thickness, the alternations being frequent and repeated. RHAETIC AND LIAS. LIMESTONE AND SHALE. Most of these limestones contain argillaceous matter; some, how- ever, appear to resemble the White Lias; in the absence of field work it is not well to attempt to do other than group Rhaetic and Liassic together. OFF LYME REGIS—in situ. This type rock is frequently dredged off Lyme Regis“? The speci- men shows coral fragments, including Gonioseris. For the rest it is a rough, somewhat sandy limestone, inclined toward a marl. , eS ges - cs © = ‘> “E'S ZaAwAd ARRAN o% ~ ‘ ¥ ms ole ae zt SPE : = a —_ .f OKs Plate XIII. 5 ? SCALE OF NAUTIC MILES STONES FINE CRAVEL N 4 3 2 (2) ART To FHA 9 g 5S 5 \y = re SHELL CRAIEL ay HD. : on ~ _RAME LO, ao £0 FA, - a) Q N) S Q = = Q z KS % R Spat % : e S My % & BS ac) o =! 7 CaCO; 17-41 AVERACE GRADES 6:97 1} i pre oad a Penna n., ‘ \ "Sete « eee} g oo : wa. Cn eS : .. =, a\e Sy ‘ ww =a : \ sev = Ne ay = Qn YUN aS = AT THO«ny, P| THE GEOLOGY OF THE ENGLISH CHANNEL. 163 level of a sea-bed which consists of fine gravel and fine shelly gravel in patches; while south and east for some distance from the Eddystone are fine sands. South of the Prawle promontory, off the coast-line from Bolt Head to Prawle, is shell gravel, from Prawle to Start, stony ground. The fine sands are quite unlike the silty sand of Plymouth Sound, are coarser as a whole and cleaner. A chart which the writer pre- pared in 1898, from Dr. Allen’s details, is here reproduced; the un- determined areas have not yet been fully worked, and perhaps are better left blank until full information is available. There is a little stony ground at East Rutts, a stony patch off Stoke Point, and stones have been dredged north of the Eddystone, and on the margin of the Hand Deeps. (Plate XIII.) All the stations on this chart are those to which I have elsewhere prefixed the letter A. Station A. 100, south of the Eddystone, gave large stones as well as sand. Stations A.78 and A. 31, although near to and surrounded in part by sand, were actually on rock, and A. 79 yielded Triassic sand- stone. These three points are southward from the Eddystone, on the margin of the fine-sand area. The first matter, the probable date of the stony deposits and their origin, may now be left for a time, to be resumed when the general geological mapping of the area has been attempted. As to the second matter, the extent to which we may rely on the comparatively local origin of the various stones and pebbles, this, too, may be left in part to a later portion of the paper, but enough should be written here to justify the attempted location of the various forma- tions in situ. When a rock is obviously torn from its parent mass, as instanced by its form and freshly-broken surfaces, and when it comes from known rocky, as opposed to stony, ground, the inference as to its im sitw origin is almost irresistible. This is a matter of rare occurrence. Hunt's H. 19 appears to have been a clear instance. The trawler Pelican got fast in what was sup- posed to be a wreck, and remained thus fast for some hours. When the trawl came away, a fragment of granite showing a clean fracture was found in it. This fragment, No. 19, differs from Hunt’s other specimens in that it evidently formed part of a thin slab of rock, and not of a massive block. The stone proved to be a granite of coarse grain, with white and black micas, and a little triclinic felspar in addition to the orthoclase. The locality 20 miles S.W. of Eddy- stone. From practically the same spot, M. 15, the recent dredgings 164 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: raised a fine-grained granite also with both brown and silvery mica. There is evidence that the rock hottom at A. 78, A. 79, is Triassic. While the gneiss from A. 86 (354/1), } mile N.W. of Eddystone, was a large angular slab, with one face of apparently clean fracture. Thus on this class of evidence granite, gneiss, and trias have alike been found in situ. Another feature that argues strongly for a rock being near its first home is the angular or sub-angular form occasionally presented ; especi- ally is this form of evidence of value when the stone is such as will readily suffer from transport. A. 100 (354/2), 2 miles 8.W. of Eddystone, gave large stones, a thin slab of variegated Triassic sandstone, a rather thin slab of buff Triassic sandstone, and a thin piece of red marl, all angular and practically un- worn. Such rocks as these could not travel without great wear. M. 19. 8. 28° W. Edd., 23°3 miles, yielded large square blocks of Red Triassic Sandstone. M. 14. 8. 17° W. Edd., 29°8 miles, yielded thin sharp slabs of Liassic _ limestone. There are other similar instances. Evidence of this type again demonstrates practically in situ exposures of Trias, and in this case of Lias as well. A third clear indication of localisation is when the adjacent sea- bottom yields rocks of the same class and type as shore exposures. The sea-bed off the Bolt and around the Eddystone affords instances. To some extent coupled with this is a fourth strong class of evidence —the restriction of the occurrence of a given type rock to areas with definite boundaries. Thus the Bolt and Prawle schists vary in type as we proceed southward along the sea-bed. The Eddystone and Hand- Deeps gneisses are restricted to the immediate neighbourhood of the reef; in A. 102, S. Edd., 2 miles, the gravel contained no Hddystone reef material, although in A. 87, N.W. by N. Edd. 1 mile, 87% of it is derived from the reef. It will presently be seen how, on a much larger scale, the New Red Sandstone series is definitely bounded. Thus at M. 27, 8. 19° W. Edd., 183 miles, there is a representative series of Triassic rocks; at M. 29, S. 14° W. Edd., 19°8 miles, these are entirely re- placed by the marls of the passage-beds to the Rhaetic. The distance is under two miles. . Another, the fifth, possible proof that a rock is near its point of origin applies in but a few cases. An example will best explain it. On all the preceding arguments we may decide that the gneiss of the Hand Deeps is practically in situ. 354/3b is a red conglomerate of the THE GEOLOGY OF THE ENGLISH CHANNEL. 165 New Red series; it contains derived fragments of the Hand Deeps gneiss and schist; it is found side by side with them, and hence if they are in situ so, too, in all probability, is it. The sixth line of argument for the demonstration of the local origin of the rocks and pebbles is as strong as any. There are some rocks so friable that they might not travel half a mile without being destroyed. Many of the marls of M. 29 above referred to are of this class, the ‘paper shale’ of M. 53a, 8S. 22° W. Edd., 32:2 miles, is another rock which must be content to rest at home or be destroyed. From these which cannot be moved without destruction, through those which can only travel a little way without disintegration, on to others which may journey but must be considerably reduced in their progress and bear evidence of their wanderings, there is a complete succession. The extreme of the class may be taken to be flint, and if entirely unrolled flints are found, as at M. 67, 8S. 19° W. Edd., 405 miles, among other places, it may well be assumed that they are untravelled. On some one or more of these six lines of argument every class of rock found in the dredgings may be shown to be practically in situ at one or more stations. Its associates are arguably almost equally near their points of origin, for it is impossible to attribute to any drift, arising from whatever cause, the selective and confounding ability to bring like to like, to transport from a distance and place among its kin any stone or stones. A little exchange of material between adjacent areas there must be, but we are not about to attempt any geological mapping within extreme narrow limits of error. THE CRYSTALLINE ROCKS. Granites, Diorites, Gneiss, Schist, ete. My. A. kh. Hunt quotes, in a paper above cited, a letter received by him from the late Mr. E. B. Tawney, as follows :— “My views are rather Britannic; I look to Brittany for their origin [the origin of the Channel granites and gneisses, R.H.W.]. I consider Brittany reached to Plymouth Sound and then stopped short, but am inclined to give Start Point to it. If so, the granites are not all pre- Devonian, though pre-Carboniferous.” To much the same conclusion the writer has arrived, as at least a working hypothesis, with the correction that some at least of the Brittany granites are now commonly accepted as of Carboniferous age. To one who has worked in a granite area such as Dartmoor there is nothing unexpected, nothing disappointing in finding, as in the present instance, such considerable variety among the plutonic rocks, 166 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: a variety that by no means in all cases involves difference of origin. For the moment all granites and associated rocks which may have had a Dartmoor origin are excluded from consideration; these are extremely few in number. The first part of this paper must be left to speak as to the variety of the plutonic rocks met in these dredgings. But here such slight evidence of relative age as can be adduced may well be considered. Gneiss is known to occur at the Eddystone im situ ; 1t occurs also at the Hand Deeps and the East Rutts, and not- withstanding the doubt thrown upon the fact, Iam inclined to consider that the ‘Shovel Reef specimen’ was, indeed, obtained near Plymouth Breakwater. This has been rendered the more probable by discoveries made since the time when Mr. A. R. Hunt, on evidence that warranted him in all fairness, challenged the fact. We now know, as we did not then, that gneiss occurs at the East Rutts, and chlorite schist off Stoke Point, in each case without any trace of their presence being visible on shore. Gneiss also occurs at M. 36, M. 9, M. 16, and M. 25 stations, which all lie in a narrow north and south strip, extending from 17°5 miles 5. 37° W. from the Eddystone to 23 miles 8. 24° W. from the Eddy- stone, a strip not quite three miles broad. M. 11x and M. 20g might also be classed as gneiss, and would somewhat broaden the patch referred to. In any event there is a certain localisation about these associated rocks. The writer has always hitherto leant to the hypo- thesis that the Eddystone gneiss was of Archean age. From the features of similarity the gneiss from this area would presumedly be of the same formation. And there is an interesting piece of evidence which at least tends to indicate age. A number of grit stones have been dredged from various parts of the area examined (see p. 142). Among these is M. 9d, and that rock contains as derived fragments particles of just such gneisses as occur in the neighbourhood. It is impossible to correctly date the grits, which may be either Carboniferous or earlier, perhaps more probably the latter. Turning next to the schists. One of the most interesting finds was off Stoke Point, where chlorite schist is not uncommon (see p. 159). This brings the Bolt series many miles west. For the rest, the petro- logical notes give all the useful information. As bearing on the age of some of the plutonic rocks we have to observe that there is an area over which slates are common which show evidence of contact metamorphism. The northernmost point of this area is M. 11, S. 26° W. Edd., 17°8 miles, the southernmost is M. 24, S. 24° W. 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It is to be noted that side by side with these slates occurs a red felsite, and red granites occur also. This distinctly looks like an area where the contact plane of the granite and the sedimentary rock is near to or reaches the surface. Felsites and red-coloured granites would be expected near the junction. If these slates are carboniferous, then the granite is post-carboniferous ; if Devonian, the granite is post-Devonian, in any event not pre- Devonian. Some interesting features attend this area of altered rock. It is true that Hunt’s H.19 granite im sitw occurs 20 miles S.W. of Eddystone. Here, too, have been found the only specimens of schorlaceous granite or aplite M.11c, M.27x; hence come the other true aplites M. 24g, M. 14e, M. 34e; and hence we derive the micro-peg- matite, M. lla, all granitic, and not dioritic rocks. The only schorl rocks, except M.14f and M. 72, come, however, from M. 31 and M. 36, one to two miles north of this area, and possibly in the absence of M. 11c., M. 27x would be regarded as strays. Such was the writev’s first thought ; but considering the nature of the adjacent rocks, he now inclines to believe that both schorl rock and schorlaceous granite truly belong to the area. The presence, in addition to the above-named, of diorite, quartz diorite, and some intermediate igneous rocks is not overlooked. The areas of gneiss and altered slate lie side by side, but neither can claim exclusive occupation of its portion of the bed of the Channel. (Plate XIV.) Since very little good can result, with the present materials, from any further attempt to deal with the plutonic and metamorphic rocks, we next turn to the New Red Sandstone, which overlaps and partially overhes the district just considered. NEW RED SANDSTONE. The westernmost shore exposures of New Red Sandstone are at Thurlestone in Bigbury Bay, and in Cawsand Bay on the Mount Edgeumbe shore. There is also on the beach at Drake’s Island in Plymouth Sound an untravelled block of breccia of Triassic aspect, weighing about four or five tons. The mica-andesite (felsite of the Geological Survey) at Withnoe in Whitsand Bay is an intrusive rock, evidently connected with the red trap in Cawsand Bay, and undoubtedly of New Red age. 354/4b 64 miles W. from Rame Head lies on another exposure of this same igneous series. NEW SERIES.—VOL. VIII. NO. 2. M 168 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : DE LA BECHE, whose work stands as a model of careful discovery and accurate inference, with reference to the red trap of Cawsand writes: “Though unable to adduce direct proof, we are inclined to refer this porphyry, from its general character, to the date of the lower part of the red sandstone series, and to infer that it may be connected with a portion of that series beneath the sea in the direction of Bigbury Bay, on the coast of which, near Thurlestone, we find the patch above noticed.” ? In 1867 PENGELLY, and in 1886 WortH, supplied proof and confirmation as to the age of the ‘porphyry. And in 1898 the writer, as the result of Dr. Allen’s dredgings, was able to assert that there was strong evidence that from the Hand Deeps to Bigbury Bay the New Red rocks were continuous. It may now be added that conglomerates dredged from off the Mewstone Ledge are distinctly of the New Red type. In the gravels and sands between the Eddystone and the Bolt New Red materials everywhere constitute a considerable percentage of the rock fragments. In the vicinity of the Eddystone and the Hand Deeps New Red rocks are found in situ (wherever rock is exposed), through which protrude the reefs. The conglomerate at the Hand Deeps contains fragments of the local schists and gneisses. The lithology of these rocks having been fully treated of in the first part of the paper, it is not proposed to make any repetition here, but pages 144 to 148 inclusive may be referred to. Although the variety of the rocks is considerable, all, or almost all, appear to be Triassic rather than Permian in character. Only one of Hunt's specimens has any bearing on this formation, and that is H. 10, 8. Edd., 20 miles—“ Triassic Sandstone.” Wortu’s discoveries further westward, meeting and overlapping the Association’s latest dredgings, are of especial importance; these carry the Trias to a point W. 5, S.W. by S. (mag ) Dodman, 25 miles, roughly 36 miles from the Eddystone.2 He doubted the eastward extension of the outlier, on evidence which has interest as confirming the Associa- tion’s results. In fact the Trias does so extend, but his two eastern- most points lay one on either side of the broad belt which it forms. His W. 12, S. by E. Dodman, 27 miles, lies about 3 miles north-east from M. 29, and at the latter pomt we now know that the Trias has given place to higher strata. W.12 yielded no Triassic rocks. His W. 6, 8. by W. Dodman, 20 miles, in addition to a salmon-tinted 1 Report on the Geology of Cornwall, Devon, and West Somerset, p. 212, 1839. 2 “On a Submarine Triassic Outlier in the English Channel,” Q.J.G.8., Vol. XLII, 1886, p. 313-15, "AX -238ld dt YNOLSATCUT e tad NYWCWOT “HLYOM HSA QISSHI7T AO*WLIVAHY 1 ‘DLIVHA OL SYIAL*‘STFIF FIVSSY¥S “Ad “SCHOITYA SHLYAOMNA 0D VL *SWIAL ‘1. S Viel SN Ss WV irebek vt rl of TAY Z/7 TILA ‘104 “0088p "Jorg “Lopy “usnor To face p. 168. eile sic: vayndlel ents weet. a i) oe Yay Ah ia nat bony nocthe RoOnsh ae wht ah, uy pre) an oo) gid ap yeep ee tomepetenestn cme mey erie intial pean p sean eran story wy j de Honus, mpl ps 4 byry,’ DP kd f “yt wire it ' int a Stoshs % z * ES on avirlende whi ea hi utero bi in bi the Tea Aloos 0. ent ai Vv ¥ KK 1h buy on) oN) ROR tages saniiletetee /Trinaic), yielded al hel F ot granitio, Le is“ Eeiiarin: be vested, tht fits, thas eon: th. ave maiiles Wate A2e tho ol Pure incariad the fet oor T Beehihow sios¢ oy Pete. hy the gksciabion: ty Which Ooo Ral rodke halve by be) Riwhile Works vorords ane mathed T. (Pky Bae Seve LUG DA aA WC Bhs arg he abies eadial PS ae EAs limestones andi nA . "ee, Fe ‘ aici % Pe. Sree, ae wih Bie KAT te. Fas. wierey te aS Seer ite tare: Lewnanch as Uints ara recorded trom pracitcally avary eiging, i Mvless to place the localities on s.apecial ohelt. . # chart drag, however, bowen wr ide ih Mart: “the can ntioe 2 a bite havd Pee eth. The ueetheuti amian idan would Appear 2! .) ne oad AG 3G, OW Bd. 15 miles: Lis becord qf" 6 amall wiace of peliyacens 1 pagetone, rildted treugh and throygh fy molluscs aud agi waasins csorers,” probably refers te aupioce « of tiug chalk, From ‘thy 2 ine tO BM 41, a distance of, dy, 21 Gautles| records ame frequent fitie Association's dredgings. There is then gay for abou? 14 inal 1d followirte ghis two localities occur, M. 58 and M. 67. (ei oe AVE The affinities of this yellow clisik appear bo be with the PMaibortg Ra Pe. cron Geseribed by Mr. A, J. Tukes-Browub, aod later byBtp a hor uz collaboration with Mx, W. Hills . "Whethor lithological similarity iy this cafe ioplice pa aay be doubtful. Rut the writer is m: dpgipd to My, fy AMD Bere Ne oT 48 Fe bs TiS t tA a hatween those sud his own » Heaton tiitaseky Glee tabher 2a pee Kae Li at thy xe age s indioate a fommeiion bing wii the we du) 0 L . a x aed have Deen Sead if ar ! yeas of Eocene atyate, ovon py das. “s Pe se" (Fare Tees the growads bese spiewas rina ty Mor. = aoa me Oe g hee an sheen froxu his work, The Hee ORL REN Bie aaKE” LOH LAM ‘IA X 2Id WVOLSAUCT @ td NYWTOT HLYOMHA TYSATM/NID ATTY WVLIV AAS *LNI7S “MTVWHD MOTTFIA C4vH *D SHO ADV Laat ‘TILA ‘120A ‘90887 ‘Jorg “ny “usnor To face p. 169. THE GEOLOGY OF THE ENGLISH CHANNEL. 169 calcareous san Istone (Triassic), yielded pebbles of granitic, granitoid, and quartzite rocks, with flints, thus confirming M. 40, five miles westward. On the chart here inserted the letter T indicates those dredgings made by the Association in which New Red rocks have been found; while Wortn’s records are marked T’. (Plate XV.) The point at which the passage-beds above the Trias were found is marked P.B., and L indicates limestones and marls of Liassie type. CRETACEOUS. Inasmuch as flints are recorded from practically every dredging, it is useless to place the localities on a special chart. A chart has, however, been prepared showing the distribution of the hard yellow chalk. The northernmost location would appear to be Hunt’s H. 13, 8.W. Edd.,15 miles; his record of “a small piece of buff- coloured limestone, riddled through and through by molluscs and other marine borers,” probably refers to a piece of this chalk. From this point to M. 41, a distance of, say, 11 miles, records are frequent in the Association’s dredgings. There is then a gap for about 14 miles, and following this two localities occur, M. 58 and M. 67. (Plate XVI.) The affinities of this yellow chalk appear to be with the ‘Melbourn Rock, described by Mr. A. J. Jukes-Browne, and later by the same author in collaboration with Mr, W. Hill. Whether lithological similarity in this case implies identity of age may be doubtful. But the writer is indebted to Mr. Jukes-Browne for the loan of some slides from his collection, and finds much in common between these and his own slides prepared from the dredged material. Unfortunately the latter contains no recognisable remains of any zonal fossils. If of the same age as the Melbourn Rock, the specimens indicate a formation lying at the base of the Middle Chalk. EOCENE. The one block of Eocene limestone is of great interest; it is large, over one foot in length, flat-bedded, and angular. From its nature it cannot have travelled far and preserved its present form; indeed, it must practically have been taken 7 situ. The possibility of Eocene strata occupying some part of the western bed of the English Channel had been recognised before this specimen was taken, and the grounds for that recognition have been so well summarised by Mr. Jukes-Browne, that no apology is needed for in- serting here an extract from his work, The Building of the British Isles (1892) :— “From the superposition of marine limestones upon the lignitic 1 «The Melbourn Rock, etc.,” Q.J.G.S,, Vol. XLII, 1886, p. 216 et seq. 170 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : series of the Paris Basin, and the sudden appearance in them and in their English equivalents of tropical forms of mollusca, it was formerly supposed that a subsidence took place which submerged part of the intervening land and allowed the waters of the great HKocene Mediter- ranean to occupy a portion of the low-lying tract on the northern side of the barrier. But the discovery by M. Vasseur of deposits with fossils of the Caleaire Grossier age near the mouth of the Loire, and the identity of their fauna with that of similar deposits in the httle basin of Carentan in Normandy, makes it much more probable that the Fic. 3. The English Channel in the Middle Kocene Period. . Land areas shaded. (After Jukes-Browne.) incursion of warmer water came from the Atlantic. Professor Hébert remarks that the height of the ground between Carentan and Rennes makes it impossible to suppose that these two basins were directly united. Brittany must have formed a promontory between the inlet of the Loire and a channel which ran through what is now the opening of the English Channel. M. Dollfus is of the same opinion, and has recently proved by his researches along the south side of the Paris Basin that there was a continuous shore-line along that district throughout the whole of the Eocene period. “Tt is fairly certain, therefore, that the opening was westward, and was nothing less than an incursion of the Atlantic into the North THE GEOLOGY OF THE ENGLISH CHANNEL. 171 European region. We may suppose that the Atlantic waves had long been thundering against the western land which united France to Ireland, and that at last only a narrow tract of rocky land between Cornwall and Brittany remained to separate the western ocean from the lowland of the Anglo-Parisian area. The final breaching of this was accomplished during the subsidence to which the Calcaire Grossier testifies; the waters of the Atlantic soon widened the straits, and established a sub-tropical fauna and flora on the southern shores of Britain.” Mr. Jukes-Browne gives a map showing the geography of the Anglo-Gallic area as so interpreted; this with some addition and cur- tailment is here reproduced (Text, fig. 3). The Eocene of Carentan has been marked ‘C, the similar strata near the mouth of the Loire have been marked ‘L,’ and the position of the dredging M.77, from which came the Eocene limestone, is indicated by the letter ‘EK.’ The confir- mation afforded by this discovery to the views of French geologists, in a problem the key to which hes in their country, is a pleasant matter to record. GENERAL CONCLUSIONS. The affinities of the crystalline rocks in the area examined are strongly toward Brittany, and but slightly toward the mainland of Devon and Cornwal.. There is evidence, amounting at the least to a strong suspicion, that the granite which occurs at and around a point 20 miles south 26° west from the Eddystone is post-carboniferous; and this granite exhibits a tendency toward the Dartmoor type. The Triassic outlier off the Lizard and Dodman discovered by the late R. N. Worth has proved to be connected eastward with an even larger area of New Red Sandstone rocks, which may very probably be continuous with the nearest shore exposures. A clear indication of the eastern boundary of the Trias has been found at a point about 20 miles south 17° west of the Eddystone. There seems fair reason to suppose that the western boundary of the Jurassic formations may for a short distance approximate to a line drawn south-west from this point. It may, however, be noted that Lias limestone was found in a detrital deposit at Cattedown (Ply- mouth) by the late R. N. Worth. The Cretaceous rocks dredged from the Channel are now for the first time recognised to include chalk as well as flint. There is some possibility that the rock found is from the base of the Middle Chalk. Flints, in addition to occurring on modern beaches, are found also in the raised beaches of Devon and Cornwall; were very numerous, 172 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : associated with Dartmoor rocks, in the detrital deposits lying on the limestone at Cattedown, and examined by R. N. Worth; have been found by the writer, again associated with Dartmoor rocks, on the floor of clay-filled fissures in the Plymouth Limestone 20 feet below low water, and have been found by him on the rock beds of the Plymouth estuaries, buried beneath the silt. As a result of the dredgings a considerable westerly extension of the boundary lines of the Trias, the Lias, and the Cretaceous must be made on our maps, beyond the present usually accepted speculative bounds. And the theory of an Eocene drift, sometimes put forward to account for the flints, must be abandoned. It appears that from distant geologic time a depression has existed, having the same trend as the western part of the English Channel, and occupying a part at least of the same area. The New Red Sand- stone first distinctly shows the previous existence of this depression. From Torbay to Plymouth the northern verge of the New Red de- posits touches the present shore-line here and there; always the derived fragments in the conglomerates and sandstones are largely from local rocks. From Plymouth to nine miles south-east of the Lizard it runs parallel to the coast without absolutely touching it, and how far further west it extends we do not at present know. An arm of the great inland sea of this period, probably of its later or Triassic years, had its northern shore much where the waters of the Channel now meet the cliffs of Devon and Cornwall. How wide the Trias lake was along this western extension cannot at present be known; its deposits are lost under those of the sueceeding Liassic sea, perhaps to reappear nearer France, perhaps not. During the later Jurassic period this depression would appear to have slowly risen free from the waters, and in part, if not in whole, to have become a subaerial valley. The Cretaceous era witnessed its entire submergence, although the highest points of Devon, where Dartmoor and Exmoor now stand, may have appeared as islands above the surrounding waters. This submergence was gradual. A problematic coast-line of the time of the Lower Chalk has been laid down by Mr. Jukes-Browne.' By that author’s consent the map accompanying his paper in the 7'ransac- tions of the Devonshire Association is here reproduced (Text, fig. 4). It may be that the westerly extension of the Cenomanian sea has not been sufficiently prolonged; be that as it may, the sea of the Upper Chalk sent an arm westward to the Lizard parallel or probably beyond. 1 “Devonshire in the Time of the Lower Chalk,” 7rans. Dev. Assoc., Vol. XXXV, 1903, p. 787 et seq. aS & SISYS SO M ov ANMONE-SaANNe P'V AG LaoW NVI AAsSdae ae AHdWYHDO039 AASNAANS JOALIQNOT 0G Ee oe VYWONSD A1edvdodd o8 Map showing the probable geography of Devon, etc., in the Fic, 4. (By Jukes-Browne. ) Cenomanian Age, 174 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: The next movement of the earth’s surface involved an emergence of the land, and the depression which we are considering came into subaerial conditions once more; how far it had been filled in the meantime by chalk rocks and its features obliterated cannot be decided. We may imagine the denudation and solution of the chalk to have at once commenced, and for a period there existed over the site of the English Channel a valley draining eastward. At this time a profound change in the geography of Northern Europe was imminent; the Western Land was slowly yielding place to the sea, and already Atlantis was almost lost in the ocean. A renewed subsidence brought the eastern sea in constant encroach- ment westward over the site of the Channel and helped bring the Atlantic eastward toward it. In the Middle Eocene period the last barrier to the junction of these waters must have yielded, and for the first time the Atlantic ebbed and flowed in the ancient depression south of the Devon and Cornwall coasts, now re-excavated and largely cleared of the cretaceous deposits. The English Channel may be said to have had its birth. That the sea still occupied the western part of the Channel during the Oligocene, Miocene, and earlier Pliocene periods seems a fair in- ference from all known facts, but no evidence for or against this view is yielded by the dredgings. In later Pliocene times the valley of the Channel was once more dry land, and almost certainly drained west- ward to the Atlantic. There is reason to believe that, during this and the earlier part of the Pleistocene period, features were impressed upon the valley of the Channel which it has never since entirely lost. Despite occasional halts and even retrogressions, the victory has since lain with the sea, which has reoccupied the valley between France and England, and in so doing has modified its contour, bringing into being the Channel bed as it now is. If the true physical history of the Channel has been as above described, does it explain the conditions now found ? The absence of all actual chalk, excepting some peculiarly hard nodules which from their exceptional character offer great comparative resistance to destructive agents, may be attributed to its removal by solution and denudation during periods of subaerial condition. It may have been that some traces were left which were only finally destroyed by marine erosion during the latest incursion of the sea. It may even be that undiscovered patches yet remain. But the flints are left to indicate where the chalk has been. Bare patches of soft sandstone and softer marl present no difficulty of explanation. Assuming the last subsidence to have been even THE GEOLOGY OF THE ENGLISH CHANNEL. 175 moderately rapid, the shore-line would never have presented any con- siderable height of cliff. Fringing the cliff in all bays and many creeks would be beaches of sand and shingle derived chiefly from the local rocks. Beyond the beach, where soft strata existed would be tidal plains of marine erosion, such level surfaces as now exist between tide-marks in Torbay. The constant advance of the sea, the constant depression of the land, would ever carry forward the line of shore, the sea-cliff for the time being existent, and the beach would follow; its material would always be largely derived from the actual cliff, but in part consist of older material driven forward by the waves. The rocky plain would sink beneath the sea, and be left as a rather uniform surface of slight gradient seaward. Little or no beach would be left behind, and the older constituents of the beaches, those derived from the outer previous shore-lines, would never long persist, the constant wear reducing and destroying them. Boulders from harder rocks would not be driven on in the same manner as pebbles and shingle, but would remain near their points of origin. Until, however, some considerable depth of water flowed over them, such boulders would still be liable to wear from ex- ceptional wave action; and, further, we may consider that, especially with the granitoid rocks, submarine weathering must produce, but in a greatly less degree, the familiar effects of subaerial exposure. The chief and important difference would arise from the more uniform temperature of the sea. There is reason to believe that the first mlet of the sea was some- what long and narrow, a comparatively sheltered area, where wave action would be slight. That large and relatively unworn stones might be left here would be no occasion for surprise. And as the land sank and the Channel widened, this first-formed portion of its bed would still receive some shelter, until it was covered with water too deep to permit destructive wave-action. Extending the argument, there seems here a reasonable explanation of the general increase in the size of the dredged stony material outward into the Channel. Other causes may have co-operated. That wave action beyond the forty-fathom line has little or no destructive effect upon the pebbles at present, may be judged by the existence of pieces of yellow chalk and of Lias limestone bored and riddled through and through and yet in pebble form. But in a narrow sea, while the wave action would be slight the tidal currents would be swift, and sand would not readily deposit; hence the fact that these stones were not buried beneath finer deposits derived from the shores. 176 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : Even now, could the fine sands which float about in the Channel find a resting-place in its main water-way, a very short period would suffice to bury the stones and boulders. The surface tow-nets used on the cruises undertaken for the purposes of the International Sea Fisheries Investigations constantly catch considerable quantities of fine sand. But sand which by wave disturbance can be maintained at the surface over a depth of forty or fifty fathoms requires but a slight current to prevent it coming to rest on the bottom. It is not necessarily that the currents scour the inorganic sand from the sea- bed, but that they prevent its settlement there. As regarding organic carbonate of lime, shell, and other material, which is forming even now in the deeper parts of the Channel, the currents must be credited with removing some of this mechanically, some by solution, as the particles become finer by disintegration, and the redeposit of such material must take place in quieter waters. Otherwise from the accumulation of this débris alone the stones would long since have been entirely covered. Defective argument may be based on accurate observation, and if the hypotheses above put forward are found incapable of bearing the test of closer reasoning or of fresh discovery, the apology for their being must stand—that they are based in fact, and in fact the state- ment of which has been in no way influenced by them. On two points further work is in hand: the examination of the flints for fossils, and the closer inspection of the baked shales from the neighbourhood of the presumedly Post-Carboniferous Granite. AN ADDITIONAL NOTE.—THE SANDS AND GRAVELS. Fine materials, sands and gravel, from eighteen dredgings have been examined, but not in such detail as might be desirable. As a whole the mineralogical results confirm the conclusions derived from the stone samples; so closely are these in agreement that a very few points need be noted. M. 29. S. 14° W. Edd., 19°8 miles, gives exactly the same results in the fine material as in the pebbles, small fragments of the passage-bed marls being fairly frequent, and no Triassic rocks present. M. 71. 8.23 W. Edd., 19:0 miles, yields Triassic material, which M. 72, a coarse dredging from the same spot, did not; this is within the New ted Sandstone area. M. 75. S. 20° W. Edd., 38-1 miles, yields a little Trias. M. 65. S. 22° W. Edd., 42:2 miles, possibly contains a little Triassic material. THE GEOLOGY OF THE ENGLISH CHANNEL, Le The southernmost find of New Red Sandstone rocks among the pebbles having been M. 18, S. 29° W. Edd., 23.4 miles, this trace of the same in the sands shows in all probability an outward and downward movement of small quantities of detritus, extending nearly twenty miles, certainly fifteen miles. This is the only evidence of any but very restricted movement among the mineral constituents of the sands, and it must be remembered that Triassic sandstones and marls are present in great quantity on their own area, and the amount of detritus would be proportionately large, some might well have trespassed on to other ground. In all but this matter the inorganic sands agree so precisely with the closely adjacent coarse deposits, even in minute detail, and their constituents are so exactly parallel, that great strength is given to the previously urged view as to the value of the dredgings for approximate geological mapping. In the gravels of some dredgings sharp chips of brown flints are rather common. Such angular flint flakes were taken at M. 37, 8. 41° W. Edd., 17-1 miles, M.71, M 40, M. 73, M. 56, M. 75, M 76, M. 65, and M. 61, 8. 25° W. Edd., 464 miles, extending thus over a long range. For the more part the surfaces of the chips are practically undecomposed, and all are of brown flint. (It is black flint which chiefly shows the extreme alteration referred to in an earlier part of this paper.) These chips do not, however, look quite recent. ‘They are such as would be formed by the mutual impact of subangular flints, possibly but rarely of broken flint pebbles. They could never last long on a beach or in any depth of water to which considerable wave action extended, although such wave action might constantly create a fresh supply. With a stationary shore-line a few such chips might be found a little below low-water mark, but only rarely. On the other hand, with an advancing shore-line and constantly deepening water it is quite easy to imagine that, formed on beaches or in shallow water, they might be placed in deeper water conditions soon enough to preserve many of them from destruction. Taking the deposit at Hallsands as an instance of a flint beach, long stationary, I may say that I have never dredged off that shore any such flint chips, although it must be imagined that some are at times formed. But probably one reason for their absence at Hallsands is the extent to which the shingle has been rounded, and a broken pebble is most rarely found; while with the sea advancing over a land surface covered with unrolled flints the process of rounding these into pebbles or commencing such rounding would give rise to very numerous chips. The fragments are therefore the supplement of the subangular blocks of flint still associated with them, 178 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION : and they persist—firstly, because the original supply was great; secondly, because for some time after their formation the sea was con- stantly deepening over them; and lastly, those only remain which have formed from material capable of resisting decomposition. APPENDIX I. M. Deuesse on the English Channel. Translated extract.! “ Ta Manche, which washes the whole north-west of France, is a shallow sea, its mean depth being no more than 45 metres. Its basin shoals near the coasts of France and England, and also toward the Pas-de-Calais, while deepening toward the Atlantic. “We would direct attention to the submarine terraces which border the coasts as among the principal features of the orography of la Manche. Outside these terraces somewhat numerous banks occur, especially toward the Pas-de- Calais, as, for instance, the Basswre, the Vergoyer, and the Colbart, which lie near and parallel with the French coast. “Note should be made of the central deep which stretches from off the county of Sussex to Finistere. Near cap de la Hague, at the western extreme of Cotentin, it twists and presents irregular ramifications. “Tn breadth but slight, in depth it much exceeds the rest of Ja Manche reaching even, at the west of cap de la Hayue, to over 160 metres. This central deep corresponds to a submarine valley, and that it has not been scoured out by the currents of la Manche its characteristics clearly show. It is formed, on the contrary, by a deep cleavage, having a general direction of E.N.E., and, although very narrow, not yet filled by recent deposits. “Since la Manche is swept by strong currents, it should follow that deposits are not universally received on its bed, which, on the contrary, should frequently be formed of rocks (roches pierreuses) of earlier than the present period; and this, in fact, the soundings show, while these rocks occupy an even greater proportional area of the bed than in other seas. “Tn the first place, they cover large areas in the western part of la Manche ; they border Brittany and Cotentin, which they join to Jersey and the other Channel Islands; and further they unite Brittany to Cornwall, and Cotentin to the south of England. Cutting out on very irregular boundaries, not only do they spread along the coasts, but pass completely across la Manche, extending even to the deepest parts of its basin and the mid-course of its valley. “These rocks are certainly very varied; between Brittany, Cotentin, and Cornwall and Devonshire, they are, however, either granites, or belong to the 1 Lithologie des Mers de France, etc., p.p. 808-9. end AA ee rent a ne eat pr a mo A YOM Se SNE yD aE Sarr roray Why ta ; \ Pen ee ee Nee eNes a rs dy Aa | ded ) found upon water- logged wood, ete. Column perfectly transparent, the mesenteries showing as narrow white lines, the cesophageal region showing as an orange-red patch. The column of this form, tall and pillar-like, as in Gosse’s figure, and the base less lobed. Height about 10 mm. Disk transparent, pinkish-white, white lines as usual; the orange area reduced to thin light red lines around the bases of the tentacles. Mouth orange. Tentacles with indistinct white rings. Reproduction by longitudinal fission would appear to take place in this species. One quite small one was noted, divided into two as far down as the centre of the column. Carlgren remarks in 1896: Studien uber Nordische Actinien, p. 96, Sagartia undata, var. undata B, “ Méglicher- weise ist diese Form identisch mit Gosse’s (nicht Miiller’s) S. coccinea.” Lack of the necessary material and literature prevent an attempt to elucidate the relationship of the form with regard to the above, to S. viduata, to S. herdmani, and to S. (Aetinia) lacerata, and I therefore retain Gosse’s name. 210 NOTES ON SAGARTIIDA AND ZOANTHIDA FROM PLYMOUTH. Sagartia sphyrodeta, Gosse. Specimens were examined from the Asia Shoal, Reny Rocks, and other localities. They all belonged to the var. candida of Gosse. His variety Xanthopis | have not yet met with here, though it occurs on the north Cornish coast. Some of the specimens had a pale bluish or glaucous tinge on the column, and I have seen a variety near St. Ives in which this colour predominated on the column in darker and lighter bands. The tentacles, according to Gosse, number 48 (8+8+16+16). Fischer (1874) gives 8+84+16+32+64. The usual number at Plymouth is 64 (8+8+16+32), but a few have about 100. Their form is changeable. “They are usually spread horizontally, and have their tips bent frequently downwards” (Gosse, p. 73). Sometimes they are much inflated, and curve in all directions, and are often very active. Both these conditions are most frequent in those dredged in the deeper parts of the Sound, and in such also the column is more pellucid and the tentacles more extensile than in the littoral form. I have observed one exhibit extraordinary activity, bending all the tentacle tips, and then straightening them again all together and at the same time. The lines encircling the tentacle bases, usually dark brown, some- times light purple, or only the inner cycles so encircled. They are frequently irregular, spreading out as a dark coloured area, or forming dark patches at the sides of the tenacles. Acontia freely emitted. Transverse sections showed the ectoderm to be well developed (especially in the oral disk), and the mesogloea, though not markedly developed in the body wall, mesenteries, or tentacles, is also thicker in the oral disk, and the sphincter is strong, and shows numerous small cavities. The longitudinal muscle of the mesenteries well developed, the fibres dendritic. Paraphellia expansa, Haddon. This species is not uncommon on the Rame-Eddystone grounds, but I have only been able to examine one living specimen from that area, which had been in captivity for some time. When completely con- tracted, 20 mm. in diameter, and much flattened, the base spread out, sometimes smooth, and at others crenulated, the centre slightly elevated and much wrinkled. The form is very changeable, the flattened base being partly or wholly retracted, the column elevated, and the anemone then assumes the turban shape figured by Haddon, but this is rare. NOTES ON SAGARTIIDA) AND ZOANTHIDAD FROM PLYMOUTH. 211 This specimen does not progress by the usual creeping method, but by drawing in the flat base, inflating one side of the column, and falling over in that direction, thus turning upside down and resting on the partly expanded oral disk and tentacles. One side of the pedal disk is next inflated, and the anemone rights itself again, and so on. The body wall was covered by a thin horn-coloured coating of hardened mucous, in which a good many sand grains were embedded. Remains of an older and thicker coating could be made out. The thin coat was easily removed, and the animal expanded more freely in consequence. The whole base and column were then seen to be “translucent buff’ but with no sign of the “pinkish or flesh colour” on the scapus, as in Haddon’s Irish specimen. Tentacles 6+6+12+4+24+48=96, one cycle more than in Haddon’s examples. They were coloured as given in his plate and description, but varied in intensity, some being largely white, others with a wash of pale chrome, especially about the base. The brown terminal spot very weak or absent. The lateral spots of brown, in two or three pairs, well marked or almost absent. Disk pale brown, with 12 somewhat darker areas radiating from the primary tentacles to the mouth, these areas bordered by double yellowish lines (single in Haddon’s specimens). From the bases of the secondary tentacles, and on a paler ground, lines of white dots run towards the mouth. Mouth raised in a cone, lips pale, throat same, longitudinally ribbed, and banded with dark brown. Acontia freely emitted from the mouth. I recently obtained seven specimens adhering to stones at extreme low water at Zennor, near St. Ives, Cornwall, and as this is a new habitat and locality for this species, a short description may be of interest. An abundant growth of Laminaria and several layers of stones having been removed, these anemones were found adhering firmly to the sides and lower faces of the stones, together with Corynactis viridis and Caryophyllia, ete. When contracted they re- sembled Haddon’s figure (Z’rans. R., Dublin Soc., Vol. iv., Pl. XXXII, Fig. 2), and were invested in a thick brown, wrinkled, bark-like coating, and the scapus proved to be pale flesh colour on its removal. In no case, while in my possession, was a flat or crenulate base to be seen. This is probably limited to specimens living on a sandy bottom. Disk tawny brown. The arrangement of lines and dots was more complicated than in either the Irish or Plymouth specimens, but on the whole was very similar. The tentacles 96 in the larger specimens ; in these also there were slight variations of arrangement of tint and markings. a ys NOTES ON SAGARTIIDA AND ZOANTHIDA: FROM PLYMOUTH, Soon after capture several ejected shells of Homalogyra atornus, which is abundant on the rocks there. P. expansa thus appears to have a fairly wide range on the western coast, and to be variable in colour and form. Epizoanthus couchii, Johnston. Zoanthus couchu, Johnston, 1838; Gosse, 1860. Epizoanthus couchw, Haddon and Shackelton, 1891. A colony dredged on December 6th, 1907, from Duke Rock, Ply- mouth Sound, consisted of fifteen polyps of various sizes attached to a stone. Ccoenenchyme thin and irregular. The larger polyps 15 mm. in length, gradually widening toward the summit. Encrusted with sand. The lower 2 of the column was weak, less encrusted than the summit, and incapable of supporting the upper portion. The upper 3 contractile, and this gives these polyps a “knobbed” appearance. If irritated, the whole column stiffened somewhat, but usually lay bent over, the summit resting on the stone. The half-grown polyps all showed more or less narrowing about the base, but those of 2-4 mm. are the same thickness throughout. Fresh polyps appear to arise as small mound-like swellings in the ccenenchyme. Small isolated individuals were also to be observed on the same stone. Disk concave, olive with white lines. Mouth elevated. Lips opaque white. Tentacles 24 to 28, in two cycles, fairly long and transparent. Tips rather blunt and white. Marginal teeth, 12 to 16. In some cases well developed; in others less so. Lives well in confinement; very timid, contracting at the least vibration. Epizoanthus (?) rubicornis (Holdsworth). Zoanthus rubsicornis, Holdsworth, 1861. Epizoanthus (2) rubicornis, Haddon and Shackleton, 1891. Haddon and Shackleton (1891), p. 653, say: “This species has apparently not been met with since its discovery, and we are unable to do more than recast Holdsworth’s description. We have no doubt that this species is an Epizoanthus.” I have examined two preserved colonies, marked “ Five miles south- west of Rame Head, September, 1902.” Colonies unattached. From their conformation they would appear to have lain free on a sandy bottom, the polyps all being bent slightly upward. NOTES ON SAGARTIIDH AND ZOANTHIDA! FROM PLYMOUTH. Hud bess Colony (a) consists of two large primary polyps growing from a centre, away from one another, and in the same plane; two secondary polyps arising in a similar manner at right angles to the first pair, and two smaller tertiary polyps arising from the bases of the primary pair. Colony (b) is formed upon the same plan, but is more irregular in growth, and consists of seven polyps. Greatest length of colony (a) 40 mm., largest polyp 20 mm. in length, and 5 mm. in width at the summit, and 3 mm. at the base. Breadth of colony 22 mm., the polyps 10 mm. long. Tertiary polyps 5mm. Measurements of (b) very similar. In both colonies there were swellings at the base of the secondary polyps, indicating further branching. Body wall strongly incrusted with sand, a few folds on or below the summit of the larger polyps. Capitular ridges, 15 or 16, not strongly developed. Spaces between the ridges unincrusted. Disk not visible. Tentacles partly retracted, stout, and white, 26 visible in one and 24 in another. Mr. A. J. Smith informs me that they were of an orange-red when fresh. These specimens are evidently identical with that described by Holdsworth, and which was also obtained in the neighbourhood of Plymouth. An anatomical examination was not attempted, as owing to the amount of incrusting sand, and the fact that the specimens had been five years in formalin, the result would be certain failure, to judge by an experience with JL. incrustatus, besides mutilating the colonies. Fresh and less incrusted examples must be awaited and hoped for. In the meanwhile I agree with previous writers as to the close affinity of this form with £. couchii. Parazoanthus dixoni, Haddon and Shackleton. One colony, preserved in alcohol. The label reads: “ Millbay Channel, December Ist, 1902.” This colony, which consisted of over 50 polyps, had evidently been torn off a rock by the dredge, as fragments of stone and Balanus were found still adhering to the coenenchyme. Greatest length of colony 35 mm., breadth 27 mm. Height of largest polyps 10 mm., diameter 4 mm. Ccenenchyme soft, spongy, and abundant. Polyps rather crowded. Body wall slightly wrinkled, owing to the contraction of the polyps. 214 NOTES ON SAGARTIIDA AND ZOANTHIDA’ FROM PLYMOUTH. The whole colony bears a strong resemblance to that figured by Haddon and Shackleton, Revis. Brit. Actiniaw, Pt. II, Pl. LVIII, Fig. 37. Polyps stout, contracting somewhat toward the summit, where they again enlarge. Margin rounded, with 16 to 18 well-developed ridges. Disk and mouth not visible. Tentacles difficult to enumerate, almost all being retracted. Thirty were visible in one large polyp, fairly stout, and dull white in colour. Colony sand colour. A transverse section shows the ectoderm and nematocysts, encircling sinus and canals, endoderm, etc., to be as described by Haddon and Shackleton. The incrustations, consisting of sand grains, spicules, etc., were, however, more numerous than in their specimens. The specimens described by the above-mentioned authors were obtained off the coast of Kerry, Ireland, in 70-80 fathoms. The Millbay pit, from which the present colony was probably obtained, has a depth of from 12 to 17 fathoms. LITERATURE. 1860. Gossz, P. H. Actinologia Britannica. 1861. Hoxpswortn, E. W. H. Proc. Zool. Soc., p. 99. On an Undescribed British Zoanthus. 1874. Fiscuer, P. Recherches sur les actinies des cdtes de France. Arch. Museum de Paris. 1888. Enuis, J. W. Cylista coccinea. Proc. Liverpool Biol. Soc., vol. ii. p. (2 1889. Happon, A. C., and SHackiEetTon, A. C. Rev. of Brit. Actiniaw. Part 1. Trans. Roy. Dublin Soc. 1891. Happon, A. C., and SHackieton, A. C. Rev. of Brit. Actiniz. Part ii. Trans. Roy. Dublin Soe. 1893. CaruerEeN, O. Studien uber Nordische Actinien. Kongl. Svensk. Vet. Akad Handl. Bd. 25. No, 10. 1898. VeErrint, A. E. New American Actinians. Amer. Journ. Sci., ser. 4, vol. vi., p. 493. 1902. Carueren, O. Actinarien der “Olga” Expedition. Wiss. Meeresunter- suchungen. 1902. Parker, G. H. Notes on the dispersal of S. lucia. Contrib. Zool. Lab. Mus. Comp. Anat. Harvard. No. 133. 1903. Davenport, G. C. Variation in the stripes of S. lucia. Mark Anni- versary Volume. Femoral. ) _ Or — Actiniz collected by the s.s. “ Huxley” in the North Sea during the summer of 1907. o) By; Chas, L. Walton, Assistant Naturalist on s.s. Hualey THE following species were obtained :— Bolocera tuedic (Johnston). Bolocera longicornis, Carlgren. Tealia coriacea (Cuvier). Khodactinia crassicornis (O. F. Miiller). Stomphia coccinea (O. F, Miller). Sagartia undata (O, F. Miller). 8S. miniata-(Gosse). S. viduata (O. F. Miiller). S. pallida (Holdsworth). Sagartia sp. Chondractinia digitata (O. F. Miiller). Metridium dianthus (Ells). Epizoanthus incrustatus (Dub. and Kor. ). Cerianthus lloydi, Gosse. ; BOLOCERA TUEDIZ (Johnst.). Voyage XCIII. Station 37. Northumberland ground. 40 fathoms. 1 specimen. Voyage XCIII. Station 56. Lat. 55° 31'N. Long. 0° 53’ W. 55 fathoms. 2 specimens, The specimen from 93-37 was young and damaged. Expanse of disk and tentacles in a contracted condition, 30 mm. Column much contracted and wrinkled, and of a dirty white; outer cycle of tentacles of the same colour, the inner cycles rose-pink. Disk dull uniform pinkish white, mouth the same and protruding, two pink cesophageal grooves. NEW SERIES.—VOL. VIII, NO. 2. P 216 ACTINIA COLLECTED IN THE NORTH SEA Many of the tentacles were missing, especially from the inner cycles; these were three times the length of the outer. The animal, although injured, was still alive when first captured, and the tentacles underwent constant inflation and contraction; during contraction the sulcations showed strongly. The two examples from Station 56 were large, and in size and colour agreed with the description in Gosse’s british Sea Anemones and Corals, p. 186-7. Gosse there writes that the column is “studded somewhat sparsely with minute rounded warts, scarcely apparent when the animal is extended,” etc., and also quotes Cocks to this effect ; Carlgren, in 1891, discusses the matter, and concludes that the warts described were due to the contraction of the body wall. In the two examples now under consideration, no warts were to be found when living and expanded, but when preserved and contracted the body wall is thrown into innumerable wart-like folds, which any one who had not seen the animal in a living state might easily take to be genuine warts. The figure on Plate V (of Gosse) certainly does not show a fully expanded specimen, as the tentacles are contracted (for although incapable of retraction they can be considerably contracted). The number of tentacles present in the more perfect specimen amounted to 127, but so many had been thrown off that anything like an accurate enumeration was impossible. The internal preservation was bad, but 77 pairs of mesenteries were recognisable. Measurements fo a preserved specimen:—Breadth of pedal disk, 40 mm. Breadth of oral disk, 50 mm. Height of column, 55 mm. Length of tentacles of the inner cycle, 40 mm., of outer cycle, 15- 20 mm. In colour, one approximated very nearly with Gosse’s description, but paler; the other very pale, merely tinged with pink and light brown on the inner face of the tentacles, etc. The stomach protruded considerably. BOLOCERA LONGICORNIS, Carlgren. Voyage XC. Station 7. Great Fisher Bank. Lat. 56°59’ N. Long. 2° 53° E. 38 fathoms. 2 specimens. Voyage XC. Station 10. The Gut. Lat. 56° 40’ N. Long. 1° 32’ E. 50 fathoms. Abundant, and at other stations in this area. — Voyage XCIII. Station 99. Lat. 55° 48’ N. Long. 0° 49’ E. 45 fathoms. 1 specimen. Voyage XCIII. Station 101. Lat. 55°48’ N. Long. 1° 4’ EK. 40 fathoms, 1 specimen, DURING THE SUMMER OF 1907. Pel Voyage XCIII. Station 106. Lat. 55°41’ N. Long, 2° 13’ E. 43 fathoms. 7 specimens. Voyage XCVI. Station 1. Lat. 56° 0° N. Long. 3° 23’ E. 38 fathoms. 4 specimens, Voyage XCVI. Station 5. Very near last. 274 fathoms. 1 specimen. This species was first described by Carlgren, in 1891, from specimens obtained on the west coast of Sweden, from depths of from 40-80 fathoms. In 1893 he gave a much more detailed account, and mentions the Gullmars-fjord, “ other localities on the Swedish west coast,” and the Skagerrak as its distribution. Only a few of those obtained by the s.s. Hualey were in a perfect condition, the best being those taken in the Agassiz trawl during short hauls ; those from beam hauls of several hours’ duration.being frequently almost destitute of tentacles, which would be found adhering to the mesh in all parts of the trawl. None of the specimens attained the dimensions of those described by Carlgren, and measurements of fully expanded specimens were not easy owing to the generally great and usually unequal inflation of the body wall. The height of the column varying from 50 to 100 mm. Breadth of oral disk usually equal to the height. Length of inner _ eycle tentacles up to 80 mm, the outer 25-30 mm. Pedal disk thin and not well demarcated. None were attached, but were free in the trawl, and only adhered in a slight degree to any vessel in which they were kept, and as they showed no sign of having been torn from any object it is probable that they le loosely upon the bottom (sandy). Column smooth and polished and thin, finely wrinkled when con- tracted. Tentacles 160, in six cycles in the larger specimens, stout, tapering to the tip, strongly sulcated, fairly contractile, constricted at the base, and very readily thrown off. Disk smooth, two large cesophageal grooves, stomach freely protruded and grooved. ‘Some few were of the colours described by Carlgren, “ flesh colour all over, tentacles often brown-red on the inner side, gonidial-tubercles and primary mesenteries weak carmine.” But the majority had the column chestnut or dull orange (the mesenteries showing as faint white lines during distention) Tentacles maroon or, rarely, chestnut, the inner faces much darker than the outer, and the inner cycles darker than the outer. Disk a warm flesh tint, or light orange-brown, with numerous irregular radial lines of dark brown or maroon, of varying widths, but widest and darkest about the base of the tentacles. Cisophageal grooves flesh colour. Throat and stomach brownish pink. The colours persist well 218 ACTINIA COLLECTED IN THE NORTH SEA in preserved specimens. 2. longicornis is not easy to keep alive, and soon after capture usually protrudes the stomach walls to an enormous extent, collapses to an abject flatness and dies. RHODACTINIA CRASSICORNIS (0. F. Miiller). In 1902, O. Carlgren, in his paper on the Actinic of the Olga expedi- tion considered that the name Urticina (Tealia) crassicornis really covered three species belonging to two genera, Le., Rhodactinia crassi- cornis (O. F. Mill), Zealia cortacea (Cuv.), and Tealia lofotensis (Dann.). Unfortunately I did not see this paper until after the voyages, and regarded all the forms obtained as varieties of Urticina crassicornes. merely making notes on colour and external characters at the time of capture. In these notes I however distinguished three forms: (a) U, crassicornis, the normal form of the littoral area ; (0) the large deep-water form, the Vealia tuberculata of Cocks and Cunningham, and (c) a form with small warts, occurring on the Great Fisher Bank. A subsequent anatomical examination of such specimens as were preserved shows this last to be &. crassicornis and the other two to be forms of 7. coriacea. It is thus almost impossible to assign all the numerous records to their real species, only those cases where my notes actually notice the size of the warts and the preserved specimens can be safely noticed. R. crassicornis occurred at several stations during Voyage XC about the region of the Great Fisher Bank, together with B. longicornis and Chondractinia digitata. Almost all the specimens were large, having an expanse of from 12 to 14 em. They were attached to valves of Cyprina islandica and Modiola, both dead and living, and /usus antiquus, either living, empty, or tenanted by Hupagurus bernhardus, and once upon the shell of a living #. turtones. The small warts which beset the upper part of the column are arranged in irregular vertical rows, and during partial contraction the arrangement frequently appears annular. The colouration is very variable; the following were noted :— (a) Much resembles Gosse’s description and plate of bolocera eques. The margin was frequently not retracted, even when the tentacles had been withdrawn. The disk, however, was never “pellucid,” nor was the scarlet tentacular ring bounded by white, as described by Gosse. When I first saw this I took it to be B. eques. (6) Column dull orange, the summit white. Tentacles dull pink, the scarlet ring indistinct. Disk pale orange. DURING THE SUMMER OF 1907. 219 (c) Like the last, but the disk dull pink, and the mouth area vivid rose-red. (d) Column as (a). Disk dull white, smudged with yellow. Ten- tacles a fine rose-red, inner faces darkest, scarlet ring not distinguishable, basal lines chestnut. (ec) Column as (a). Disk red. Tentacles with an indistinct white ring, no scarlet band. (7) Column dull orange, summit red, the fosse blue. Disk cobalt blue, two red circles around the mouth. Tentacles dull orange-brown, red ring well defined, basal lines faint. In others the column was blotched with scarlet. In all cases the warts were white. The stomach frequently everted to a considerable extent. The food of this species appeared to be varied, a full-sized Spatangus purpureus and larger shells of Cardiwm and Psammobia were ejected after capture, and considerable masses of 7'ubularia, though this may have been obtained in the trawl. Those kept alive swallowed Dendro- notus arborescens with avidity, but refused Z'iritonia hombergi. TEALIA CORIACEA (Cuvier). The large deep-water form, described as Actinia tuberculata by Cocks and Yealia tuberculata by Cunningham, was obtained from various localities. The colours are generally pale and the warts on the column large. The tentacles 160 in number; in several there was a bifurcation of one or more. Usually attached to shells (dead). Near the coast, in shallow water, specimens resembling the ordinary shore form were obtained. STOMPHIA COCCINEA (0. F. Miiller). Actinia coccinea, Miiller, 1776. Stomphia churchie, Gosse, 1859, Stomphia coccinea, Carlgren, 1893 and 1902. Voyage XCIII. Station 47. Off Seaham. 14 fathoms. 1 specimen. Voyage XCIII. Station 65. Lat. 55° 35’N. Long. 0°50’ W. 45 fathoms. 6 specimens. Voyage XCIII. Station 73. Lat. 55° 39’N. Long. 1° 10’ W. 50 fathoms. 7 specimens. . Voyage XCIII. Station 75. Near the last. 50 fathoms. 11 specimens. 220 ACTINLA COLLECTED IN THE NORTH. SEA Voyage XCIIT. Station 77. Off Holy Island. 32 fathoms. Common. Voyage XCIII. Station 82. Off St. Abbs. 37 fathoms. 1 specimen. Voyage XCIII. Station 83. Lat. 56° 7° N. Long. 1° 22’ W. 42 fathoms. 1 specimen, and at a number of other stations in that area a few specimens, or common. Voyage XCIV. Station 23. Lat. 53° 49’ N. Long. 0° 15’ E. 15 fathoms. 1 specimen. Voyage XCVI. Station 20. Lat. 54° 11'N. Long. 1° 40’ E. 22 fathoms. 1 specimen. Adhering to stones and dead shells. Several from 93-77 were upon living shells of Aporrhais pes-pelecani, the dead shells used were usually Modiola modiolus and Psammobia ferrensis, etc. In confinement this species displays much restlessness, detach themselves and roll about the vessel or tank, re-attach and again loosen, and so on, also as Gosse observes (p. 222), “ very protean in shape,” and frequently assumes the shape shown in Gosse’s figure (Pl. VIII). Colours very variable; the column is always smooth, and has a satiny lustre, the crimson or yellowish white predominating according to the individual. Disk dull red or white, streaked with red; lips usually crimson ; throat dull white or pink. In some specimens acircle of dull spots upon the inner third of the disk. (M&sophageal grooves, two, red. The pedal disk is frequently flecked and streaked with red of con- siderable intensity ; this is probably corellated with the habit of living for varying periods unattached, lying on the side on hard rocky ground such as it favours. The tentacles pellucid white, with one or two bright red rings, or only one ring near the tip; sometimes the rings are in- distinct or a white ring below the red ones. Red lines frequently run down the sides of the tentacles on to the disk. In some also a white spot is present at the base of each tentacle of the two inner cycles, thus forming two alternate circles of white spots. In several, from XCIIT. 90, the column and disk were very pale and almost transparent, but the tentacles and throat were red. It was noticeable that when a series of stations was worked at intervals away from the coast (Northumberland), the colours of this spezies became more and more faint, until the column was so trans- parent that the mesenteries could be counted with ease. SAGARTIA UNDATA (0. F. Miller). _ Actinia undata, Miller, 1788. Zool. Danica. Sagartia troglodytes, Gosse, P. H., 1860. Cylista undata, Andres, 1885. Sagartia undata, Carlgren, O., 1893. DURING THE SUMMER OF 1907. 221 Voyage XCV. Station 24. §. edge of Coal Pit. 13 fathoms. 1 specimen. _ A small specimen attached to a stone among Serpule and Balanus, and only visible when elongated and expanded. Column cylindrical pink, white longitudinal lines near the base, some sand attached. Disk pure satiny white. Mouth flat, throat buff. Tentacles 70-80, not very long, yellowish white, barred transversely, some with two ill-defined dark lines upon the front face, and a rather prominent B mark at the foot. SAGARTIA VIDUATA (0. F. Miiller). Voyage LXXXIX. Station 22. Lat. 54° 28’. Long. 2° 363’ E. 18 fathoms. 1 specimen. Voyage XC. Station 2. Off Esbjerg. Lat. 55° 225’ N. Long. 8° 103’ E. 8 fathoms. Several specimens. Voyage XCII. Station 10. Lat. 54° 0’ N. Long. 6° 462’ E. 16 fathoms. 6 or 7 specimens. Voyage XCII. Station 28. Lat. 54° 513’. Long. 6° 38’ E. 22 fathoms. Common. Voyage XCII. Station 31. Lat. 54° 4727’. Long. 6° 30’ E. 21 fathoms. Abundant. Voyage XCII. Station. 34. Lat. 54° 2’. Long. 6° 54’ E. 14 fathoms. Several. Voyage XCII. Station 42. Lat 54° 23’. Lor Fairly common. Voyage XCIV. Station 54. Sole Pit. 47 fathoms. 2 specimens. Voyage XCIV. Station 56. Sole Pit. 45 fathoms. Voyage XCVI. Station 15. Lat. 54° 30’ N. Long. 3° 59’ E. 25 fathoms. Fairly common. Voyage XCV1. Station 17. Lat. 54° 20’ N. Long. 1° 43’ E. 24 fathoms. 1 specimen. Upon stones, valves of Ostrea, lumps of slag and one from 89-22 in a hollow on a lump of “Moorlog,” also inside empty shells of Buccinum. Colours, etc., as described by Gosse, Carlgren and others, those from more than 40 fathoms paler than usual. ie Le Be ol?) datboms: (ey 1g. SAGARTIA MINIATA (Gosse)._ Voyage XCII. Station 28. Lat. 54° 5132’. Long. 6° 38’ KE. 22 fathoms. 8-9 specimens. Voyage XCIII. Station 27. Off Whitby. 25 fathoms. Voyage XCIV. Station 54. The Sole Pit. 47 fathoms. 5 specimens, and at four other stations in the same area, common. 222 ACTINIA COLLECTED IN THE NORTH SEA Voyage XCV. Station 7 Smith’s Knoll, L. V. 26 fathoms. 5 specimens. Voyage XCV. Station 20. Knoll Deep. 22 fathoms. 4 specimens. Voyage XCV. Station 24. 8. edge of the Coal Pit. 13 fathoms. Fairly common. Voyage XCVI. Stations 15 and 16. Tat. 54° 30’ N. Long. 3° 59’ E. 25 fathoms. Very common. Voyage XCVI. Station 17. Lat. 54° 20’ N. Long. 1° 43’ E. 24 fathoms. Fairly common. Voyage XCVI. Station 18. Lat. 54° 20’ N., near Long. 1° 43’ E, 24 fathoms. One or two. This species usually occurs in colonies upon living and dead Ostrea, frequently clustered about the base of a colony of Aleyoniwm digitatum (growing on the Ostrea also), their bases overlapping or overlapped by the edge of the colony of A. digitatwm, and often with 8. viduata. The colour as a rule is very variable, particularly as regards the outer cycles of tentacles, the “core” of these, though generally scarlet, may be orange-red, faint orange, or without any difference in colour from the inner cycles. Disk also variable, each colony usually being fairly uniform as to the colour of the outer tentacles and the number of the “gonidial” radii, one colony of 7 (from 96-15) having one very broad white radius each, and the same occurred in a colony of S. viduata from the same station. Those procured in the Coal Pit in from 42 to 47 fathoms, bottom black mud, were identical in colouring (and as bright in colour) as those abundant in rock pool at low tide at Kast Hartlepool. SARGARTIA PALLIDA, var. RUFA (Holdsworth). Voyage XCVI. Station 15. Lat. 54° 30’ N. Long. 3° 59’ E. . 25 fathoms. 8 or 9 specimens. | This colony was attached to a valve of Ostrea, together with young Metridium dianthus, to which, when contracted, they bore a strong superficial resemblance, and where that species is abundant would be easily passed over as the young form of one of the colour varieties. Size of largest specimens.—Expanded diameter, 20 mm. Height, 15mm. Length of tentacles of inner cycles, 10mm. Column smooth and of a uniform dull orange-brown. Base somewhat spreading. Disk dusky white, mouth and throat orange ribbed. Tentacles numer- ous, about 200 in 5 (?) cycles, a double white spot at the base, which is also encircled by bowed bluish black lines; these lines give the disk a dusky appearance, and show through the body wall when contracted as a broad blackish band. One very young specimen had the column orange in colour and only eight tentacles; another, somewhat larger, DURING THE SUMMER OF 1907. 223 24 tentacles. In the first of these the basal lines were not visible; in the one with 24 tentacles they were blue, and the tentacles had a faint white core. Acontia were emitted from both mouth and column. These larger specimens were much more robust and darker in colour than any I have seen on the English or Welsh coasts; in such the column is generally white or pale orange (as in the young form described above), and the basal lines blue or purple. With the exception of this species (and the next to be described) the anatomy of most of the forms obtained by the Huxley is well known. An attempted investigation of this species ended in failure; the tissues were hard and brittle, due to preservation in too high a per- centage of formalin. The external form and colour were excellently preserved however. It would be well when several specimens are obtained to preserve those intended for anatomical purposes in alcohol, and museum specimens in formalin. SAGARTIA SP. Voyage XCIV. Station 56. The Sole Pit. Lat. 53° 36’ N. Long. 1° 30’ E. 45 fathoms. 1 specimen. Attached to a dead valve of Ostrea. Expanded diameter, 25 mm. base slightly exceeding the column, outline irregular and lobed. Column firm, much wrinkled during contraction, slightly so when expanded. The summit smooth, margin tentaculate; a few weak suckers on the upper parts of the column. Colour of column dull white, the mesen- teries showing as white longitudinal lines, especially about the base. Disk transparent white, the mesenteries showing as numerous white radial lines; mouth large and frequently gaping; lips lobed, yellowish ; throat brownish buff. Tentacles about 96 in number, thick and swollen at the base, tapering gradually to the tip, white (showing an irregular white core during con- traction), with a faint lilac tinge, stronger upon the lower parts and most pronounced during contraction. During complete contraction the tentacles show through the column wall as a broad lilac or light purple area. Examination with a lens showed this colour to occur upon the tentacle in little streaks. Acontia sparingly emitted and only after severe irritation. Much flattened upon complete contraction. I am not aware of any species of the genus to which I can safely refer this form, but it appears to be nearly allied to S. miniata; further material may provide additional evidence and permit of the form being examined anatomically. 224 ACTINIA COLLECTED IN THE NORTH SEA CHONDRACTINIA DIGITATA (0. F. Miiller). Occurred frequently in abundance at many stations in the region of the Great Fisher Bank and about Lat. 55° 31’ N., Long. 0° 53’ W.; 55° 48’ N., 0° 49’ E.; 55° 44’ N., 1° 40’ E., and many other stations in those areas in from 34 to 55 fathoms. Generally attached to the shells of various species of Fwsus, either living or inhabited by EHupagurus bernhardus. Those from the Great Fisher Bank showed great variability in the size of the warts and colour of the column, ete.; there might be but one row of prominent warts near the summit, or they might be scattered thickly over the greater part of the column, and the colour of the column varied from dirty white to dull orange, and the tentacles from dull pale lilac to ight brown. In a few there was a tendency to mammillation in the warts thus approaching C. nodosa, though none could be placed in that species. Carlgren mentions similar cases, but in a region where both forms were to be found. He found it difficult to determine to which species some individuals should be assigned. METRIDIUM DIANTHUS (Ellis). This species was found so constantly and abundantly throughout the entire area investigated, as to render an enumeration of localities un- necessary. All the colour varieties mentioned by Gosse, Carlgren, and others were represented, with the exception of the sulphur and lemon- yellow; this appears to be somewhat rare (it is abundant in places on the coast of N. Wales). The most frequent in the North Sea isa dirty white, especially in the deeper water. Carlgren (1893, p. 102) says “Die rein weisse Varietat ” (var. sidonea, Gosse, 1860, p. 13) “ habe ich nur in tiefem Wasser angetroffen.” In shallower areas the red, pink, and pale orange are abundant; the dark brown and olive forms were only taken occasionally. This species is to be found attached to stones, wood, Alga, Aleyonidium gelatinosum, Buccinum, Fusus (in such it usually occupies the apical region), upon the surface of Cancer pagurus, ete.,etc. I have seen a large female Cancer almost entirely covered by an enormous red anemone. Pycnogonum littorale is frequently to be found clinging about the base of this species, and on several occasions I have observed it feeding upon this and other species. The proboscis is sunk deeply into the tissues, and the claws are hooked into the body wall. It requires a sharp pull to draw out the proboscis, and the tissues around the puncture were generally discoloured, showing the proboscis to have DURING THE SUMMER OF 1907. 225 remained inserted for some considerable time. P. littorale was ob- served feeding in a similar manner upon Chondractinia digitata in the region of the Great Fisher Bank, and Sagartia miniata from the Sole Pit, neither the tough body wall in one case nor the acontia in the other being sufficient protection. The coloured tissues of the anemone were often visible within the body and proboscis of the Pycnogonum, and that these attacks may prove fatal to young Actinians was observed in my aquaria in the spring of 1907 at Newquay, in Cornwall, a young Sagartia being speedily killed, and young Bunodaetis thallia (Gosse) were much injured. I have since seen it feeding upon Actinia equine, Linn., and young M. dianthus in the Plymouth aquaria. EPIZOANTHUS INCRUSTATUS (Diib. and Kor.). Voyage XCIII. Station 34. East of Shields. 38 fathoms. Common. Voyage XCIII. Station 37. Northumberland ground. 40 fathoms. 5 specimens. Voyage XCIII. Station 59. Lat. 55° 31’ N., 0° 36’ W. 47 fathoms. Common, and a number of other stations in that areain 40 to 57 fathoms. The colonies varied greatly in size, number of polyps, ete. All were incrusting forms, forming carcinecia by replacement of the shells of gastropod shells; the carcinecia were inhabited by various species of Eupagurus. The smallest colony consisted of 4 polyps. The largest obtainec measured 42 mm. in length, and the polyps varied from 12 mm. in height and 7 mm. in breadth to 6 mm. by 4 mm. The number of polyps in a colony was usually 10, but as many as 30 were counted in one case, many of these being, of course, mere buds. The incrustations were extremely dense, the ectoderm and mesogloea being permeated with sand, and there was usually a considerable amount in the celenteron. Repeated attempts to observe the polyps expanded all failed, owing to the motion of the ship, the animals being very timid. CERIANTHUS LLOYDII, Gosse. Voyage XCIII. Station 36. East of Shields. 38 fathoms. 2 specimens. Voyage XCIII. Station 39. Northumberland ground. 34 fathoms. 1 specimen. Voyage XCIII. Station 70. Lat. 55° 39’ N. Long. 1° 10’ W. 50 fathoms. 1 specimen. Of these only the last was in a sufficiently good condition to be.of use, the others were badly injured by the trawl. 226 ACTINIA COLLECTED IN THE NORTH SEA. Length when living, 60 mm. In spirit, 27 mm. Column cylindrical, tapering gradually posteriorly. Body wall transversely wrinkled, the upper portion also grooved and ridged longitudinally, each ridge corresponding to one of the fully developed tentacles of the marginal cycle. Tentacles of the marginal cycle about fifty in number, but difficult to determine, as many were quite small and evidently just developing. It was likewise impossible to enumerate the inner tentacles in a preserved condition as they were crowded together and broke in pieces if any attempt was made to separate them. The animal would not expand fully when alive. When living the colouration agreed with the description given by Gosse. The column was uniform yellowish white, with a dark olive- green band at the summit, they area from which they arise white, and upon the base of the tentacles a series of maroon or purple patches. Marginal tentacles slender, not long; light yellowish brown, with in- distinct bars of chestnut brown across the inner faces. The oral series very dark maroon. LITERATURE. 1860. Gossg, P. H. Actinologia Britannica. 1889. Happon, A. C. Revision of British Actiniz, Part I. Proc. R. Dublin Soe. 1889. CunnincHamM, J.T. Tealia tuberculata. Journ. Mar. Biol. Assoc. 1890. Dixon, G. Y. and A. F. Note on T. tuberculata, etc. Ann. and Mag., Nat Hist., Vol. V. 1891. CARLGREN, O. Das genus Bolocera, Ofr. Kongl. Svensk. Vet. Akad. 1891. Happon, A. C., and SHackyrEron, A. M., Rev. Brit. Actiniz, Part II. Proc. R. Dublin Soe. 1893. CARLGREN, O. Studien uber Nordische Actinien. Svenska. Ak. Handl. 1902. % » Olga Actiniaria. Meeresuntersuchungen. Heft I. 1905. Rove, L. Cerianthes d’atlantique nord. ieee Nudibranchiata Collected in the North Sea by the s.s. “Huxley” during July and August, 1907. By C. L. Walton, Assistant Naturalist on the s.s. Hualey. Durinc July and August, 1907 (Voyages XCII, XCIII, XCIV, XCV, and XCVI), the s.s. Huxley worked a series of stations reaching from near Cromer to St. Abb’s Head more or less parallel with the coast line, and also a series further to the north, and extending around the eastern borders of the Dogger Bank. Many of the hauls were in and about “roughs,” and, as might be expected, a considerable number of species of Nudibranchs were obtained, some of them of considerable interest. The specimens were examined in the living state as thoroughly as circumstances permitted, and as often as possible in their natural environment. Unfortunately in many cases this was impossible, as the animals had become either detached in the dredge or trawl, or were found adhering to the mesh of the nets, and were in consequence more or less injured. All the specimens were killed with menthol, preserved in formalin, and subsequently re-examined in the Laboratory at Lowestoft. The following species were obtained :— Aecolidiide. . Aeolidia papillosa (Linn.). . Aeolidiella alderi (Cocks). . Aeolidiella glauca (A. & H.). . Cuthona nana (A. & H.). . Amphorina aurantiaca (A. & H.). . Cratena amena (A. & H.). . Galvina cingulata (A. & H.). . Galvina picta (A. & HL). . Galvina tricolor (Forbes). CO be Oo OT om Ol 228 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA 10. Coryphella gracilis (A. & H.) 11. C. lineata (Loven). 12. C rufibranchialis (Johnst.). 13. C. salmonacea (Couth.). 14. Facelina drummondi (Thomp.). Lomanotide. 15. Lomanotus gener (Verany). Dotonide. 16. Doto coronata (Gmelin). 17. D. fragilis (Forbes). Dendronotide. 18. Dendronotus arborescens (Miller). Tritoniide. 19. Tritonia hombergr, Cuvier. 20. 7. plebera, Johnston. Doridide. 21. Archidoris testudinaria (A. & H.). 22. A. tuberculata (Cuvier). Polyceride. 23. Acanthodoris pilosa (Miller). 24. A. subquadrata (A. & H.). 25. Lamellidoris bilamellata (Linn.). 26. Goniodoris castanea, A. & H. 27. Idaliella aspersa (A. & H.). 28. Ancula cristata (Alder). While following Bergh, Vayssiére, Trinchese, and other authors in regarding Coryphella rujibranchialis, C. pellucida and C. landsburgii as synonyms, I have preferred to treat C. gracilis as a good species, and also describe Coryphella salmonacea as occurring in the British area. #ZOLIDIA PAPILLOSA (Linn.). Voyage XCVI. Station. 15. Lat. 54° 30’ N. Long. 3° 59’ E. 25 fathoms. 1 specimen. Length 2 cm. The colouration almost identical with that of most littoral specimens. The triangular white mark on the head prominent. Oral tentacles of a clear white, spotted with opaque white. Body, DURING JULY AND AUGUST, 1907. 229 rhinophores and papille, dull yellowish white, freckled with brown. Tail very obtuse. The specimen was found upon a colony of Aleyoniwm digitatum. AZ0LIDIELLA ALDERI (Cocks). Voyage XCVI. Station 15. Lat. 54° 30’ N. Long. 3° 59’ E. 25 fathoms. 1 specimen. Found on Alcyoniwm digitatum. Length about 16 mm. When first obtained the specimen was taken to be a variety of A, glauca, but upon examining it in the Laboratory I found that it belonged to the present species. Oral tentacles longer than the rhinophores, and white; rhinophores stout, wrinkled, bright orange-red, and very like those of A. glauca. Papille set in 8 or 9 rows, of a reddish chestnut colour, paler at the bases and tips, and more or less freckled with white. The “ruff” was not well marked, but the papille forming it were paler than the rest. All the papille were erected upon irritation. Tail tapering to a fairly fine point. The radula agreed generally with Alder & Hancock’s plate and description. There were 14 plates of a clear yellowish white, tapering gradually ; the central tooth rather stronger than in their figure, and the laterals 24 in number. AZ0LIDIELLA GLAUCA (A. & H.). Voyage XCV. Station 24. 8S. edge of the Coal Pit. 13 fathoms. 1 specimen, Voyage XCVI. Station 18. Lat. 54° 16’ N. Long. 1° 46’ E. 23 fathoms. 2 specimens. The specimen from XCV—24 was upon Aleyonium digitatum. Those from XCVI—18 were found clinging to the meshes of the beam trawl, but 4. digitatwm occurred commonly in the haul. All the individuals agreed with Alder and Hancock’s specimen in form, but showed considerable variation in their colouration, especially in the colouration of the papille. (a) In the specimen from XCV—24 the length was 14 mm. The rhinophores were somewhat wrinkled, short, stout, and tipped with white. Oral tentacles semi-transparent and freckled all over with white. Body and papille as in Alder and Hancock’s plate. Eyes plainly visible. (b) Those from XCVI—18 measured 35 and 25 mm. in length, respectively. 230 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA In both the papille were for almost their whole length of a dull green, freckled with opaque white, no red being seen. In (a) the head and body were as figured by Alder & Hancock; in (d) the oral tentacles were much paler, and the head and rhinophores of a dull uniform red. The animals showed little activity, but both crawled on the surface film on several occasions. EK. Hecht (Contribution a Pétude des Nudibranches, 1896) says of this species: “Remarquable par la variabilité de sa coloration, qui est parfois plus foncée que celle indiquée par Alder et Hancock, et plus souvent d’un jaune grisatre.” CUTHONA NANA, A. & H. Voyage XCII. Station 45. Edge of Sylt Outer Rough. 13 fathoms. Several specimens. Voyage XCII. Station 46. Edge of Sylt Outer Rough. 13 fathoms. Several specimens. ‘ Voyage XCIII. Station 9. N. of Dogger Rough. 13 fathoms. Several specimens. Voyage XCIII. Station 19. Bruecy’s Garden. 27 fathoms. 6 specimens. Most of the specimens obtained were small, four of those from XCIII—19 measuring 9, 8, 6 and 4 mm. : All were feeding upon Hydractinia echinata. Those from XCII—45 were upon a large specimen of Hyas coarctatus, which was almost covered with a growth of Hydractinta. Some nine individuals, mostly small, were clustered upon the under side of the head of the crab, and several others upon the crapace. All were of a transparent white, the papille having a hight chestnut or pink core. Those obtained at the other stations were upon Hydractinia, encrust- ing the shells of Natica monilifera and Buccinum. Leslie and Herd- man (Zhe Invertebrate Fauna of the Firth of Forth, 1881) also record C. nana on Hydractinia at “Morrison’s Haven,” collected by Dr. T. Strethill Wright. AMPHORINA AURANTIACA (A. & H.). Voyage XCIV. Station 47. Outer Dowsing Ground. Lat. 53° 283’ N. Long. 1° 93’ E. 144 fathoms. 1 specimen. Length 1 cm. The specimen differed slightly from Alder and Hancock's plate and description, the rhinophores being wrinkled and slightly shorter than the oral tentacles. The white area below the tips of the papillae very faint; the animal was damaged, and many of the papille were missing from the posterior region. DURING JULY AND AUGUST, 1907. Fort It was living upon a colony of Tubularia larnyx, which was growing upon a large stone. The spawn, which was similar to the figure of Alder and Hancock, was attached to the bases of the 7ubularia. CRATENA AMOENA (A. & H.). Voyage XCV. Station 23. S. edge of the Coal Pit. 24 fathoms. 2 specimens. The two examples of this most beautiful species were discovered creeping about the base of a colony of Sertwlaria argenta, growing upon a dead valve of Pecten opercularis. Length 6 and 4 mm. respectively. They differed from Alder and Hancock’s plate and description in the following particulars, but otherwise were similar :— 1. The oral tentacles were not much longer than the rhinophores, and were white and without the brown band. 2. There was a prominent dark green mark on the centre of the head, probably due to the jaws showing through the tissues. 3. The red band on the rhinophores was broad, and in one specimen occupied the centre of the organ. In the other specimen the basal half of the rhinophore was red-brown and the upper half white. 4, The foot was more bilobed, and produced into rounded lobes at the sides. The animals were active and restless, and progressed with ease on a flat surface contrary to Alder and Hancock’s surmise. Papille pale green, spotted with white and brown at their bases ; a few white spots were present on the head region, but I could not make out any “ white tubercles” in that region. GALVINA CINGULATA; A. & H. Voyage XCIV. Station 13. Inner Silver Pit. 43 fathoms. 1 specimen. Length 13 mm. The specimen was in a very perfect condition, and as it differs in several minor points from the plate and description of Alder and Hancock, a detailed description may be of interest. Body dull white, shaded, patched, blotched, and streaked with brown and olive-brown, much darker in the regions from which the papillx arise. The rhinophores smooth and very little shorter than the oral tentacles, a band of olive near the tip, and streaks of white down to the base. Oral tentacles similar. Head olive, spotted with white. Eyes not discernible. The region immediately behind the head streaked and lined with dark olive-brown and spotted with white. NEW SERIES.—VOL, VIIl, NO. 2. Q D5 )95 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA Papille long, stout, and irregular in outline, set in 9 transverse rows, the first somewhat remote from the others and arising close behind the rhinophores, thickest near the summit, and terminating somewhat abruptly in a small point; the inner rows held more or less curved inwards; 5 or 6 papille in each row. The bases very pale, the “core” of light yellowish brown, irregularly and indistinctly tinged with olive, an olive band near the tip, which is white (due to numerous minute white crowded dots), or sometimes tinged with olive or yellow. A bare space down the centre of the back; posterior region pinkish fawn. Body rather narrow, foot as in Alder and Hancock’s plate. Tail shorter than their figure. The white spots on the body well marked, those on the rhinophores and papille less so. The specimen was living on a branch of Antennularia ramosa grow- ing upon a stone brought up by the conical dredge. The hydroid was crowded with yellow gonophores, and the animal was by no means conspicuous when extended with the body parallel with the stem, the general colour and form of the papille approximating closely to what was undoubtedly its natural environment. GALVINA PICTA, A. & H. Voyage XCII. Station 45. Sylt Outer Ground. 13 fathoms. 1 specimen. Voyage XCIII. Station 30. Hartlepool Grounds. 30 fathoms. 2 specimens. The specimens were of the normal colouration, that from CXII—45 was living upon a colony of Sertularia cupressina. GALVINA TRICOLOR (Forbes). Voyage XCIII. Station 96. Lat. 55° 50’ N. Long. 0° 35’ E. 45 fathoms. 4 specimens. Voyage XCIII. Station 99. Lat. 55° 48’ N. Long. 0°49’ E. 45 fathoms. 1 specimen. 7 Voyage XCIV. Station 11. Inner Silver Pit. 43 fathoms. 1 specimen. 5 XCV. .; 24. §S. edge of the Coal Pit. 13 fathoms. 1 specimen. Voyage XCVI. Station 18. Lat. 54° 16’ N. Long. 1° 46’ E. 23 fathoms. 1 specimen. Some variations were observable in the colours of the body and papille. In the younger specimens the yellow band near the tip of the papille was paler than in the adults, and in one case it was absent from some of the papille, though present in others; when absent the whole tip was white. bo DURING JULY AND AUGUST, 1907. 33 In some of the adult specimens the body was brownish and in others of a greenish yellow. The specimen from XCIV—11 had had a number of the papille torn off, and fresh ones were growing in their places. CORYPHELLA GRACILIS (A. & H.). Voyage XCIV. Station 45. Lat. 53° 22’ N. Long. 0° 34? E. 15 fathoms. 5 specimens. Voyage XCIV. Station 47. Lat. 53° 283’ N. Long. 1° 39’ KE. 143 fathoms. 1 specimen. XCIV—45. Length of specimens, 8, 7, 7, 7,and 6 mm. respectively. Living on Antennularia antennina and Sertularia argenta. Agreed in all particulars with Alder and Hancock’s description, as also did the specimen from Station 47, which, however, was living upon Zubularia larnyx. CORYPHELLA LINEATA (Loven). Voyage XCIII. Station 21. West of Brucey’s Garden. 40 fathoms. 3 specimens. Voyage XCIII. Station 23. Whitby Outer Rough. 36 fathoms. 7 specimens. Voyage XCIII. Station 25. Whitby Grounds. 34 fathoms. 6 specimens, 3 i be 30. Off Hartlepool. 30 fathoms. 1 specimen. fF es ‘5 32. N.of Hartlepool. A few specimens. - i » 93. Lat. 55° 21’ N. Long. 1°10’ W. 45 fathoms. 3 specimens. The colour of the papille varies somewhat in shade, lighter or darker chestnut-red or carmine; the white tips also may be either well demarcated, narrower or wider, or may be continued downwards for a little way in streaks and blotches. The papille arise from or about two lateral transparent ridges, which are more prominent in some individuals than others; the first pair of clusters are much the largest, and are somewhat compressed and taper rapidly to the tip. The posterior portion of the foot is broad, and capable of consider- able expansion; the animal attaches itself by this, the rest of the body swinging freely in the water (as in many other species). It can also crawl on the surface film. The radula agrees with the figure and description of Alder and Hancock. The food of the species appears to be Tubularia indivisa and T, larnyx. 234 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA CORYPHELLA RUFIBRANCHIALIS (Johnst.). Voyage XCIII. Station 21. W. of Brucey’s Garden. 40 fathoms. 2 specimens, Voyage XCIII. Station 23. Whitby Outer Rough. 36 fathoms. 5 specimens. ‘i ss » 9380, Off Hartlepool. 30 fathoms. Common. ae eV; » 24. S. edge of the Coal Pit. 13 fathoms. 1 specimen. With the exception of that from XCV—24, all the specimens obtained from the above, and a number of other stations off the coasts of Durham and Northumberland and to the N. of the Dogger Bank, etc., were referred when captured to the C. pellucida of Alder and Hancock. In size and external features almost all exactly agreed with the plate and description of those authors, but upon examining the radule it became evident that they must all be referred to the present species. Some 16 specimens were examined from XCIII—21, 23, and 30. Unfortunately specimens from the other stations had not been pre- served, so I can only conjecture that they were also referable to this species. All the radule examined agreed very closely, and many were identical with the figures and description of Alder and Hancock. Generally of a yellowish white, the central plate with usually 15 denticles, the central cusp strong; the laterals, as described by Alder and Hancock, “of an acute triangular form with the apex turned out- wards ;” the denticles on their inner margins, however, very irregular in size and number, in some cases 12 to 14 and of fair size, in others the same number but much smaller, in others again only 7 or 8 might be present upon the upper portion of the tooth. It is possible that specimens occur without any denticles on the laterals, and although the radula, figured by Alder and Hancock for C. pellucida, is of a different shape to any I examined, still the evidence, I think, supports the opinions of Bergh and Vayssiére, who unite these species. One specimen from XCIII—30 had a faint white bifurcating line on the head as in (@ lineata, and in another from the same station the head region was coloured as in C. landsburgii (A. & H.). Oral tentacles and rhinophores amethystine, and tipped with yellowish white; length, half an inch. Both these cases also support the views of Bergh and Vayssicre in uniting these species also with C. rujibranchialis. Tubularia indivisa and T. larnyx were in every case the habitat of the species, and when crawling along the stems among the colonies the animals very closely resembled their surroundings. Some of the specimens were 4 cm. and many 3 and 33 cm. in length. bo Sy) or DURING JULY AND AUGUST, 1907. CORYPHELLA SALMONACEA (Couth.). Voyage XCIII. Station 59. Lat. 55° 31’ N. Long. 0° 36’ W. 47 fathoms. 1 specimen. Voyage XCIII. Station 89. Lat. 55° 57’ N. Long. 0° 27’ W. 42 fathoms. 2 specimens. Voyage XCIII. Station 96. Lat. 55°50’ N. Long. 0° 35’ E. 45 fathoms. Very common. Voyage XCIII. Station 99. Lat. 55° 48’ N. Long. 0° 49’ E. 45 fathoms. Very abundant. ; Voyage XCIII. Station 101. Lat. 55° 48’ N. Long. 1° 40’ E. 40 fathoms. About 100 specimens. Voyage XCIII. Station 103. Lat. 55° 44’ N. Long. 1° 40’ E. 43 fathoms. Several specimens. Voyage XCVI. Station 1. Lat. 56°00’ N. Long. 3° 23’ E. 38 fathoms. 1 specimen. Length, 20 mm. for the largest; the greater number of specimens, 15 mm. Other measurements of a specimen of 20 mm. in length: height of body, 5 mm.; breadth, 5 mm; length of oral tentacles 5 mm.; rhinophores, 4 mm.; papille, 3-5 mm. (for the largest). Form—Body firm, foot rather narrow, produced at the angles into thin points, tapers gradually to a somewhat obtuse point at the tail. Oral tentacles broad and thick; rhinophores slightly wrinkled; eyes very small, placed behind the rhinophores ; papillae very numerous, the grouping obscure, continuous almost to the tip of the tail; a bare space continuous from head for three-quarters of the length of the back. Colours—Body and foot semi-pellucid white; oral tentacles and rhinophores of the same colour, with frequently a line of opaque white down the front, or in the rhinophores confined to the upper third; papille reddish brown or fawn coloured, with a very distinct white ring just below the tip, giving an “eyed” appearance when viewed from above; this white ring speedily disappears in preserved specimens. Dorsal area frequently tinged with reddish brown, a faint white line along the dorsal surface of the tail. Jaws very strong and of a dark horn colour. Radula triseriate, of 16 to 18 rows, pale yellowish white in colour. Central plate broad, central cusp long and strong, with 7 to 8 denticles on either side, curved inwards and of fair size. Laterals slender and acute, generally bearing 8 or 9 small and irregular denticles. Almost all the specimens obtained were adhering to the meshes of the trawl or dredge, so that it is not possible to state its natural 236 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA habitat. Few hydroids occurred in any of the hauls. These specimens differ from the majority of C. salmonacea in that the lateral teeth have only 8 or 9 denticles on their inner edges, while in typical C. salmonacea they are very numerous (See Bergh, Danish Ingolf KHa- pedition, Vol. II, Pt. 3, pp. 33-34, Pl. Iv, Fig. 19; and Pl. v, Fig. 9). The numerous, closely-set, small papille, from among which arise the ill-defined groups of larger ones, were a constant feature in all the speci- mens examined. FACELINA DRUMMONDI (Thompson). Voyage XCIII. Station 7. W. edge of the Hills. 23 fathoms. 1 specimen. x a » 986. Lat. 56° 20’ N. Long 0° 55’. 36 fathoms. 2 specimens. Voyage XCIII. Station 89. Lat. 55° 57’ N. Long. 0° 23’ W. 42 fathoms. 1 specimen. Voyage XCIV. Station 47. Lat. 53° 28?’ N. Long. 1° 39’ E. 144 fathoms. 1 specimen. XCIII—86. Head orange, with white blotches between the rhino- phores; back light orange, becoming patchy towards the tail, which was pellucid white, and had a white line to the tip. Oral tentacles long, somewhat wrinkled, orange, the tips lighter and spotted with white. Rhinophores laminated, dark orange, the tip white, and a white line down the front of the tip. Eyes situated in front of the rhinophores in one specimen and behind them in the other. Papille run on to the head around the rhinophores; many were missing, but those remaining were of a chestnut-maroon, with a prominent white ring below the pellucid tip, those nearest the rhinophores with a longitu- dinal white line on the front face, and the white ring absent. Length of animals, 15 and 20 mm. XCIII—89. The body lighter in colour and semi-transparent. Foot sharply angulated, propodium deeply notched; a white line on the foot angles. Oral tentacles twice the length of the rhinophores. Papille dark chocolate colour. XCIV—47. A young specimen + of an inch in length. Foot angles produced into long fine points. Occurred upon 7'ubularia larnyx. LOMANOTUS GENEI, Verany. Voyage XCIII. Station 96. Lat. 55° 50’ N. Long. 0° 35’ E. 45 fathoms. 1 specimen. Length 14 mm. The rhinophores were of an orange-yellow colour, stout, and with about 15 closely-set lamine, the tip produced, truncated, and smooth ; DURING JULY AND AUGUST, 1907. 237 sheaths “calyx like,” extending for half the length of the rhinophores, the margin divided into a number of small blunt teeth. Margins of foot rounded. Body semi-transparent, tinged with pink; viscera yellowish and visible through the body wall. Faint pinkish brown lines on the epipodial processes. DOTO CORONATA (Gmelin). Voyage XCIV. Station 45. Lat. 53° 22’ N. Long. 0° 34?’ E. 15 fathoms. Common. Voyage XCV. Station 23. Knoll Deeps. 22 fathoms. 1 specimen. Those from XCIV—45 were living and spawning freely upon Gemel- laria loricata and Hydrallmania falcata, DOTO FRAGILIS, Forbes. Voyage XCIII. Station 62. Lat. 55° 31’ N. Long. 0° 19’ W. 36 fathoms. 3 specimens, Voyage XCIV. Station 13. Inner Silver Pit. 43 fathoms. 1 specimen. 55 is » 938 N. of Haisboro L.V. 14 fathoms. 1 specimen. ek GV I; » 20. Lat. 54° 11’ N. Long. 1° 40’ E. 22 fathoms. 1 specimen. XVIII—62. The three specimens varied in length from °5 to 1 em. One was upon Z'ubularia larnyx, and was much darker in colour than the other two, which were living and spawning on a species of Haleciwm. DENDRONOTUS ARBORESCENS (Miiller). An enumeration of the stations where this species was obtained is scarcely necessary, as it occurred throughout the entire area explored. Tubularia would appear to be its general habitat, and it is most plentiful where Z’ubularia is likewise abundant. ‘Three varieties are especially distinguishable. (a) The body transparent or yellowish white, and the dentritic pro- cesses opaque white, (4) a uniform, dull, semi-transparent pink, (c) red, with darker red or red-brown blotches. The last is the most general, and approximates well with the colonies of Zubularia on which it is usually found. More rarely specimens are found with the body much spotted with white. All these varieties are mentioned by Alder and Hancock. In one or two specimens a number of small wart-like projections were observable, scattered about the dorsal surface, particularly in the region between the rhinophores and the first pair of processes. 238 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA Several very young examples were examined, the smallest being 2 mm. in length; in this specimen the dentritic processes were simple, cylindrical, clavate, and incipiently branched in the first pair, which was much the largest; rhinophores plain and unbranched. TRITONIA HOMBERGI, Cuvier. This species was taken at a large number of stations. It appears to be generally distributed, though seldom abundant ; it was especially numerous where Alcyonium digitatwm abounded. The colouration varied from white, yellowish white and grey, to light or very dark brown. TRITONIA PLEBEIA, Johnst. Like the last, this species was found wherever Alcyoniwm digitatum was at all abundant, and was generally to be found creeping about the base of a colony, or between the fleshy lobes. Considerable difference exists between the individuals from the white and those from the orange colonies of Aleyonium; those from the white being of a pale hue, and those from the orange a warm orange-brown with darker markings. ARCHIDORIS TESTUDINARIA (A. & H.). Voyage XCIII. Station 59. Lat. 55° 31’ N. Long. 0° 19° W. 47 fathoms. 1 specimen, Length 45 mm.; general colour dark greenish yellow. Branchie 9, oi a dusky fringe Rhinophores short. Warts of two sizes, low and obtuse. Mantle ample, covering the sides and foot. The radula agreed with the figures given by Eliot (Journ. Mar. Biol. Assoc., Vol. VII, 1906, Pl. x1, Fig. 2). ARCHIDORIS TUBERCULATA (Cuvier). East Hartlepool. Rocks about low tide mark. 1 specimen. ACANTHODORIS PILOSA (Miller). Very common wherever Alcyonidiwm Gemeenadsiiar is at all abundant, and is widely distributed. Varying in size from a few mm. to nearly 5 em. in length. Usually pure white, sometimes grey, and occasionally brown or dusky. Spawn abundant upon Alcyonidium gelatinosum. DURING JULY AND AUGUST, 1907. 239 ACANTHODORIS SUBQUADRATA, A. & H. Voyage XCIII. Station 77. Off Holy Island. 32 fathoms. 1 specimen. The single example obtained agreed exactly with the description and plate of Alder and Hancock. LAMELLIDORIS BILAMELLATA (Linn.). Voyage XCIV. Station 47. Lat. 53° 2823 N. Long. 1° 39’ KE. 144 fathoms, 1 specimen. Voyage XCIV. Station 52. Lat. 53° 30’ N. Long. 1° 803’ E. 10 fathoms. _ 3 specimens. Voyage XCV. Station 24. S. edge of the Coal Pit. 13 fathoms. Fairly common. Voyage XCVI. Station 24. Lat. 54° 16’ N. Long. 1° 14’ KE. 31 fathoms. Fairly common. All the specimens but one were living among colonies of Balanus, upon stones of various sizes. In colour they were perfectly normal, and agreed so well with their environment as to be extremely difficult to detect, and repeated search- ing of the colonies of Balanus was necessary to obtain all the specimens present. The only marked variation was in the case of a specimen living upon a colony of Alcyonium digitatwm, growing on a stone covered with Balanus, on which normally coloured specimens of L. bilamellata were living. This one specimen was of a very clear white, the only dark marks being two obscure and shadowy patches on the mantle, and a slight dusky shade on the branchie. The largest specimens were not more than 16 mm. in length. It was observable that the branchiz increased in number with age. GONIODORIS CASTANEA, A. & H. Voyage XCIV. Station 54. The Sole Pit. Lat. 53° 40’ N. Long, 1° 28’ E. 47 fathoms. 1 specimen. Colour pinkish white, shaded with yellow. Rhinophores with yellowish laminz and yellow tips. Cloak more or less warted all over, the central and transverse ridges strongly warted, a double row on the central one. Jaws showed through the tissues of the head as a broad purple patch. Branchie 7, pinkish brown, with a few white spots, especially near the bases. The upper part of the foot paler than the mantle and with smaller tubercles. 240 NUDIBRANCHIATA COLLECTED IN THE NORTH SEA. The specimen was living upon a colony of Botryllus, which was attached to a large tube of Sabella pavonina, and upon which MER. Ayo VNeSaiv.. $1897 —99) ip. 95: Notes on Pontobdella muricata. By the Hon. Henry Gibbs. Journ. M.B.A. N.S. v. 1897-99, p. 330. Contributions to the Anatomy and Histology of Thalassema neptunt, Gaertner. By H. L. Jameson. Jena Fischer. 1899. Notes on the Marine Oligochaeta of Plymouth. By F. E. Beddard, m.a. Journ M.B.A. N.S.i. 1889-93, p. 69. Certain Points in the Structure of Clitellio. By F. E. Beddard, m.a. Proceed. Zool. Soc. 1888, p. 485. On Some British Species of Pachydrilus. By F. E. Beddard, m.a. Proceed. Roy. Phys. Soc. Edinburgh. 1889. The Nephridium of Lumbricus, with Remarks on the Nephridia of other Chaetopods. By W. B. Benham, psc. Quart. Journ. Mier. Sci. wolexxxat..) LSOlepi 293; The Amphinomidae, Aphroditidae, Polynoidae, and Sigalionidae of Plymouth and the English Channel. By T. V. Hodgson. Journ. M.B.A. N.S. vie L900; p: 218: On the Nephridia of the Polychaeta, 11. By E. 8S. Goodrich. Quart. Journ. Micr. Sci., xliii, 1900, p. 699. List of Polychaets taken at Plymouth. (Report on the Occupation of Table.) By Florence Buchanan, B.sc. Rep. Brit. Assoc. 1892. The Anatomy and Classification of the Arenicolidae, with some observations on their post-larval stages. By F. W. Gamble and J. H. Ashworth. Quart. Journ. Micr. Sci., xliii. 1900, p. 419. Report on Nerves of Arenicola, Nereis, etc. By F. W. Gamble, m.sc. Report Brit. Assoc. 1898, p. 584. The Post-larval Stage of Arenicola marina. By W. B. Benham, pD.sc. Journ. M.B.A. NS. iii. 1893-95, p. 48. 258 LIST OF PUBLICATIONS On a Blood-forming Organ in the Larva of Magelona. By Florence Buchanan, B.Sc. Report. Brit. Assoc. 1895, p. 469. Pallasia murata, nu. sp.: A New British Sabellarian. By E. J. Allen, D.sc. Journ. M.B.A. N.S. vii. 1904-06, p. 299. Observations on the Habits of the Onuphidae. By A. T. Watson. Trans. Liverpool Biol. Soc., vol. xvii. 1903, p. 303. The Anatomy of Poecilochaetus. By E. J. Allen, p.sc. Quart. Journ. Mier. Ser vol: xlvain. i 1 9045 our 9) Notes on the Anatomy of Dinophilus (with Plates IX. and X.). By S. B. Harmer, wa. Jour. M.B.A. N.S. i. |) 1889-90) (p. 1 19; On the Structure of the Nephridia of Dinophilus. By Cresswell Shearer. Quart. Journ. Mier. Sci., vol. 1. 1906, pp. 517. NEMERTINES AND TURBELLARIA. A list of the Nemertines of Plymouth Sound. By T. H. Riches, B.a. Journ, MBIA. N.S. i)).1893-95, ‘p:. 1. A New British Nemertine. By T. H. Riches, B.a. Journ. M.B.A. N.S. ii. 1891-92, p. 284. Description of a New Species of Nemertine. By J.C. Sumner. Ann. and Mag. Nat. Hist. (6), vol. xiv. 1894. On Two New British Nemerteans. By R. C. Punnett, m.a. Quart. Journ. Micr. Sci., xliv. 1901, p. 547. Contributions toa Knowledge of British Marine Turbellaria. By F.W. Gamble, B.Sc. Quart. Journ. Micr. Sci., vol. xxxiv. 1892-93, p. 433. The Turbellaria of Plymouth Sound and the Neighbourhood. By F. W. Gamble, B.sc. Journ. M.B.A. N.S. ii. 1893-95, p. 30. ECHINODERMS. Notes on the Echinoderms collected by Mr. Bourne in Deep Water off the South-west of Ireland in H.M.S. Research. By F. Jeffrey Bell, m.a. Journ. M.B.A. N.S.1i. 1889-90, p. 324. The Organogeny of Asterina gibbosa. By E. W. MacBride, mM.a. Proceed. Roy. Soce., vol. liv. 1893, p. 431. The Development of Asterina gibbosa. By E. W. MacBride, M.a. Quart. Journ. Micr. Sci, vol. xxxviil. 1895-96, p. 339. Report on the Work done during the Occupation of the British Association Table at Plymouth, June, 1905. (Development of Ophiothrix fragilis). By E. W. MacBride, F.r.s. Report Brit. Assn. South Africa, 1905, p. 183. The Growth of the Oocyte in Antedon: a Morphological Study in Cell- Metabolism. By G. C. Chubb, p.sc. Proceed. Roy. Soc. B. 519. 1906, p. 384. See also Phil. Trans. Roy. Soc. Ser. B., vol. 198. 1906, p. 447. On some Bipinnariae from the English Channel. By W. Garstang, M.a. Quart. Journ. Micr. Sci., vol. xxxv. 1894, p. 451. On the Echinoderm Fauna of Plymouth. By J.C. Sumner. Report. Brit- Assoc. 1895, p. 471. ‘ RECORDING RESULTS OF RESEARCHES. 259 The Development of Echinoids. Part I. The Larve of Eehinus miliaris and Echinus esculentus. By Prof. E. W. MacBride, mM.a. Quart. Journ, Micr. Sci., vol. xlii. 1899, p. 335. The Development of Echinus esculentus. By E. W. Macbride. Proc. Roy. Soc., 68, p. 268. Also Phil. Trans. Roy. Soc., 1903, p. 285. The Rearing of Larve of Echinidae. By Prof. E. W. MacBride, m.a. Report Brit. Assoc., 1899. Notes on the Rearing of Echinoid Larvee. By Prof. E. W. MacBride, m.a. Journ. M.B.A., vol. vi. 1900, p. 94. : On some Parasites found in Hehinus esculentus, L. By A. E. Shipley. Quart. Journ. Mier. Sci., xliv. 1901, p. 281. Notiz iiber die Excretion der Holothurien. By P. Barthels, pH.p. Zool. Anzeiger. 1895, p. 493. On Cucumaria Montagui, Fleming. By A. M. Norman, F.r.s. Ann. Mag. Nat. Hist. Ser. 7, vol xvi. 1905, p. 352. ‘Note on Two Species of Cucwmaria from Plymouth, hitherto confused as C. Montagui (Fleming): C. Normani, n. sp., and C. Saxicola (Brady and Robertson). By S. Pace. Journ, M.B.A, N.S. vii. 1904-06, p. 305. COELENTERATES. Beitrage zur Kenntnis der Spermatogenese bei den Colenteraten. By W. M. Aders, Px.D. Zeitsch. Wiss. Zool., vol. 74. 1893, p. 81. Tealia tuberculata, Cocks: a Study in Synonymy (with Plate XIX.) By J. T. Cunningham, m.a. Journ. M.B.A. N.S. i. p. 205. Some preliminary Notes on the Anatomy and Habits of Aleyontwm digitatum. By 8S. J. Hickson, m.a. Rep. Brit. Assoc. 1892. The Anatomy of Alcyoniwm digitatum. By Prof.S.J. Hickson, r.r.s. Quart. Journ. Mier. Sci., vol. xxxvil. 1894-95, p 343. Report on Mr. J. H. Wandsworth’s collection of material for the Study of the Embryology of Aleyonium. By Prof. 8S. J. Hickson, r.r.s. Report Brit. Assoc. 1898, p. 585. Notes on the Maturation of the Ovum of Aleyonium digitatum. By M. D. Hill, m.a. Quart. Journ. Mier. Sci., vol. xliv. 1905, p. 493. Virgularia mirabilis. By W. P. Marshall. Journ. M.B.A. N.S.in. 1893-95, p. 335. Notes on the Hydroids of Plymouth (with Plate XXVI.). By G. C. Bourne, Ma. Journ. M.B.A. N.S.i. 1889-90, p. 321. Tektonische Studien an Hydroidpolypen. Von Hans Driesch. Jenaische Zeitschrift. Vols. xxiv. and xxv. On some Points in the Histology and Development of Myriothela phrygia. By W. B. Hardy, B.a. Quart. Journ. Micr. Sci., vol. xxxii. 1891, p. 505. Notes on Plymouth Hydroids. By Prof. C. C. Nutting. - Journ. M.B.A. N.S. iv. 1895-97, p. 146. Notes on the Reproduction of Plumularian Hydroids. By Prof. C. C. Nutting. American Naturalist, Nov., 1895, p. 966. 260 LIST OF PUBLICATIONS Notes on Plymouth Hydroids. By Prof. C. C. Nutting. Bull. Lab. Nat. Hist: lowaene Mol. av. No. dyipsl. On Three New Species of Hydroids and one new to Britain. By Prof. C. C. Nutting. Ann. and Mag. Nat. Hist. (7) i. 1898, p. 362. On Tubularia crocea in Plymouth Sound. By E. T. Browne, B.a. Journ. M.B.A. N.S. v. 1897-99, p. 54. On British Hydroids and Medusae. By E. T. Browne, 8.4. Proceed. Zool. Soc. London. 1896, part 11. p. 459. On British Medusae. By E. T. Browne, B.a. Proceed. Zool. Soc. London. 1897, p. 816. On Keeping Medusae Alive in an Aquarium. By E. T. Browne, B.a. Journ. M.B.A. N.S. v. 1897-99, p. 176. Saphenia mirabilis, Haeckel. By J. T. Cunningham, m.a. Journ. M.B.A. N.S. ii. 1891-92, p, 194. On a Species of Siphonophore observed at Plymouth. By J. T. Cunning- ham, M.a. Journ. M.B.A. N.S. i. 1891-92, p. 212. Muggica atlantica. By J. T. Cunningham, m.a. Journ, M.B.A. N.S. i. 1891-92, p. 398. : On the Distribution and the Migrations of Muggicwa Atlantica, Cunningham, in the English Channel, the Irish Sea, and off the South and West Coasts of Ireland in 1904. By L. H. Gough, Ps.p., Conseil Perm. Internat. pour Explor. d. 1. Mer. Publications.de Circonstance, No. 292" 190d 2pe I: SPONGES. Notes on Plymouth Sponges. By George Bidder. Journ. M.B.A, N.S. vi. 1902, p. 376. Note on a Sieve-like Membrane across the Oscula of a Species of Lewcosolenia. By E. A. Minchin, m.a. Quart. Journ. Micr. Sci., vol. xxxiil. 1892, p. 251. The Characters and Synonymy of the British Species of Sponges of the Genus Leucosolenia. By E. A. Minchin, m.a. Proceed, Zool. Soc. Lond. vol. ii. 1904, p. 349. The Collar-cells of Heterocoela. By George Bidder. Quart. Journ. Micr. Sci., vol. xxxviii. 1895-96, p. 9. The Skeleton and Classification of Calcareous Sponges. By George Bidder. Proceed. Roy. Soc., vol. Ixiv. 1898, p. 61. Studies in Spicule Formation. Parts i-iv. By W. Woodland. Quart. Journ. Micr. Sci., vol. xlix. 1905, pp. 231 and 533. Studies in Spicule Formation. By W. Woodland. v.—The Scleroblastic Development of the Spicules in Ophiuroidea and Echinoidea, and in the Genera Antedon and Synapta. vi.—The Scleroblastic Development of the Spicules in some Mollusca, and in one Genus of Colonial Ascidians. Quart. Journ. Mier. Sci., vol. li. 1907, pp. 31-53. A Preliminary Consideration as to the possible Factors concerned in the Production of the various Forms of Spicules. By W. Woodland. Quart. Journ, Micr. Sci., vol. li. 1907, pp. 55-79. RECORDING RESULTS OF RESEARCHES. 261 PROTOZOA Contributions to the Life-History of the Foraminifera. By J. J. Lister, m.a. Phil. Trans. Roy. Soc. Vol. clxxxvi. 1895, p. 401. The Foraminifera of the Exe Estuary. By R. H. Worth. Journ. M.B.A. vi. 1902, p. 336. Observations on the Gregarines of Holothurians. By E. A. Minchin, B.a. Quart. Journ. Micr. Sci., vol. xxxiv. 1893, p. 279. Life History of Sporozoa. By H. M. Woodcock, 8.8c. Brit. Assoc. Report, Belfast, 1902. On Myxosporidia in Flat-fish. By H. M. Woodcock, B.sc. Report for 1903 on the Laneashire Sea Fisheries Laboratory, p. 46. On Cystobia trregularis (Minch.) and Allied “‘ Neogamous” Gregarines. By H. M. Woodcock, B.sc. Arch. Zool. Expér. et Gén. Notes et Revue, 1904, No. 8. The Life-Cycle of ‘‘Cystobia” trregularis (Minch.), together with Observations on other ‘“‘ Neogamous” Gregarines. By H. M. Woodcock, B.Sc. Quart. Journ. Micr. Sci., vol. 1. 1906, p. 1. FAUNISTIC AND GENERAL PAPERS. Preliminary Report upon the Fauna and Flora of Plymouth Sound. By Walter Heape, M.A. Journ. M.B.A. Old Series, No. 2. 1888, p. 194. Notes on the Marine Invertebrate Fauna of Plymouth for 1892. By W. Garstang, M.a. Journ. M.B.A. N.S. ii. 1891-92, p. 333. Faunistic Notes at Plymouth during 1893-94. I. Faunistic Records, p. 212. II. Notes on the Breeding Seasons of Marine Animals at Plymouth, p. 222. III. Materials for a Calendar of the Floating Fauna, p. 229. By W. Garstang, M.a. Journ. M.B.A. N.S. iii. 1893-95. On some New or Rare Marine Animals discovered on the Coast of Devonshire. By W. Garstang, m.a. Trans. Devon. Assoc. 1892, p. 377. Notes on the Plankton observed at Plymouth during June, July, August, and September, 1892. By E. J. Bles, psc. Journ. M.B.A. N.S. ii. 1891-92, p. 340. Faunistic Notes, January to June, 1895. By E. J. Allen, Bsc. Journ. M.B.A. N.S. iv. 1895-97,. p 48. Notes on Dredging and Trawling work during the latter half of 1895. By E. J. Allen, B.sc. Journ. M.B.A. N.S. iv. 1895-97, p. 164. Notes on the Pelagic Fauna at Plymouth, August—December, 1895. By T. V. Hodgson. Journ. M.B.A. N.S..iv. . 1895-97, p. 173. On the Changes in the Pelagic Fauna of Plymouth during September, 1893. and 1895. By E. T. Browne, B.a. Journ. M.B.A. N.S. iv. 1895-97, p. 168. On the Pelagic Fauna of Plymouth, September, 1897. By E. T. Browne, B.a. Journ. M.B.A. N.S. v. 1897-99, p. 186. On the Fauna and Bottom-deposits near the 30-fathom line from the Eddystone to Start Point. With seven Tables and sixteen Charts. By E. J. Allen, B.Sc. Journ, M.B,A. N.S, v. 1897-99, p. 365. 262 LIST OF PUBLICATIONS The Fauna of the Salcombe Estuary. By E. J. Allen, D.Sc., and R. A. Todd, B.Sc. Jourh. M.B.A. N.S. vi. 1900, p. 151. The Fauna of the Exe Estuary. By E. J. Allen, p.sc., and R. A. Todd, B.8c. Journ. M.B.A. N.S. vi. 1902, p. 295. Plymouth Marine Invertebrate Fauna: Being Notes of the Local Distribution of Species occurring in the Neighbourhood. Compiled from the Records of the Laboratory of the Marine Biological Association. Journ. M.B.A. N.S. vii. 1904-06, p. 155. Report of a Trawling Cruise in H.M.S. Research off the South-west coast of Ireland. By G. C. Bourne, m.a., with addendum by the Rey. Canon Norman, F.r.s. Journ. M.B.A. N.S.i. 1889-90, p. 306. Report on the Surface Collections made by Mr. W. T. Grenfell in the North Sea and West of Scotland (with Plate XXV.). By G. C. Bourne, m.a. Journ. M.B.A. N.S. i. 1889-90, p. 376. Report on the Surface Drift of the English Channel and Neighbouring Seas for 1897. By W. Garstang, m.a. Journ. M.B.A. N.S. v. 1897-99. p. 199. Physical Investigations. By H. N. Dickson. Journ. M.B.A. N.S.i. 1891-92, pp. 159, 272. Notes on Meteorological Observations at Plymouth. By H. N. Dickson. Journ. M.B.A. N.S. ii. 1891-92, p. 171. Microscopic Marine Organisms in the Science of Hydrography. By Prof. P. T. Cleve. Journ. M.B.A. N.S. iv. 1895-97, p. 381. Plankton and Physical Conditions of the English Channel. First Report of the Committee, consisting of Prof. E. Ray Lankester (Chairman), Prof. W. A. Herdman, Mr. H. N. Dickson, and Mr. W. Garstang (Secretary), appointed to make Periodic Investigations of the Plankton and Physical Conditions of the English Channel during 1899. Report Brit. Assoc. 1899. Notes on the Physical Conditions existing within the Line from Start Point to Portland. By H. M. Kyle, psc. Journ. M.B.A. N.S..vi. 1903; p. 528. Report on the Physical Conditions in the English Channel, 1903. By Donald Matthews. Internat. Fish. Investigations. Mar. Biol. Assoc. Report 1, 1902-03. (Cd. 2670) 1905, p. 289. Report on the Plankton of the English Channel, 1903. By Lewis H. Gough, Ps.D. Internat. Fish. Investigations. Mar. Biol. Assoc. Report I. 1902-03 (Cd. 2670). 1905, p. 325. On the Oxidation of Ammonia in Sea Water. By G. P. Darnell-Smith. Journ. M.B.A. N.S. i. 1893-95, p. 304. On the Action of Nicotine on Certain Invertebrates. By Marion Greenwood. Journ. Physiol., vol. xi. 1890, p. 573. Notes on some Animal Colouring Matters. By C. A. MacMunn, m.a., M.D. Journ, M.B.A. N.S. i. 1889-90, p. 55. Contributions to Animal Chromatology. By C. A. MacMunn, ™.a., M.D. Quart. Journ. Micr. Sci., vol. xxx. 1890, p. 51. Photogenic Bacteria. By J. E. Barnard. Trans, Jenner Inst. Preven, Med. 1899, ser. ii. p. 81. RECORDING RESULTS OF RESEARCHES. 263 VARIATION. The Variations occurring in Certain Decapod Crustacea. I. Crangon vulgaris. By W. F. R. Weldon, m.a. Proceed. Roy. Soc., vol. xlvii., p. 445. Certain Correlated Variations in Crangon vulgaris. By Professor Weldon, F.R.S. Proceed. Roy. Soc. vol. li. 1892, p. 1. Certain Correlated Variations in Carcinus maenas. By Professor Weldon, F.RS. Proceed. Roy. Soc., vol. liv. 1893, p. 318. An Attempt to Measure the Death-rate due to Selective Destruction of Carcinus maenas, with Respect to a Particular Dimension. By Prof. Weldon, F.r.s. Proceed. Roy. Soc. vol. lvii. 1895, p. 360. Remarks on Variation in Animals and Plants. By Prof. Weldon, F.r.s. Proceed. Roy. Soc. vol. vii. 1895, p. 379. Presidential Address to the Zoological Section (on Natural Selection and Variation). By Professor Weldon, r.r.s. Report Brit. Assoc. 1898. On the Variation of the Tentaculocysts of Aurelia aurita. By E. T. Browne, B.A. Quart. Journ. Micr. Sci., vol. xxxvu. 1894-95, p. 245. Variation in Aurelia aurita. By E. T. Browne. Biometrica, Vol. 1, No. 1, page 90, On the Variation of Haliclystus octoradiatus. By E. T. Browne, B.A. Quart. Journ. Micr. Sci., vol. xxxviil. 1895-96, p. 1. Preliminary Report of the Results of Statistical and Ichthyological Investiga- tions made at the Plymouth Laboratory. By Georg Duncker, pPx.p. Journ. M.B.A. N.S. v. 1897-99, p. 172. Quantitative Studies in the Evolution of Pecten. III. Comparison of Pecten opercularis from three localities of the British Isles. By C. B. Daven- port. Proceed. American Acad. Arts and Sci., vol. xxxix. 1903, p. 123. Evolution without Mutation. By C. B. Davenport. Journ. Experim. Zool., vol. i. 1905, p. 137. Botanical Publications. The Flora of Plymouth Sound and Adjacent Waters (with a woodcut). By Prof. T. Johnson, B.sc. Journ. M.B.A. N.S. i. 1889-90, p. 286. On the Systematic Position of the Dictyotaceae, with special reference to the Genus Dictyopteris, Lamour. By. Prof. T. Johnson, B.sc. Journ. Linn. Soc. Botany, vol. xxvii. 1890, p. 463. Studies in the Dictyotaceae. III. The Periodicity of the Sexual Cells in Dictyota dichotoma. By J. Li. Williams. Annals of Botany, vol. xix. 1905, p. 531. Observations on Brown and Red Sea-weeds. By Prof. T. Johnson. Rep. Brit. Assoc. 1890. On the Structure of the Thallus of Delesseria sanguinea (with Plates XVII. and XVIII.). By M. C. Potter, m.a. Journ. M.B.A. N.S. i. 1889-90, p: LG. The Callosities of Nitophyllum versicolor. By Prof. T. Johnson. Journ. toy. Dublin Soc. 1892. NEW SERIES.—VOL. VIII. No, 2. Ss 264 LIST OF PUBLICATIONS. Observations on the Phaeozoosporeae. By Professor T. Johnson. Ann, Bot., vol. v. 1891. Halosphaera viridis, Schmidt. By H. Thompson, B.a. Journ. M.B.A. N.S.1. 1889-90, p. 341. The Polymorphy of Cutleria multifida. By A. H. Church, p.a. Ann. Bot., vol xu. No.45. 1898sp.075: Algological Notes, by G. Brebner. Journ. M.B.A. N.S. iv. 1895-97, PO -w02- 286, On some Endophytic Algae. By A. D. Cotton. Journ. Linn. Soc. Botany, vOlexxxval. L906, pu2ss: List of Institutions which have been supplied with specimens of marine animals and plants by the Marine Biological Associa- tion during two years ending 31st May, 1907. I.—UNIVERSITIES, UNIVERSITY COLLEGES, AND RESEARCH LABORATORIES. Department of Comparative Anatomy, Oxford. Geological Laboratory, Oxford, Zoological Laboratory, Cambridge. Balfour Laboratory, Cambridge. The Botany School, Cambridge. The University of London. Bedford College for Women, London. Birkbeck College, London. Charing Cross Hospital Medical College. Guy’s Hospital Medical College. King’s College, London. The Lister Institute of Preventive Medicine. London Hospital Medical School. London School of Medicine for Women. Middlesex Hospital. Royal College of Science, South Kensington. Royal Veterinary College, Camden Town. 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Municipal Technical School, Rochdale. Central Secondary School, Orchard Lane, Sheffield. St. Mary’s Hall, Stonyhurst. Central Technical Schools, Truro. Municipal Secondary School, West Bromwich. Eton College, Windsor. Grammar School, Wirksworth. — Transvaal Technical Institute, Johannesburg, PUBLICATIONS OF THE ASSOCIATION. — ++ ee ee = - - Journal of the Marine Biological Association. OLD SERIES. No. 1, August, 1887 (only a few copies left, reserved for Libraries). No. 2, August, 1888. Price 1s. New Series (Royal 8vo). Volume I., 1889-90, 472 pp., 28 plates. Volume IT., 1891-2, 410 pp., 14 plates. Volume IIT., 1893-4, xxxviii. and 458 pp., 5 plates and 25 woodcuts. Volume IV., 1895-7, iv. and 425 pp. Volume V., 1897-9, 550 pp. and 16 plates. Volume VI., 1899-1903, 676 pp., 3 charts and 7 plates. Volume VII., 1904-6, 588 pp., 1 chart and 12 plates. Volume VIII, No. 1. Separate numbers (generally 4 to one volume), in wrappers, 3s. 6d.; to Members, 2s. 8d. London Agents: Messrs Dunavu & Co., 37 Soho Square, W. Cloth 4to, 150 pp., 18 plates (12 colowred), A TREATISE ON THE COMMON SOLE. J. T. CUNNINGHAM, M.A, F.RB.S.E., Late Fellow of University College, Oxford; Naturalist to the Association. Price to Members, 20s.; to Non-Members, 25s. Medium 8vo, 368 pages. 159 Illustrations and two Maps. Price 7s. 6d. net. (Macmillan &: Co., London.) THE NATURAL HISTORY OF THE MARKETABLE MARINE FISHES OF THE BRITISH ISLANDS. Prepared expressly for the use of those interested in the Sea-fishing Industries, BY J. T. CUNNINGHAM, M.A., FORMERLY FELLOW OF UNIVERSITY COLLEGE, OXFORD 5 NATURALIST ON THE STAFF OF THE MARINE BIOLOGICAL ASSOCIATION. GGith jPreface bp EK. RAY LANKESTER, MOA, LL.D., F-R:S. PROFESSOR OF COMPARATIVE ANATOMY IN THE UNIVERSITY OF OXFORD, PUBLICATIONS OF THE INTERNATIONAL COUNCIL FOR THE STUDY OF THE SKA. BULLETIN DES RESULTATS ACQUIS PENDANT LES COURSES PERIODIQUES, PUBLISHED QUARTERLY. Price per Volume of Four Numbers, 18 Kroner (£1). RAPPORTS ET PROCES-VERBAUX DES REUNIONS. Vous: 1.=1X., 1902=7- Price per volume, from Kr. 4 to Kr. 15. BULLETIN STATISTIQUE. DES PECHES MARITIMES. Vou. I., 1903-4. Kr. 10. PUBLICATIONS DE CIRCONSTANCE. Nos. 1-41, 1903-7. Price per Number, from Kr. 0.50 to Kr. 3. Published on behalf of the International Council BY ANDR. FRED. HOST ET FILS, COPENHAGEN. [ 269 ] Plankton Studies in Relation to the Western Mackerel Fishery. By G. E. Bullen. With Six Charts (Plates XVIII-XXIII), two Figures in the Text and Tables I-V. I. METHODS. THE researches here described extended for intermittent periods over the years 1906 and 1907, and were primarily intended to embrace inquiry into the food problem of Pilchard, Herring, and Mackerel frequenting the western part of the English Channel. The observa- ~ tions now recorded form, therefore, a part of a wider series. Most of the information referring to the condition of the fishery throughout the spring season of the two years was collected at Newlyn and Plymouth, by systematic inquiry amongst the fishermen. Other information was derived from the market reports of the Fish Trades Gazette and other journals, and from Mr. Mathias Dunn of Newlyn, who kept the fishery constantly under observation. The samples of plankton and stomach material were obtained from various sources. Some were taken by myself at sea from fishing-boats or from the Oithona, others by fishermen; whilst a good deal of the stomach material was got from systematic collections made at Ply- mouth and Newlyn from catches landed at those ports. In addition to the plankton samples mentioned above, certain samples taken at the western stations during the international cruises were also ex- amined and the results utilized. The plankton was collected for the most part by a compound tow- net embodying in its construction Swiss bolting silk of two sizes of mesh, viz. (2) 18 holes per 1 cm., the average length of a hole being ‘056 cm. and the average breadth being ‘036 cm., and (d) 70 holes per 1 em. The surface hauls were usually made for ten minutes. The contents of the net were filtered through a net-bag constructed of the fine silk mentioned above, and the product preserved in 5 % formalin. NEW SERIES.—VOL, VIII. NO. 3. OCTOBER, 1908. £ ‘oh, 270 PLANKTON STUDIES IN RELATION TO In certain cases the samples were collected by two separate nets, of coarse and fine mesh respectively. As this paper does not deal with plankton other than in its direct bearing upon mackerel food, it has been considered desirable, for pur- poses of easy reference, to include the surface hauls with those taken from bottom to surface (oblique) under one column for each position noted on the Plankton Tables (Tables I, I1). In thus combining the analyses of the surface and oblique hauls, it may be mentioned that the comparative signs (which are those adopted in the International Plankton Investigations) placed against the Phytoplankton species are those derived from the analysis of the surface haul, whilst for Zoo- plankton the higher of the two values recorded for the surface and oblique hauls is used. In the determination of the plankton samples, a general examination was first made under magnification x48 and x160 in a shallow trough. The phytoplankton was subsequently examined under cover- slip with higher powers, x 520 to x 824, ete. In the greater number of cases six stomachs were collected from every catch and preserved in 10 % formalin. The contents of each were subsequently washed out into Petrie dishes and examined in a similar manner to that described for plankton. The whole of the sample, unless very bulky, was examined. Other modifications of detail with reference to stomach samples are explained under a later heading, page 273. My thanks are largely due to Dr. E. J. Allen, who has materially assisted me throughout the investigation and in the preparation of this paper; also to Mr. Mathias Dunn, for much valuable help in the collection of observations and material. I here also desire to express my thanks to Mr. Howard Dunn, Mr. D. J. Mathews, Dr. L. H. Gough, and Mr. W. Bygrave, for assistance in the collection or identification of material, and to Mr. A. E. Hefford for help in the preparation of this paper. Il. THE WESTERN SPRING MACKEREL FISHERY. THE factors, which influence the inshore migration of mackerel in greater or less abundance, have long been the subject of inquiry. That the purpose of spawning is the primary object of such migration has been admitted, but it still remains to show reasons for the greater or less extent of this migration, which from a commercial standpoint, under the present system of drift fishing, is equivalent to a good, bad, or indifferent season. Many previous authors have shown that THE WESTERN MACKEREL FISHERY. Difad plankton forms the main food of mackerel during the shoaling season, and the examination of more than four hundred stomachs of mackerel taken in the British Channel and extreme western part of the English Channel, during the present investigations (1906-7), has shown agreement with this result. As suggested by several previous authors on the subject, it appears possible that from a study of this food some light may be thrown upon the factors which govern the fluctuations in the mackerel fishery during the spring shoaling season. The object of this paper, therefore, is to show, from the information and observations at our disposal, whether there is a demonstrable correlation between the distribution of plankton or mackerel food, and the extent of migration. It has already been stated that over four hundred stomachs have been examined during the present researches. These were taken in 1906-7 from fish caught in the Bristol Channel and in the English Channel from Plymouth to west of Scilly, during the three months which constitute the more important part of the spring fishery, viz. April, May, and June. The result of the analyses of these stomachs will be found in the Plankton and Food Tables which are appended. From an examination of these tables it will be seen that on no occa- sion has an instance occurred of material, other than plankton, being observed in the stomachs of fish caught during the shoaling season in the extreme western part of the area under consideration. In the - eastern part, however (see Table V), it will be seen that the plankton forming the principal food was gradually supplemented, as the season advanced, with young fish and adult Crystallogobius ailsont. From information derived from the weekly market reports published in the Fish Trades Gazette, and from statements made to me by local fishermen at Plymouth and Newlyn, it would appear that, although drift fishing had been carried on in the Bristol Channel and elsewhere since the beginning of February until April in 1906 and 1907, the catches made were irregular and comparatively small. Fishermen and others agreed in stating that this was due to the fact, that there appeared to be no regular shoaling at the surface during these three months. That mackerel did occur, however, in the inshore waters at this time at the surface is evinced by the fact that fair catches of hook fish were made constantly during the early months of the two years, as shown by the market reports, and by the writer’s personal ob- servations. Fishermen seem to be agreed that shoaling mackerel will not take a bait: and a consideration of the above facts tends to suggest that in 272 PLANKTON STUDIES IN RELATION TO these early spring months mackerel may be present at the surface but are disseminated over a wide area. A careful comparison of the plankton results for the February cruises, shown in the Bulletins Conseil Inter- national pour Texploration de la Mer, shows that, at the western mid- Channel and Bristol Channel stations (E. 5 and E. 6, the only two fall- ing within the fishing area), plankton generally has reached a minimum in comparison with other quarterly results. It is desirable at this point to state that, for the purpose of comparison in this and other cases, an arbitrary numerical value was substituted for the comparative signs employed in the tables, viz. + =10, c=100, cc=500, the signs “r” and “rr” being disregarded. In the present instance comparison was made for all the years since the commencement of the international investigations, and this condition appeared to be invariably the same. This point is further supported by certain observations taken during the present investigations (Nos. 2, 3, 4, 5, 6, Table I). These two main facts considered together cannot, however, be offered as sufficient evidence that mackerel do not shoal closely at the surface until there is a sufficiency of plankton to form food for their support without much individual effort, especially in view of the fact that mackerel are known to be shoaling densely at the bottom off Start Point in the early part of the year, and, as far as our present observations extend, are feeding there upon plankton. Possibly, how- ever, it may be suggested reservedly that a lack of plankton may exercise a retarding influence upon the shoaling of fish already at the surface, which are disseminated over a wide area, of the presence of which evidence has already been given. Further, attention has already been drawn to the fact that in the Plymouth to Lizard area in 1907 larger food material was observed, in gradually increasing quantity as the season advanced, from the end of April onwards. Throughout July, 1907, from the writer’s personal observations, the plankton in the Plymouth area was observed to decrease very materially in quantity. In the previous month, the tow-nettings brought to the Laboratory at Plymouth from within and outside the Sound for the use of students, and for the Plymouth plankton records taken weekly, were composed mainly of Temora longicornis in extreme abundance. During the first few days of July, within the first week, the Copepod in question, from being ex- tremely abundant, rapidly disappeared from the tow-nettings, leaving the samples almost clear, for the time being, of animal life. No plankton observations were obtained from the western area during July, 1907; but, confining our attention to the Plymouth to Lizard area, it appeared that from all reports the shoals broke up at about this time and the hand-lining season commenced. It may, therefore, be sug- THE WESTERN MACKEREL FISHERY. aie gested, that, until individual effort on the part of the fish to secure food becomes necessary, the mackerel remain in shoals. These results tend to support the theory that mackerel feed upon plankton only when shoaling. Owing to a certain general similarity in the samples examined, it was found possible to tabulate the results of the analyses of the stomach material. These are given in the Plankton and Food Tables (III, IV, and V) which are appended. From nearly every position noted therein the contents of six stomachs were examined, and, by a system of adopting the highest comparative symbol placed against the different species throughout the series, a single sample was formed. This, in certain instances, is shown for comparison with a plankton sample collected on the same position as that from which the fish themselves were derived. It has proved convenient to arrange the results in three separate tables, viz. Western Area, 1906; Western Area, 1907; and Plymouth to Lizard Area, 1907. Lack of observation in this latter area in the earlier year has prevented the formation of a separate table for 1906. It will be seen that only those principal species, which occurred more or less regularly in the stomach contents, have been included in the tables. These comprise seven species of Copepods, viz. Acartia clausi, Calanus finmarchicus, Centropages typius, Metridia lucens, Paracalanus parvus, Pseudocalanus elongatus, and Temora longicornis, An examina- tion of the tables will show that of these species Calanus jinmarchicus, Pseudocalanus elongatus, and Temora longicornis are the most important. The other species, although persistently occurring in stomach contents, are hardly of sufficient importance for purposes of comparison. In addition to the Copepods there are included in the tables, Zoeae, Sagitta bipunctata and Orkopleura dioica. These species, together with the Copepods, constitute the principal forms of zooplankton observed in the stomach contents. For the Plymouth to Lizard area it was found necessary to include young fish, or Crystallogobius. The last item for consideration, which is noted on every table as ‘“ Phytoplankton, chiefly Phaeocystis globosa,” refers to the material largely found in mackerel stomachs in the early part of the season. This, upon examination, in many instances proved to be diatom detritus, consisting of the shells, spines, chromatophores, and the jelly-like substance associated with them, forming in a majority of cases a glairy mass of a dark green tint.* Associated with this material in a number of instances was a certain quantity of Phaeocystis * For the exact diagnosis of the nature of this material the writer is indebted to Mr, A. J. Mason-Jones, 274 PLANKTON STUDIES IN RELATION TO globosa, the exact proportion of which it was found impossible to gauge. In certain samples, however, owing to the absence of diatoms and other protophyta (Samples 68, 69, 93, 94, Tables III, LV), it was found possible to estimate the amount of Phaeocystis with more probability. It may be mentioned that Cunningham,* in describing the early spring food of mackerel, remarks, “ In some [stomachs] there occurred a quantity of the green slimy vegetable matter, which was then abun- dant in the sea.” During the examination of certain series of stomachs, instances have occurred where the contained food was deposited in layers (Samples Nos. 94, 120, 121, 123, 124, etc, Tables IV, V). Farran (Report on Sea and Inland Fisheries, Ireland, 1901, Part II, p. 122) records the same thing, and Mr. W. M. Tattersall informed the writer that he has frequently observed a similar condition in mackerel from the west of Ireland. Such a state of the stomach contents is specially obvious where the Pteropod Limacina retroversa (Flem.) occurs together with one or more species of Copepods, the dark colour of the former contrasting sharply with the bright orange tint of the latter. It has often been suggested that certain plankton organisms occur in shoals of varying extent. Now it is interesting to note in this connection, that many fishermen think that shoaling mackerel, ' when feeding, scarcely move at all, beyond maintaining their position against the current. The theory of the fish feeding, therefore, first in one shoal of plankton organism and then in another as they pass, may be suggested as an explanation of this phenomenon. The fact might also be due to the fish swimming first in one and then in another layer of water. By an examination of the Food and Plankton Tables it will be seen that the plankton organisms occurring in the stomach contents are common also to tow-nettings taken on the same position. In a majority of cases also, the relative proportions of individual species are similar in both, or nearly so. Occasionally differences occur. But in the examination of the large mass of material which is generally found in a mackerel stomach when plankton is abundant, it is often difficult to decide the comparative proportion of one species to another. This fact, together with that of the method of treatment already explained (see p. 273), will account for the differences which are occasionally shown between the analyses of stomach contents and those of plankton samples from the same locality. Although, however, certain species occurring in the tow-nettings are * Marketable Marine Fishes, p. 313. THE WESTERN MACKEREL FISHERY. 275 observed in the stomach material of fish from the same position, an exhaustive examination of a fair number of stomach samples has failed to show the presence of the same variety of organisms in the stomach, as occur in the tow-nettings taken on the same positions as the mackerel. Possibly this fact may be offered as additional evidence in support of the food-layer theory already mentioned. In the early part of April, 1906, as in the two preceding months, an unprofitable fishery had been carried on in the Bristol Channel by the greater number of the steam drifters. From fishermen’s reports this condition had, it appeared, continued since the commencement of the season without a single period of improved fishing. On the 20th of April, however, some good shoals were struck to the south-west of the Wolf by the sailing fleet. The greater number of the steam drifters at once left the Bristol Channel and commenced fishing in a semicircle to the south and south-west of Scilly. The result was that moderate but regular catches of ten thousand down were landed from this area, the fishing although light being general. The stomach contents of samples of these fish did not differ very materially from those of Bristol Channel fish (see Samples Nos. 66, 67, Table ITI). A line of plankton samples was taken at this time from Plymouth to the fishing area south-west of the Wolf, the chief aim being the determination of the relative quantities of zooplankton and phyto- plankton* present on the fishing area and adjacent waters. The analyses of the tow-nettings taken on 23rd and 24th April during this cruise (see Samples Nos. 11-20, Table I) are interesting when viewed in relation to the distribution of shoaling mackerel at the time. Briefly summarized, it appeared that from Plymouth to the Lizard phytoplankton in every example was in excess of zooplankton (Samples Nos. 11, 12, 13, and 20, Table I). In the single position in Mount’s Bay where tow-nettings were taken this was also the case (Sample No. 19, Table I), whereas in samples taken, on the approach to the fishing area and actually on the ground (Samples Nos. 14-17), there was a rapid decrease in phytoplankton, leading to a reverse of the former condition, ie. to an excess of zooplankton over phyto- plankton. It may be mentioned that the excess of phytoplankton over zooplankton was largely, though not entirely, due to the presence in the samples of large quantities of Phacocystis globosa, Scherffel. * Throughout this paper the word ‘‘ phytoplankton” must be understood as referring to the larger organisms, such as are recorded in the plankton tables of the International Bulletin. No investigations have been made on the minute plankton organisms which Lohmann has included under the term ‘‘ microplankton.” 276 PLANKTON STUDIES IN RELATION TO From a comparison of the tables it will be seen that the reverse condition was not brought about entirely by the decrease of the Phaeo- cystis, but also by the increasing number of the Copepods in the samples. During this cruise, through lack of time, only one position could be worked in the Bristol Channel (Sample No. 18, Table 1), which showed phytoplankton in excess of zooplankton. The same condition was observed in a sample taken at Sevenstones five days later. The positions of the stations on this cruise and the general distribution of samples taken during April, 1906, can be readily understood on refer- ence to the Distribution of Species Chart No. 1. Throughout the early part of April, 1907, from the fishermen’s reports it appeared that fairly regular catches had been landed from the Bristol Channel south-west of the Wolf, and also from twenty to thirty miles S.W. of the Lizard. Many fishermen declared, however, that the water lying within a ten-mile or wider limit from the coast from off Plymouth to Land’s End, was in that particular condition which they termed “ stinking,” and of a most unsuitable condition for the presence of mackerel.* In order to obtain observations in this affected area, and also to trace the varying proportions of zooplankton and phytoplankton on the fishing ground, a cruise was taken from Plymouth to ten miles 8.W. of the Wolf, and from thence to twenty miles north of the Longships, somewhat earlier than in 1906, viz. April 16th, 17th. The analyses of the tow-nettings taken (see Samples Nos. 41-8, Table IL) show a some- what similar condition to that observed in 1906, with certain impor- tant exceptions. The main differences lie in the excess of phyto- plankton extending farther westward past the Lizard (see Samples Nos. 41-5, Table II). This condition was largely due to Phaeocystis ; zooplankton occurring in excess of phytoplankton only in the sample taken farthest west, viz. ten miles 8.W. of the Wolf (No. 48, Table IJ). A more important feature, however, appears to lie in the conditions observed in the Bristol Channel samples (Nos. 46, 47, Table IL), where zooplankton occurred decidedly in excess of phytoplankton. For a synoptic view of these observations, showing the positions of stations, the reader is referred to Distribution of Species Chart No. IV. Now in drawing a comparison between the condition exhibited by the plankton and that by the fishery in April 1906 and 1907, it will be seen that in the former year, phytoplankton appearing in excess of zoo- plankton in the Bristol Channel, the fishery there was unprofitable ; whereas the reverse obtaining 8.W. of the Wolf, fair catches were * See note on ‘‘ Stinking Water,” p. 289. THE WESTERN MACKEREL FISHERY. 277 made there. In 1907, on the other hand, zooplankton was in excess of phytoplankton both in the Bristol Channel and also to the S.W. of the Wolf, in both of which areas good fishing was obtained. In considering these observations further, it is interesting to find that the most profitable fishing grounds lay outside the area in which phyto- plankton predominated, which suggests that mackerel during the shoaling season prefer an animal to a vegetable diet, and may be met with in quantity where such food is abundant. Further consideration of the Distribution of Species Charts IV to VI shows wider eastward distribution of shoaling mackerel as the season proceeded in 1907. An examination of the Plankton Tables Nos. I and II shows, more- over, that throughout the season, during 1906, phytoplankton was always in evidence, whereas in 1907 it entirely disappeared from the beginning of May onward until the close of the season. The official statistics of monthly landings, published by the Board of Agriculture and Fisheries show that the fishery in 1906 was phenomenally bad, whereas that of 1907 was very good. From these two facts it may be suggested that excess of phyto- plankton in inshore waters retards or rather limits the eastern migra- tion of the shoals first appearing west of Scilly. An examination of the official statistics of mackerel landings serves to show that, in the month of May, the quantity of mackerel caught has reached a maximum for the four months forming the more im- portant part of the spring fishery. The following table shows the figures from 1901-7 inclusive. The figures given represent the landings on the south and west coasts of England and Wales, which are sig- nificant for the western fishery, since comparatively few mackerel are taken elsewhere during the months dealt with. Table showing Official Returns of Mackerel landed on the south and west coasts of England and Wales, from March to June inclusive, in the years 1901-7. TOTAL IN HUNDREDWEIGHTS. IgoI. 1g02. 1903. 1904. 1905. - 1906. 1907. Maret, .2923,340. iy VSM i 225492 ... .78)/ 866) Lee NGSISZONI AN) 960a.2 18,769 April’ 5 39041 4 78,384, ..2 G0;190 ... 62;241 66 959,979 i...” (289779) 0... 48,107 May . 169,020 ... 169,857 ... 152,753 ... 199,884 ... 378,157 ... 108,273 ... 222,151 sencees se dUbon tg 45669... 65,005 .:, 108,822... 55.21 —. 49,749...” °57.383 As these figures are taken over a fair number of years it may be assumed that during May, under normal conditions, the fishery is at its height. In May also the maximum number of boats are generally 278 PLANKTON STUDIES IN RELATION TO fishing, and during the latter part of the period considered there is no reason to suppose that the number of boats has greatly altered. The fluctuation, as shown by the official figures, in consideration of the usual fair-weather conditions during this month, is less liable to be influenced by causes other than the greater or less extent of migration. On reference to the above table it will be seen that in May, 1906, the landings touched a minimum for the seven years; whereas, al- though the figures in no way compare with those of 1905, the May landings for 1907 are suggestive of a good season. The good May fishing of 1907 as opposed to the bad of 1906 forms a useful compari- son when we come to consider plankton conditions of the same period in these two years. From an examination of the daily market reports published in the Fish Trades Gazette, it would appear that in 1906 the fishery was gradually improving throughout May until the last week, when, after a short period of improved conditions, it began rapidly to decline, and remained depressed until the end of the season. In 1907, from information derived from the same source, and from observations taken at Newlyn by Mr. W. Bygrave, it appeared that heavy landings of mackerel took place during the first and second weeks in May. The market was several times glutted; and there is every reason to suppose that, had not a short spell of bad weather intervened, in which the men temporarily lost sight of the shoals, the landings would have been considerably greater than they appear to be from the official statistics. However, despite the unfavourable com- parison between the figures for May, 1905, and those of 1907, from all accounts there is every reason to consider the latter year to have been an excellent season. In reviewing the plankton conditions generally, it should first be pointed out that throughout May, 1906, phytoplankton was present in fair quantity in every sample taken during the month on the fishing grounds (see Table 1). In 1907, on the other hand, it had almost completely disappeared, and as may be seen from the Plankton Tables (Table II), zooplankton was represented by merely a few species of Copepods in extreme abundance. The comparative symbol. “cc” shown on the tables for certain samples (Nos. 52, 53, 54, 55) hardly sufficiently indicates the large quantities of the species occurring in the sample. In comparing the plankton conditions during May of these two years, it may be mentioned that a far greater number of observations were taken in 1907 than in 1906. It is desirable, therefore, in draw- THE WESTERN MACKEREL FISHERY. 279 ing a close comparison, to consider only such observations as are com- mon to the two years. These are furnished by the analyses of plankton samples taken at the mid-Channel and Bristol Channel stations (Stats. E. 5 and E. 6) during the May cruises of the International Plankton Investigations. By the same method of comparison as adopted for other similar cases (see page 272) a curve was formed, showing the fluctuation of the principal zooplankton forming mackerel food. This curve (Fig. 1) PLANKTON MACKEREL VALUES CWTS. 1200 400,000 1000 350,000 800 300,000 600 250,000 400 200,000 200 150,000 roe 1904 1905 1906 aoe ee Fic. 1.—Curves showing, for the month of May, fluctuations in the quantities of mackerel landed, and of zooplankton observed at Stations E. 5 and E. 6. Zooplankton : mean between Stations E. 5 and E. 6 for May—Dotted line. Mackerel landed during May—Continuous line. shows the results of a mean between the analyses of the samples taken in surface hauls at the two stations, the following species only being taken into consideration: Acartia clausi, Calanus finmarchi- cus, Centropages typicus, Paracalanus parvus, and Pseudocalanus elon- gatus. 280 PLANKTON STUDIES IN RELATION TO TABLE SHOWING FLUCTUATION OF PRINCIPAL ZOOPLANKTON AT STATIONS E. 5 AND E. 6. May Cruises. YEARS 1903-7 INcLUSIVE. SURFACE HAULS ONLY. FROM THE INTERNATIONAL BULLETINS. The first column shows the comparative value sign, the second the adopted numerical value. 1903 1904 1905 1906 1907 || —— _-_—_,, || | ——. iS 55 6|(/ER 5E Clk 5 Bu Giz 5 w Glu 5 Ee 6 mM | Species. Acartia clausi |= eee tool Ste 100/} r | —| + /10}'rr]}/—|r!- | ¢ |100} cc |500 Calanus finmarchicus| e |100} ¢ |100) ce [500| cc |500)| ce |500) c |100) + | 10/rr} — || ce |500} e |100 Centropages typicus || + |10} — | — || r | — | +] 10|/ce/500/rr| — || — | — | —| — jj € |100| e {100 Paracalanus parvus es Meee | omeete EAUTE |100)| ¢ /L00) ec [500] + | 10} rr} — || + /10]-r | - Pseudocalanus ce |100| ¢ |100)| ¢ |100) ce |500)! c |100) ec |500)| ¢ 100) rr| — |} cc |500) + | 10 Blongabusl| | | Total num. value. 210 300 100! S210 1200 eto ns 120 0 1210-7205 Mean value. ; 255 955 1155 60 960 In order to form a wider comparison the results obtained from all the May cruises since the commencement of the International Investiga- tions in 1903 have been ineluded in the present curve. When compared with the mackerel landings for May as provided by the official statistics, it will be seen that the correlation between fluc- tuation of zooplankton and that of the fishery is very marked. This would tend to support the suggestion that when zooplankton is in abundance on the fishing grounds mackerel are numerous. As already mentioned many more plankton observations were taken during May, 1907, than in the same month of 1906, and as such were actually derived from the fishing area, west and south-west of Scilly (see Samples Nos. 52-55, Table II), they are of value, tending as they do wholly to support the evidence already cited. At every posi- tion within the fishing area the samples taken during a ten-minute sur- face haul were bulky, being composed for the greater part of two or three species of Copepods, viz. Acartia clausi, Calanus finmarchicus, and Pseudocalanus elongatus, the two latter more particularly, to the almost complete exclusion of other organisms. At one position west of Scilly (8. 52, Table IV), a ten-minute surface tow-netting more than half filled a sample jar of capacity approximately 300 cc. with these two species, in comparatively even proportion. In connection with this fact it may be mentioned that a steam drifter fishing ten miles west of this position on the same night (May 16, 17) landed four lasts of fish at Newlyn the next morning. It is perhaps unnecessary to cite further instances of a similar character. The Food and Plankton Tables and Fluctuation Curve THE WESTERN MACKEREL FISHERY. 281 speak for themselves in support of the theory that the quantity of zooplankton occurring on the fishing grounds materially affects the fishing ; the more food the more fish, and vice versa. Before leaving the consideration of the present matter, it is desirable to draw attention to the relation of phytoplankton to zooplankton during May, for the years 1903-7 inclusive. This can best be done by an examination of a curve showing the fluctuation of phytoplank- ton at the same stations and formed by the same method (Fig. 2). PLANKTON MACKEREL. VALUES cwTs. 600 400,000 500 350,000 400} 500,000 300 250,000 200 | 200,000 150,000 0 100,000 1903 ; 1904 1905 1906 1907 Fic. 2.—Curves showing, for the month of May, fluctuations in the quantities of mackerel landed and of phytoplankton observed at Stations E. 5, and KE. 6. Phytoplankton : mean between Stations EH. 5 and E. 6 for May—Dotted line. Mackerel landed during May—Continuous line. In the present example, however, it was found necessary to take every species of phytoplankton into consideration. In this it will be seen there appears to be almost a direct inversion of the zooplankton curve. There is an exception, however, in 1903, in which year plankton generally is low. We have seen that there appears to exist a marked correlation between fluctuation of zooplankton and that of the fishery. It will be admitted that the fluctuation of zooplankton need not necessarily entail 282 PLANKTON STUDIES IN RELATION TO a diametrically opposite fluctuation of phytoplankton, but we shall not here attempt to discuss the causes which promote paucity or abundance of phytoplankton. But little is known at present of the food of Copepods, and the inversion of the phytoplankton curve in comparison with that of zooplankton cannot be offered in any way as evidence that Diatoms, Peridiniales, and other comparatively large protophyta taken in tow-nettings are the food of Copepods. Therefore the paucity of phyto- plankton correlating to a large extent with the abundance of mackerel (Fig. 2) need not at present be considered as other than additional evidence to show that where zooplankton is in excess of phyto- plankton mackerel are more numerous—the subject of a former paragraph. Briefly now to summarize the results of the present investigations. The following considerations are submitted as forming the principal points of correlation between the plankton and mackerel during 1906 and 1907. (1) That during the three months forming the more important part of the spring mackerel fishing in the west part of the English Channel and Bristol Channel, viz. April, May, and June, mackerel appear to feed for the greater part on plankton. Gi) That the plankton organisms observed in the stomach contents of mackerel are also to be found in tow-nettings taken on the same position from whence the fish are derived. Further, that in a majority of cases, the relative quantities or proportions of such species are also common to both tow-nettings and stomach samples. (iii) That in April of the two years under present consideration, where zooplankton was in excess of phytoplankton mackerel were more numerous. (iv) That the abundance or paucity of zooplankton during a certain number of years (1903-7) appears to be correlated with the greater or less abundance of mackerel. III. THE “START” MACKEREL FISHERY. I. GENERAL CONDITIONS IN 1907. From the reports of fishermen at Plymouth and Newlyn, together with information derived from a fish salesman agent at Boulogne, it appeared that from the end of December, 1906, and throughout January, February, and the greater part of March, a regular and profitable trawl fishery for mackerel was carried on in an area of 20 to 40 miles $.8.W. to S.E. of Start Point. THE WESTERN MACKEREL FISHERY. 283 Cligny, in a paper entitled “ Les prétendues migrations du maquer- eau,” has pointed out that the existence of mackerel congregated in dense shoals on the bottom in this particular area, was first brought to light during the winter of 1901, and that since that time a regular trawling industry for mackerel by means of a specially designed trawl has been carried on by the Boulogne fishermen, in the early spring. In regard to this fishery, it has been stated by many fishermen at Plymouth that the best catches are made during the daytime, night trawling being often entirely unproductive. From a consideration of this fact, the fishermen at first were of the opinion that the mackerel rose to the surface at night, and a certain number of boats shot drift-nets in the area where it was known that successful trawling during the day had been carried out. In every instance, however, the catches made at the surface were very light, and the practice was soon abandoned owing to the risk of damage to nets. Toward the end of March, 1907, a Plymouth steam trawler, the Condor, was furnished with a special mackerel trawl, constructed in France; but losing this net on her first shot on the mackerel ground, an ordinary otter trawl was employed, with the result that a catch of nearly eight thousand mackerel was made, fish measuring 12} to 14 in. in length. A Boulogne fisherman, who was superintending this fishing, expressed an opinion that had the trawl been a regular mackerel trawl, and the speed capability of the vessel greater, a far larger catch would have been made. This fishing was carried out, on a position roughly 25 miles S.W. of Start, on the 24th of March. Five days later a Brixham smack landed nine mackerel caught amongst other fish 20 miles S.E. of Start. From information received from Boulogne* it would appear that in 1907, throughout January, February, and the earlier part of March, the French trawling fleet, numbering nearly thirty vessels, were landing regular catches of sixty thousand down. During the third week of March, however, the catches rapidly decreased, until at the end of the month scarcely ten per cent of the former catches were landed, and the fishery was therefore discontinued. Cligny, in the paper mentioned above, remarks on the close shoaling within certain limited areas on the ground in question, and this condi- tion has been further evidenced during 1907 by statements made by the Boulogne fisherman in charge of the Condor’s operations, who mentioned that of two vessels trawling within half a mile of each other, on a parallel course, the one would often obtain a large catch, whilst * A series of telegrams giving daily market reports, for the use of which the writer is indebted to Mr. R. H. Palmer. 284 PLANKTON STUDIES IN RELATION TO the other would fish lightly. The same fisherman, moreover, stated that he considered the shoals to lie parallel with the shore line. [ Note.—Amongst the fishing community at Plymouth and Newlyn a considerable diversity of opinion at one time existed in regard to the form and construction of the mackerel trawl. It may, therefore, be desirable to state that the writer was informed by Mr. Chant, the owner of the Condor, that the following details of construction, present in the net which was lost, constitute the essential points in which the mackerel trawl differs from an ordinary otter trawl. Not being in a position to show the actual specifications of the trawl in question, Mr. Chant stated that the otter boards were heavier, the length of the foot rope was 92 feet (less than that of an ordinary otter trawl, which is usually 120 to 130 feet), and that the cod end was longer and bred of a finer mesh, viz. one inch. These points alone, he explained, constituted the difference in construction. The main point of the successful manipulation of the trawl, he stated, appeared to lie in the fact that, when trawling is proceeding at the pace of three miles an hour, the length of hawser employed should be five times the depth of the water. With this length of hawser, he explained, together with the extra weight of the otter boards, there is no chance of the trawl leaving the ground, although it does not work so heavily as an ordinary trawl would, at the usual pace of two miles an hour. Mr. Chant further stated that the mackerel taken by the Condor were caught in an ordinary otter trawl, the cod end of which had been backed with netting of a finer mesh. ] Il. THE PHYSICAL AND BIOLOGICAL CONDITIONS OBSERVED ON THE START MACKEREL GROUND. As a result of a series of observations taken from the Ozthona at two positions on the mackerel trawling ground on March 27th, 1907, the following is a summary of the chief physical and biological conditions then observed within the area :— First Position—15 miles $.W. from Start Point. Depth, 38 fathoms. Condition of bottom, fine sand. Temperatures: surface, 9:25”. 11 fathoms, 8°35’. 22 fathoms, 8°26’. Bottom, 38 fathoms, 8°3°. THE WESTERN MACKEREL FISHERY. 285 Second Position.—21 miles 8. x W. 2 W. of Start. Depth, 39 fathoms. Condition of bottom, coarse sand, fine gravel. Temperatures : surface, 9°45°, 16 fathoms, 8°65’. Bottom, 39 fathoms, 8°65°. General condition of plankton* taken by coarse and fine nets :— Bottom (39 fathoms). Four species of Copepods, chiefly Zemora longi- cornis, not abundant; few other metazoa, including Otkopleura dioica, rare. Phytoplankton in excess of zooplankton, composed largely of diatoms, Lauderia borealis and Chaetoceras denswm, both common. Fourteen other species of diatoms observed. Surface plankton, similar in every respect to the bottom samples but slighter in bulk. Petersen trawl samples from surface, midwater and bottom were composed largely of several species of amphipods: Aphereusa bispinosa, very abundant, Lathyporeia pelagica, rare, Huthemisto gracillipes, rare, Monoculodes sp., rare, Paratylus vedlomensis, rare, Stenothoé marina, rare, Urothoe elegans, rare, etc. Schizopods, viz. Anchialus agilis, rare, Gastrosaccus spinifer, rare, Mysidopsis angusta, rare, and M. gibbosa, very rare. A fair number of post-larval fish were also taken, including Clupea harengus, plentiful, Plewronectes microcephalus, common, Solea variegata, rare, ete. An unsuccessful attempt was made to obtain mackerel in the otter trawl. The following species, however, were taken after a two hours’ haul: Arnoglossus laterna and A. megastoma, Callionymus lyra, Gadus minutus, G. luscus, and G. merlangus, Gobius quadrimaculatus, Plewronectes platessa, Raia blanda, Rhombus laevis, Solea variegata, and S. lascaris, Trachinus draco, Trigla cuculus, T. gurnardus, T. hirundo, and T, lineata, Zeus faber, together with several invertebrates. II. GENERAL CONDITIONS OBSERVED IN STOMACHS OF MACKEREL TRAWLED ON THE START GROUND. The contents of six stomachs were examined from the fish taken by the Condor on March 24th, 1907. A general determination based upon the six samples will be found in the Food and Plankton Tables (Table V), Sample No. 24. It is desirable, however, to describe the present material more particularly. In the six samples there appeared to be two distinct types of food, together with intermediate stages, in * See Plankton Tables, Sample No. 38. NEW SERIES.—VOL, VIII. No. 3. U 286 PLANKTON STUDIES IN RELATION TO which the one converged into the other, forming, so to speak, a mixed sample. In one stomach only there occurred a pure zooplankton sample, consisting almost entirely of Temora longicornis; three other species of Copepods were observed in extreme scarcity, viz. Centropages typicus, Paracalanus parvus, Pseudocalanus elongatus, together with a few Caridid larve and Amphipod remains. This sample alone constituted the one extreme; the other, which may be considered as phytoplankton, was represented by three slight samples, which were composed mainly of a number of plankton diatoms (Lauderia borealis and Chaetoceras densum principally), together with a few bottom forms such as fihabdonema sp., forming with an indeterminable quantity of Phwocystis globosa a glutinous mass. Entangled in this material were observed also a few Zemora longicornis and the three other species of Copepods above mentioned, together with a large number of Oikoplewra dioica. In the case of the two mixed samples, two slightly different types of food were observed. In the one Zemora longicornis occurred fairly plenti- fully throughout the stomach contents, which otherwise were composed of the phytoplankton mass, as already described. In the second instance Temora longicornis formed an almost pure sample in a layer deposited above the phytoplankton. In connection with Ozkopleuwra dioica it is interesting to note the following points. It occurred in greater abun- dance in the stomach samples showing phytoplankton and mixed material than it did in the tow-nettings taken from the Oithona (see Table No. II, Sample No. 38). Secondly, it was not observed at all in the sample composed entirely of Zemora longicornis, and lastly in the mixed sample already referred to, where Zemora was deposited in a layer, it did not occur amongst the Copepod material, but was plentiful in the lower layer of phytoplankton. These points alone in connection with Otkopleura dioica appear to constitute the sole difference existing between the plankton samples and stomach material. CONCLUSION. It has been suggested by several previous authors* that the migra- tions of the mackerel are not so extensive as hitherto generally supposed. Cligny, in the paper already referred to, states that, as far as his observations extend, mackerel return year after year, at the close of the shoaling season, to certain confined areas not far * Allen, ‘Report on the Present State of Knowledge of the Habits and Migrations of Mackerel” (Scomber scomber), p. 26, M.B.A. Journal, vol. v. (N.S.). Garstang, ‘‘On the Variation Races and Migrations of the Mackerel” (Scomber scomber), p. 286, ibid. Cligny, Les prétendues migrations du Maquereau. THE WESTERN MACKEREL FISHERY. 287 removed from the spawning grounds. At present only a few of these winter quarters are known to fishermen. Unless, therefore, certain other areas in the Channel exhibiting physical features common to the Start ground were thoroughly investigated, any attempt to suggest a reason for the preference of the fish for such particular spots would be based upon insufficient evidence. In reviewing the foregoing observations upon the physical and biological conditions of the Start ground toward the close of the ‘trawling season, it is desirable to draw attention to the following points: (1) that these bottom shoaling fish appeared to be feeding largely upon plankton; (2) that the plankton species observed in the stomach contents were common to the tow-nettings taken within the fishing area; (3) that Ovkoplewra dioica occurred in great abundance in stomach contents composed largely of phytoplankton, but in those containing a considerable quantity of zooplankton it was scarce, and further that, under the former circumstance, it was far more plentiful than in the tow-nettings taken within the fishing area; (4) that the tow-nettings taken on the bottom showed a greater bulk of material than those from the surface. IV. FISHERMEN’S “SIGNS.” AMONGST the west and east country fishermen there are gener- ally recognized certain distinctive types of water in which mackerel are said to occur more or less abundantly. According to the men’s statements, the colour and appearance of the water, its smell, and possibly upon occasion the presence of certain marine birds, comprise the only indications by which the drifter is guided in making choice of his position. That these “signs,” as they are termed, are the outcome of ex- perience there can be no question, and the greater or less capability for interpreting them makes a better or worse fisherman. An instance occurred on one occasion when I was at Mevagissey, when one fisherman shot his nets a few miles to the landward of the rest of the pilchard fleet and secured a top catch; when questioned as to his reasons for doing so he explained that the signs at that particular position were altogether better than any that he had seen the previous night farther out. At other times I have heard a fisherman state that he could not hope for even a fair catch, as the class of water was entirely unsuitable, and on hauling nets this surmise has been found correct in every instance. Before proceeding to treat the matter in detail it will be well to 288 PLANKTON STUDIES IN RELATION TO ' summarize the result of systematic inquiry made amongst the fisher- men in regard to their views upon the subject, and to detail the different characteristics of the various types of water as described by the fishermen themselves. “Stinking Water” is of a dull leaden colour even in bright sunlight, so dense that a man looking over the side of a sailing drifter cannot. see down to the keel. It possesses, according to the fishermen, a distinctly noxious smell, which has been described as similar to that. of decaying seaweed. The men are agreed that mackerel are not to be found in such water; but one informant stated that scad or horse mackerel are often present in fair-sized shoals. “Grey Water” is somewhat similar to the foregoing, but does not possess an unpleasant smell. Mackerel are never numerous in such water. “ Blue” and “ Green Water” are both suitable for good shoals of fish. They differ, according to the fishermen, merely as regards colour. Both are so clear that the keel of the vessel can be seen distinctly. Both varieties are the usual types of water found in the western area in the early part of the season, right up to the first or second week in May. The fishermen are agreed in considering either type sufficiently promising to allow of fishing with some prospect of a fair catch. “ Yellow Water” is considered to be the best of any. This, according to the statement of many fishermen, exhibits the following character- istics. It seldom appears before the beginning of April, and more often not until the last week of that month. It is of a distinctly yellow tint, and rather dense when viewed either in sunlight or under a dull sky; often it appears in patches of greater or less extent. In certain years the sea west of Scilly has been almost entirely of this type of water. It appears, according to certain statements, to be teeming with “minute animal life.” The fishermen agree in stating that the largest catches are always made in such water, and that it is not usual for an unproductive shot to be made, although, by the state- ment of several fishermen interrogated upon the point, it would appear that light catches are occasionally made in the best type of yellow water. Certain fishermen consider that the colour of the water is not due to the excreta of mackerel, but to the general colour of the “swarms of water fleas,” whilst others on account of its density contend that it is coloured by excrement of mackerel. : Other “ signs.’—Apart from the characteristic of smell invariably associated with so-called ‘stinking water,” the generality of fishermen are agreed that a shoal of drift fish may be detected by their smell. This is more strongly pronounced in the case of pilchards, but, with THE WESTERN MACKEREL FISHERY. 289 mackerel shoaling densely, the fishermen state that there is no mis- taking it. An oily appearance at the surface of the water generally occurring in “splats,” ie. patches, is also said to be a sure indication of drift fish. A milky appearance of the surface generally occurring in inshore waters, where there is no addition of china clay to the water, is asso- ciated by the fishermen with shoals of small mackerel, the milky appearance being due, it is stated, to excrement. “Signs ” of shoaling fish offered by the presence of sea-birds preying upon them occur more frequently, according to the fishermen’s state- ment, in inshore waters, and the point is one which has already been described by previous writers, and need not therefore be discussed here. COMPARISON OF “SIGNS” OFFERED BY DIFFERENT TYPES OF WATER WITH THE CONDITION OF PLANKTON OCCURRING IN SUCH WATER. In order to endeavour to ascertain to what extent these colour “sions” are produced by plankton conditions, a number of plankton samples were taken for me in 1906-7 by fishermen, and labelled with reference to the particular type of water from which they were derived. “ Stinking Water.’-—Sample No. 39, Plankton Tables, was taken by myself on April 10th, 1907, in an area of water termed by the fisher- men. “stinking,” which, it was stated, extended from the Lizard to Land’s End in a zone of varying width about ten miles or more from the shore. At the particular position at which it was taken, 6 miles N.W. x W. of Lizard, the fishermen were agreed in stating that the water was a fair sample of the “stinking” type, and that it would be useless to shoot in it. The colour and characteristics generally were in accordance with the description already given; but although the fisher- men were agreed in saying that there was an obnoxious smell, I was unable myself to detect it. The analysis of the sample showed (by the method of comparison described in a former section) a moderate pre- ponderance of phytoplankton over zooplankton, but the total bulk of the sample was comparatively small. As will be seen on reference to the Plankton Tables, the phytoplankton was mainly composed of diatoms, of which Chaetoceras boreale and C. densum were both common. Phaeocystis globosa appeared to be rare. The zooplankton comprised three Copepods, ) +|+]+ Id TW ‘A ‘O ; : OBALB] * BAO YS "1091099749 4 [Og ‘votorp vaine{doxIQ "DIDIVUN T, "Wa, qT ‘VSI9AO.AJOL VUTORULT * OBAIB[ VLRITOURIGT[[OWe'T * aBvAley epodojeysey) * BULDBUUTT aUOT]O “pos OTT * adeys edoresay : : : ava07 ‘qolttrT ‘snrpourioyur wopog Iq ‘Nyonog sauvyddyorny ; * snide yy UdAOT ‘TUURUIP.ON oupeagy UBULION ‘sodt[[Iovis oystULEYyNA ‘ avArey etpadti4ip9 * BAIR] VBPTPLAeD SIBY °C ‘4D “TeaoTD vsnaoydy SIS “OQ “1D ‘SI[Se stperyouy “040499 DIIDISNAD *SIULOOIS UOT BLOW, *‘yooog ‘snjesuoja suuepeoopnosg TIMI “AO ‘Stustooraatq etaquodeieg ‘sne[) ‘snared snueproereg . * ‘sne]d “sttrurs paleg ‘eroyreunyd qsen) “euvu BuOYyyIO Apeig ‘voryweyye v[pojesosorpy yooog ‘susan, erIplajeyy yooog ‘sadravyo svisT ‘eur ‘suoutqnoe adazoyngy ‘qquy ‘snorpsur snavofsi09 wXory ‘snord4y sasedoryueg Apeig ‘eyearyoad vrorpurg uuny) ‘snonporemuy suuepeg ‘duay, "Y ‘tuosseyjeg vilooopemouy (sol) “Isne[p eyo “‘mpodadoo na0nIsSnL) PLANKTON STUDIES IN RELATION TO 296 far Spee el ee ll ee el laa eal all es lea raj}]—|-—|-|+]/+]o0]9o0)o0]+ d0]| - : : * “wBID | ‘st[valoq eliapney eile Ei Sa lees 0 eos aI ee Cs Tce =f] = frat = |=) 10) == -||- : * “Treg, ‘aaSt[Ja4s snostpo[eAH Si eallibe Se ooceh | ee Na | eea |e ee || ~|—jJaafaa] + jaa} — | - [aa] - —||° : : (1388) Bploory BIpleumMes alee te ah hee RE et eee A PP ae he a ra|—|— |=) -— |= |a@a] —|-—1 = = lee ; : ‘Squy ‘snoetpoz vidureong a | eal a = - fa) —|— = 0 ea - c : * (489A) WeaqyoL mnypAqi u 25 ge eal leah ee hee St Nf | ff Se eng + lls : : : ‘DqyA ‘snyeIpel = a = a i fe SS cS ava = — ||: : : * -“Squgq ‘stput supnoo eae alle a rol eee [oc = tal - Slee c : : * ysnor) ‘RI canoe a 2 Seen (ate - - = ety| me |e + || ° : Bq ‘snolI}W9dX9 SNOSTPOUTOSOD ee Ss oe ee Bee ey eee “= = - I i : neste H ‘x1aysiy LSSRNEGNE(C) Sih Aas Sea rege ees hs Nae ee | | Nene SS a ih ‘ : ew) *sa.1a} se Pee eee ty al ea ally -|- i stl er Ud : : : * dAaiQ ‘IgnyoS = lene Sayer els = |e all geal) eee a rajxr}/+}/+)/o]/o]/o0]/o0}+)9 a1) : . : * ada[Q ‘umsuep ea wR a EES Shee a ce a ee eo me Sp) ee allen eve ersten |erirall teth ae q : aaa[Q ‘suatdioap =n = - = = Id : : * dada[Q ‘apiqap S| eal = Slh= 4 SS eS a Sal Sis ee ea = SS ae le a SB = + | : : : aAaTO “wnolmep Saba ee = = - = | = | =f) = | =] ara}ra| = - : : * ayseg ‘uIngn[oA mod Ee eR | RE pene feel | eae rh le | hee SS) = | ae eer tae ey Se | at ate S : : 99nYOS *w1n4.109 09 op era SS, = = - Moh te) el ate etait fi eal - : : ‘req ‘a[vatoq setaa0jovyO, Shes = RoE eee LSS Pa eas ee es ean Fea fee Sha alee Deets Loale Vex cL ade - ; : ‘Belg TUWOSIeg BVUI[Ne}e.1EA Sos male = - - -- I : * "Treg ‘sisuatiq our erydyuppig = ee, pe ae 2 2 GE ip eal rs Se Se liacadl 2 : t “eur ‘vxopured elielloeg et ee fee alee = Se - - —|a|- - : + saqyseg ‘voruodef e[jauoleysy €9/| 69) 19 09|69|89/ 149/99 |¢¢| bo |S sG| TS 09 | GF SP | LD | 9b Sb| bP 8 | SP I Ob | 6E 8€ | ON aidureg “anaoDULojnET *% * * % * * *% * * * * &|3|s Sy |e feet lee Ron eeepc ent eee S/S /SlelS| alain] ale = B| 8 | 8 B/B/B/F#l|slelelelels|s|s B/H|S|BiB/BIBIE lB 5 alata] jal2lal"|Ple(Efele(P/Pls| Welz (Ze (eieigie| le 2| |e Ged ea Ta a SS al re TI dl ovale aise Slo le) a/2]e me | | x Zl2e|4 St culate eae leer @ elalai=l|*l/e)/*!| 419] % = 2} alo Sane les Sree elias S| cya set lesta pean Mheen Se | testes ws “uaTINE “a “D Aq poyerT00 aydures fey ||Rey || sae almanacs Salle Ieee ie ee) o | 3 a RPS lol eIls |e = seylusis y Suy} Ysueyse UY— ALON Bb) e S\3| 8 sh) oracle Z Bleleleialeleisiale 2 Plas: mile | & Sale Sp lip e eet | eas tsk |g aS 2 iS) &|o6 i] area ey Na FS 2 Rn ei ore | Bo ete 5 Es = 5 . . . * aa| . . . . . se Z bg ee | re) ‘eh : : | Baler ape leh 6 seks Biles Balke o1| 9% |\te\ec|1¢|st|at|at|at|zt|at|or|or| | egleciarter arlene ot} jaz | | anae AVN T1udy HOUVIA ‘L061 ‘SGNQOUD THYAMOVW NO CALOXTION NOLANVId— II ON #14 297 THE WESTERN MACKEREL FISHERY. 00 +++ H id 00/900 at — SOG + | a Ij} a +] + +/+ Tl) id + |+ Ijd +] + Oy ict Get — |ia =| En aq} -+ Id} 1 = eed ne dl Idj/i@i Ii) = Oo 09/00/ 2 Oe |= | Id Id a + % = = , = * ‘Taya, “esoqo|S stysAo00vyg * sz2qrutog ‘stprita viavydsoe yy (‘sqyq) tunqnoeds snuvydo4ysiq Dqyy “Bpuqy vpoodzorq “puajao wyhiydojoug ‘Squg ‘ SUBOTUL WINI4WI00L01, J : BIO ‘UIE}g ‘AsO ‘uanprted ‘yeyonog ‘uingeAo ‘Treg ‘unssaidep ‘UB SUMOTUOD WNTUTpItag ‘ulayg ‘vurmmeasdjod xepneAuoy ysieg ‘ernorjuey stpesdoypdiq luayoyur A (‘uyor'T pure dep) vyepungor (‘sqyq) eynov sts{ydourq . 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TIUW ‘A 'O ‘stuioo1su0] Boag, *‘yooog ‘snjrsuojs snuejeoopnesg : ‘sne[Q ‘snared snurleoered “sne[O) ‘SITTUUIS “IQSATY “RULU BUOY YO ‘yooog ‘sueonyt BIpzeyT ‘yoaog ‘sadrar[o seis] : (eur) stoayrynoe odioyng : ‘qquy ‘snorsue snovof109 + goXoryy ‘snord4y sadedosqzuag : Apeag “eyeuryoed soxpuep > wunsy ‘snoryorruiuy snuelep ‘q[dwoy, ‘tuo0si0}4eq e1s00/eWOUy ; * rqsety ‘Isne[O BIyBoy ‘ppodedoy “naonpsni) ‘yoorry “eorpurposjay stieydowoy, ‘urery pue “Longy vyeqoundiq vyIOeg : OBAIB] BPI[OULVY "sada A 7 x Peas PLANKTON STUDIES IN RELATION TO ¥ 300. os (‘YSt OGL = perpuny) Ble O8) = 11-1106) = I jet sft lH l=l=l— hfe oe) =t=) |---| =1=|—}logtogi— i -l— W=1 2) -)-}=1-|= « Sporpuny ,, UL WAL} ST JO “ON ~ =f=f-}-|-]-]-l-|-]a +/-|-|-|-]-]-]-]o}]4]-|- 99/9000] 0 joo) 0) 4] 4 |}+ 00] 90 | xa} — -|- —|o}—|-|-]o]}-|| : * Tayaayog esoqols Ps syyshooanyg Ayaryo woyyuedoyhyg Itaja}—jaraja joa —la}a +/U}d}ajaitaoj+jofjofojal ff—jajal}+)/+}+]+]o}o jooj+)a}+ O}+]) |itajt+}+}o}—-joj+]} - : [Od Potorp vanatdoxto, T}ait]+}a}+jeaja}a}a]t +/o}+)o]/2/o}+]oo)2}+]+]a Tajt+{t+}i}+)o}o}o/+ia2]o}+}—- ite lee d}al/+jojo}—jo]] - wrey pure fond vyeyoundiq wq15eg Tj jlU o)—|— lta —jraj) 2 Lt) +i)+i+)2)0)2)0]/0)/4+\r12 ae pay) eee ar) ariel | cel ee I{d L JL UCU I Ita} —}—]|| * avo07 —}-/|-|-|-]a}-j-|-|- +|4a) tjoa}—|—|—|+])a}+]—-|- —|fa}—|+)/+]/a]—Jal}a jaaj—laa— -|- —|-|-|-|aaj—|-]| ° * [QW “A °O Studoo1s uo] viowey, +/9]900/+|/1]00,0}+]0 +/9|/+jooj+/o/+]+/+/+]o]—- Lyi bit] +i +)+{+)+}+]9 joo) — a0 (Gs Ttaj+)+ja}+}+]} ° * yooog snqesuoja snurlroopuesg +)+]+,09)+/1.4)/00 +/+) + +/O ft +)+)+)+) 2) a} a}+]— +{+/+]4/+)+]+/+/+)0]+)oojr2 xa 1{—|+|+ltajcaj+]] ° : ‘sne[Q snaied snurrroeieg —|tqja/+/a}—-jala}afa Td) —|raj+]a}+)a}—|—laal ar] — t}+]/+/+}o}o]o}+iaaaja}a}— —|- —|fa)a}a}—|a|rall - ‘ : yooog SuUdONT RIPLII +]taj/rja}+}ojoo—|—la TX] U [Lat ala ala afar a} + | — fatal a | — —€ ot} o}+/ a4] a)+/4\aa}a jada Id) a —|—|aa)— jaa) —|— aakoaryy snord £4 sasedo1yuec 9/9 9990909) + \00900/00/00 +) +)+]9 )99)9 00) +)0)0)90) 2 eel eae ar| OO) eater anlt cl ar yar FLY + i+} O}+)+y} ° : uuny) SHOTYoIeWUYy snuvpeg L}CATA) Ctra) Of a jrazajca| |f|+)0) a jaaajra) alca)—| a] +) a II+/+)/o}olofojoloj+i[+{a}+} faajca flxaj—|—laaj—|-|-|] : : IqSeTt) ISNLID VIyLLOW —sawody ASGL9S PAGE DE SAESISL SE) | TES ESBS TLIAZ/GSOLE99ZIbSES, |89SS TSETSI/AT/9T\GT PT 4901 99| 6 8\4 9|99| 9b | 3 |p9\8|| ‘ON erduueg d|$|d/S|d|dj8|djS/d d|djd}d|8|d}d|8|8/d/djd 8|d|dj}d/dj/d|d|d|d/S/d|8/d dj} d d|$|djdj d}/S|d ‘e[dures uoyyurlq@=q ‘wormoyg=g S/S/S/R Si FiS/Slsis SlelsiSiS|F(F/S/e| ails SSIS Sle |S/SlalS]S la] ¥ e\e Gl eeelteiteriGe ecules S/SISIBIBISIBIBIEIE| |SlFlflslBltl[elBlS|BIBIE| WBIBIs|Plgle lslelslelslzial jigia| |glElBlBigi2l2 4) mo) colala[Slolmlala| |S/B)| ol ale 2 |ro|c|co|clo| |ile| (Z| a] mo|rolcolcoloololalal| |islal jele|e|e|e| |x y sla se Sisal (Sislelaacle ee Zio] Fi Fis ielZ See eieieizer Wels lelalalalslols BIA) S)x|x |B |S) Sele] |B Pox |k/o]8 |Z lejo | 215 2/ei84lS|4(4/4)4)4)4/2/2 1 (218) |Elalalclzi2 i= Bl |x| m2) mex |x lala Ble |- laljml: ja |Fl t) 4/3 Siecle neal Us Peace endl coal il wl oe tad ce S41 818\. 2 Siele ele SISISIS18) Sis}. |alziSlaialalolalo saalts| yee "93104 219) | eae} | a|= BIE) lg 4 3 i a is 2 |O |] 9 }o o o = = 5 | | aIaM SoTdures e1eyA SUOIZISOg wlo/2/21. |zl lols “|g e ye VE a Velen eel ee le Ble lel. | EO lo 2.) 8.) )o x = g = (ale aS hs ols < 2.) o.) 2 SY |S | Be = Casals |B & enon Pe ietleale cheat 3 5 : ° % |G |. | = @ | 5 Bye. N 2 elt|ut|etiet]8|4|4{/¢]9\| |selerlerjstloristlor| lorlor| |r| Bebalee waa earotes es tancercrl velet|| |eepriprletietletlet] - -° + sara | eee | Hes tee eel | anor AVN T1ady HOUV]L AUV ANALY : : : HINO] ‘9061 ‘VaUV NUMISHM “ATAVL NOLMNVWId GNV GOOdA—III ‘ON WIAVL AND PLANKTON TABLE, WESTERN AREA, 1907. JUNE May | —< som THE WESTERN MACKEREL FISHERY. 301 m ; ; ee ; (Si {= 0° axqmeyr go -g ur eg mia sat Suepi 1S Se a uATMeN Jo"GS ugg | FY [Bx Sl] HoH ie | os |° FomIoM gS moe | A IPSS a+ hat | tt =e doysig ovm'S MMOs | A ISR SRat+retio 44 ; z F Qo ° ° 9 FOMIOMSM Us| MISI Sei geet 1 18 fos) a | * doysig JO "M"g§ “Ur GF | ~m Serre leech ont | I~ eer = : D if el |S (TOM JOUR MUL OR | 2 |O ES. we Po oa bt eG FOMIO MSM UNDA |SriSkpo; Fey 4 & |° * hymen Jo "sx "Mg “at GF | a S Bt Ee Sein Lh IS & |° ‘gjoyssnowjo‘g'moe | A, (BR SPHohG 4, Tt Tair Se eoussnoW JO"M'S M09] m |SOtOo+tHS+et+1 18 P| 2 efoyssnoy JO“M "SG “WLOg | w® Sputpo Sut 1) oes Sarat WOM IMS TE] my |S+S++9HHH 1 oF nl: Coystel JO “A “NM “UI ST A 8 COOH ORHHO ipl Sai Ba a 1°" 3219 Alia So OU Sc ee at) [a Pg eM erl fom ee eer i sree ae sy "M9S'OX N $'6r | A PB 4++ HH SH+4 | iw Ss saws) o |Se+Sit+S+He+t+s 1 ar “MOPLX Maren a0 | oe 2 aa S er 7 2) Wr aigox Neer? | aS erSp esSive h t it = ee SU E> laermaeghuais eal ee 5 “oe me | A letor og tite Vi nan (=) = ATogjo-m's mos | a |oxgiaesglt+it 19 | S Lr doysig jo"mmop | JSxSrireSieri 1S Sr WOMIOMS uae | on /SxSrxSrery 11 Ss = efoyasnoyy Jo"gxmg urog | M |B+trv!i |1oory } a) Le ariel z i es x doug jomsmug|/ a |RESHeSiar 1 1a o doug josx'mmss| a |RESIRSiHt11 18 o doysig Jo"gx'Muss | A IQwe St eolrti ew 1d : * doystq jos: CIES pe ed = x PHOS OBesihsttii is a) eee ties A So rs) doysig Jo-M'S ass | mM PHS, S11 BI 1S a a|Bsury JO “M'"S'S§ “UW OF | M = Wel ees eee © rt - doysig Jo'NX'M ‘Woe | 2 8 EOS (RE OR teri et (ee Eras | ~ So = COWSITON RX Mg top) (Ry [Rg h Sot BOS etn 1 ES is 4 FOM JOM MOD | [sir ori+hi i+ 18 27 '{\e : doysig Jo"M ‘UL0g | M Se See Ones th lel is | 3 FOO MLO |B Sores ree TS Lr ; FIOM JO"M*S *ULOT | Ay Store ottts Sal So sdgussuoT jon wos | A |p OoKpOP E+E. C1 & sdiyssuoT JO"M EN WOT | A (Brox nt+o++H | ry ad THE WESTERN MACKEREL FISHERY. auoyskppay JO “M"S “UL OT qivqg JO'M EF "MX "Sg “UL TS (punory U0) 4124g Jo “g “UI gz == jaa pepe |e | ales See | Sete Se ey i yay) = S| Hayy) = —|+ Oo 0/00|/ +)00/ 2 a 3) — —{+ 4) = 9) d -—- ies | ela rebel Ii} — | — - a eo = SSS css SS a SS Sere he sai Agr Sethe || alo engl Se = pes heb |S Spa Spline Sa eee OIO2 |e |o— en | O10) a) ee Ass elf ce lft lf se 3) = T +100] 0 - Oo ;11/9090] 0 Jd A) +)-— |00/00/] a2 +)4 9) Af I I | i220) — I +) — 00] 0 1 OS Ter | 20 — |090/090)] 0 3) 00/90/00); 0 |090/00)/00/090/00/00 0 }990} 09 }00/00/09] 0 > ciel ick Pele |p ert facie} at ete cto eta eee ft te mee iar feo dee lence | ae TaD eT | fae) MM eens |e need | ad [eet let = i Vis al [et ge ey pete Pr Fact) Gl fc ted Up Tt =| 2 Deleon | Se eee Sf |e a el me ane ee ft (a ae facie |) acne Sol ies) let iiaen I}/+)/o;/+]/+/+/4]- GEISETAET OST GEL PSTIEST SST/ISTOSTIGST)| | SST/ALGTISIGSIPSLesl SZTISTOSISIT| | SITAIT| Sb |9TT SIT PIT TH lett S|S|SiSisSisisisisisis 8-98 18) S| 8 | Ss -s:}s4 sis Ge Ede). Bele ciudslas = Bi/s/FIPls|/Flsisis/Fle piPleils|BiB|E|B)B|8 BiPle ls /FPiFPlsig eis PIPE ELSIE BY e R Bae: B |} EL Sel PlZl SB) A/21elelal (2/2 gale lelelale/2] |e alelele/el2l2 ® F : GCE Nase Pe eye prec | ate 5 I 4 4 Bs ty | - = salts ae a5) alee Salers S nfo ee Sele ele 13] ZBle SS Se oe | SH. al S 2a eae etter Py) Slate | Si BiB el Bele S| Tle ei slelel= |S) alal fe) elo Si eis) sie g Hl >) ealy|/Bleo|/ele|/8\4/e 2 pea lelectra %|#ilo|2 Te eee lites steele al sere lings Sof peels eres dst ee dese | etl teateiee lass g¢|/Hl/o|s |] | & Blo |e s | & 6 |8 alse EL Sele Sl Slee sleigie] | sisi sleizlel zig)" (4) (eleieieie) |e) * S| (SielSlElS Sle lele/e lel | je elelaielgi gi |: S/R a} e|" | 5 Ft Sh |/oeeal) teil SI SP 2 5B 5 Sleeales lesion | ais B | p =e : fol fet fel Gasca fara s e ® Se epee eos ae eos Bee eB Sl) et 8 ® S| oO = co |e [teletjet|atlar|er{et|stlst| || | | og |2¢|22|98/9¢|0¢8| 91] + | 502 | os | e¢|s¢|2¢\%e|2t|at\et| 9 | 9 | | anor AVN mud y ‘LOGT ‘VEXW GUVZIT OL HINOWATG ‘ATAVL NOLMNVId GNV GOOd—A ~ < sH a TOY [e193 OU o- : Toe ecoaars stysfooavyg sperms ‘no quepdoydta * sniqos -oT[eyshayQy IO YSty Sunojx io ‘Rololp vine[dox1O : ‘ ‘mre pue ong ‘eyeyoundiq B41NVG $ "98007 : i ; ee Ut ‘dO ‘SIUIOOISUOT BLOW, g * *yoo0g ‘snqesuola snuepeoopnesg UUN+Y ‘snoItIVWUYy snUeyed * “Iqsaly ‘Isne[D ey1e0V ‘sawady : : * ‘ont ofdureg UoJyME[G=q “qorutojg=g “Udyv} OOM soTdues o10 A SUOTJISOg ; LLVG : ‘ HINO] ‘ON WIAVL @e~ Colanus finmarchicus coy ¢ ort) corr. Oo- Ooo Pseudocalanus elongatus, ditto. A Aae ZTemora longicornis ditte. | = Phaeocystis globosa ditto. left hand sign marks position in each instance. The s1gn O under plankton observahons = zooplankton in excess of phytoplankton. D= te reverse. The Figures above the signs denote the day of . the month. Figures below the signs denote tha number of mackere/ taken on the spot by the vessel which obtained the plankton sample. To face p, 302. ie y, q d { "7 W { Ppl) << ath el epreenn tepals asx) i Jy ay a Br a = ACH ® r ! 5 h { Tih Mena a Figures elo ~- age Melua dota, ea as + Yes Plate Ez, __ Journ. Mar. Biol. Assoc., Vol. VII. DISTRIBUTION or SPECIES CHART. JUNE 1906. Bec=- Calenus finmarchicus ce; .¢ orrjr ore. 1 O00 = Pseudocalanus elongatus, ditte. MA, = Timora longi cornis. ditto. BM me- Phacccysh’s gloposa. Ate. The left hand sign marks postition in each inshance The sign O under plankton observations only = zooplankton in excess of phytoplankton, B= she reverse. The Figures above the signs denote the day of the month. Figures below the signs denote the number | of mackere/ tke on the spot. by the vessel which | obtained the plankton sample. 2 anM4 | i o f oy Cs _ Of8 - JIT Jo¥ .s022eA slo “Ag Journ. Mar. Biol_Assoc. Vol. WI. : ___ Plate Xxr. DISTRIBUTION or SPECIES CHART. APRIL 1907 . @ee- Calanus finmarchicus cc jcor+; rarer. O0c= Preudocalanus elongatus dilte. Abs ~ Temora longicornis ditto. Bm@e- Pccocystis globosa ditto. The left hand sign marks pesttion in each inshance The sign OD under plankton observations only = zooplankton in excess of phytoplankton. Qe the The Figures above the signs denofe the day of the month. Figures below the signs denote the number of mackerel taken on the spot by the vessel which obtained the plankton sample. lo pote eteal ny r he 2 rrr ‘ 7 | el lien ieee ieee dees Seemann daeeiianaemer anand at a a * |] Ge « = Colamis fin ‘ cs |} OOo = Pseudocalanus elongatus. || Maa = Temora Slongicornis. | MM. = Phacocyshis globose. The left hand sign marks position in each imstanee. The sign Dunder plankton observations only = zooplankton in excess of phytoplankton. the reverse.) The Figures above the signs denote the day of the month Figures below he signs denote the number of mackere/ taken on the spot by the vessel which oblained the plankton sample. TOT ree i me ie re a peu Mid wast . \ ee ; hag ee % ec rs e a = 44 ie a anny a! aa Seria sca a ass a Wesco, fiamarchious ccs € ots ror er. Oo = Pseudocalanus elongatus. dilto. Aa-e Temora longicornis is. ditto. t tf [ = Phaeocystis globosa. ditto The left hand sign marks position in each instance. The stgn © under plankton observations only = zooplankton inexcess of phytoplankton. D= the reverse. The figures above the signs denote the day of the month. Figures below the signs denote the number of mackere/ taken on the spot by the vessel which obtained the plankton sample. _”hUS ee £ ff hee ed NE Oe a Sree Te | | { | eh attenipinie es eimae iee ishabeleinnlia at ical eo j i i bat at al t ‘2 ye | | pentane a | : i telson cael ; Lf i ( ORY f oa | re anne | x | / | in clean amiaamnedenee Le ee ee " ant | tee | | ; | | 4 { ; ' 8 Me ‘ @ ; . y | af @ 1 W aGee ” k i } mf es ri ' 4 . ti wt ¥ i do [ 303 ] On an Experiment in the Keeping of Salmon (Salmo salar) at the Plymouth Laboratory. By L. R. Crawshay, M.A., Assistant Director. With Pratt XXIV. For the past two and a half years (1906-8) some salmon, which were reared at the Endsleigh Fishery, have been kept under observa- tion in the aquarium of the Plymouth Laboratory. In sending these fish as smolts to the Laboratory, the Duke of Bedford wished more particularly to obtain information on two questions: firstly, the character of the food of the salmon during its sojourn in the sea, and secondly, the period of that sojourn interven- ing between the smolt and grilse stages. These and other points of interest that have arisen will be considered in order in giving a general account of the experiment. The smolts were brought from Endsleigh at two years old, and introduced into the aquarium in two lots (of twenty and thirty) on February 6th and March 1st, 1906, respectively. The actual weight and measurement were not taken at the time, but Mr. E. C. Rundle informs me he has ascertained that the average weight may be placed at 4-5 oz. and the average length at 8-10 inches. ‘The fish have been largely under the charge of Mr. A. J. Smith, and it is upon his detailed ~ notes that the present account is baséd. For the accommodation of the smolts, one of the aquarium tanks was emptied and brought into communication with the fresh-water supply, the water being led into the tank by means of a rubber hose- pipe, and kept running. The first twenty smolts were put into this tank on February 6th, 1906, and allowed to remain in the fresh water for two days. Trans- ference to sea-water was then effected very gradually, at a rate of inflow increasing from day to day, as follows :— _ NEW SERIES.—VOL. VIII. NO, 3. cs ae Sad 304 ON AN EXPERIMENT IN THE KEEPING OF SALMON February 8th, 11.45 a.m. Fresh water 1000 ce. per 15 seconds Sea ” ” 9 75 ” a 5) ths 1 0l30 asm: : : Density of water in tank 1:001 ; Fresh water 1000 cc. per 35 seconds “els Sea PB] ” ” 75 ” * ? 5» wkOth, 10:30-a.n- : é Density of water in tank 1:005 “4 Fresh water 1000 cc. per 47 seconds Seat ahs mn eet a ee * 3) 2th, 10.0 a.m: : ; Density of water in tank 1-016 Be Fresh water 1000 cc. per 60 seconds Sea ” ” 9 31 bP] »» 13th, 10.30 a.m. : ; Density of water in tank | Top 1-017 be Temp. 46° F. Bot.1°018 . ela Gh : : é : Density of water in tank 1:018 ‘ Fresh water shut off e Sea ws 1000 ce. per 31 seconds % Cis; aamloth : . Two more jets of sea water turned on. (One smolt died.) : g : : : : : > aetoth, 10:0°a.m, : 5 Density of water in tank 1.027 The water having now approximately reached the normal salinity of the water in the reservoirs, the supply was connected up with the general circulation, i.e. nine days after the transference began. The digestive tract of the smolt that died on the 15th was found to be quite empty. Feeding on the whole had been fairly good. On February 27th these nineteen smolts were removed to a larger tank. On March Ist the second lot of smolts, thirty in number, were brought from Endsleigh, and placed in fresh water in the tank now vacated by the others. Their transference to sea water was completed in about one-third of the time occupied for that of the preceding lot, and as follows :— March 5th : : Fresh water 1000 cc. per 18 seconds Sea ” ” ” 33 ” 9 eth 5 : : . Density of water in tank 1:007 Frost water 1000 cc. per 30 seconds Sea ” ” 3, 10 ” oy . tok ‘ : ; . Density of water in tank 1-015 Fresh water supply turned off Sea water 1000 cc. per 10 seconds se Nason be 4 é : . Density of water in tank 1:026 Supply connected up with general circulation. The transference of the second lot was therefore completed in three AT THE PLYMOUTH LABORATORY. 305 days. Before it began, one of the smolts jumped from the fresh-water _. tank, over the barrier, into the sea-water tank adjoining. It was left in sea water afterwards, and suffered no harm. The same thing happened to a second individual on the first night after the change began (March 5th). On March 10th this second lot of smolts was put into the large tank with the others. This tank, which now contained forty-nine smolts, was used throughout to accommodate the survivors as long as the salmon remained at the Laboratory. Its inside dimensions are 15°7 feet in length, 9 feet in width, and 44 feet in depth of water, giving a capacity of 621 cubic feet. It was fed by eight jets, giving a total normal inflow of about 385 ce. per second, and its position, partly screened from the direct light by a dark-coloured blind, is such that its lighting may be described as moderately low and constant. The back, the ends, and the floor of the tank are formed of slate, and all uprights or other portions of the framework are similarly dark in colour. Air was supplied entirely by the force of the water from the several jets striking the surface, which was sufficient to carry the fine air-bubbles nearly or quite to the bottom of the tank. Feeding.—The smolts were fed twice a day, and often three times. On the first day or two the food given them was broken biscuit and prepared fish and flesh foods previously soaked, of the same kind as that used at Endsleigh. This was then varied with raw bullock’s liver cut into small pieces, and the preference for this latter soon became so strong that the other was very shortly discarded altogether. This was the case with both lots of smolt. When the transference to sea water was about half completed, it was found that the common inter-tidal marine worms of the genus Nereis (NV. diversicolor) were taken very readily. About the time of the completion of the change a distinct loss of appetite was shown by several of the smolts for a few days. But, on the whole, feeding was fairly good during the interval, and this was particularly the case with the second lot, where the transference was brought about more rapidly. After the change to sea water, liver was taken with the same readiness as previously. Nereis was at times taken when liver was refused, but beyond this little preference was shown between the two. Experiments in feeding with marine animals other than Nereis gave entirely negative results. Among others, trials were made on several occasions with the following species :—* * It is to be regretted that herring was never tried. But the keeping of young herring alive for any length of time, even when they are obtainable, is a matter of very great difficulty. “+, ~ 306 ON AN EXPERIMENT IN THE KEEPING OF SALMON Living Shrimps (Crangon). » Prawns (Palaemon). » Pandalus annulicornis and P. brevirostris. Cut Squid (Loligo). 5, scallop (Pecten). Living Pollack (Gadus pollachius), about 2 inches long. » Gobies (Gobius minutus and G. ruthensparr?). Cut Plaice (Pleuronectes platessa). The salmon were seen by Dr. Allen to take hold of some of the shrimps, though afterwards releasing them, and to show a certain interest in some of the small fish. But there was no evidence of their having swallowed any of these objects of food, and the only conclusion to be drawn is that they entirely refused them. Two of the smolts were kept for some time in a separate tank with two bass as companions, the only food offered them being shrimps, prawns, and gobies. Although the latter experiment was not conclusive, no evidence that any of these had been eaten by the salmon was obtained. On the first two or three days, while the smolts were still in fresh water, it was once or twice observed that fragments of the prepared foods (not liver) were picked up by them after reaching the bottom of the tank; but this never occurred afterwards, and even the living Nerets, which happened to reach the bottom, were allowed to remain there crawling about, without the salmon paying any attention to them. In marked contrast to this, some Rainbow Trout (Salmo irideus), which the Duke of Bedford has also sent. to the Laboratory from Endsleigh, will commonly follow their food to the bottom, and continue to pick it up for some time after it has. settled. These Rainbows, too, easily adapt themselves in sea water to the cut Squid (ZLoligo), and some other foods ordinarily given to. the marine fishes. First Spawning, 1906-7.—Signs of approaching maturity became apparent in the smolts towards the end of October, 1906, Le. eight. months after they were first passed into sea water. On October 31st and November Ist it was observed that scarcely any food was taken, and in some cases what was taken into the mouth was discarded again. During the previous week the fish had been growing darker in colour. They began to frequent the bottom of the tank and to lie there heavily. One of them lost the upright position, and died in a day or two afterwards (November 4th). It was accordingly decided to pass. sixteen of the more advanced ones into fresh water. The process was begun on November 6th, and the change was made in a very similar manner to the reverse one in the preceding March. The time allowed AT THE PLYMOUTH LABORATORY. 307 was from two to three days, and the whole of them were thus trans- ferred to fresh water by November 15th. On November 9th, shortly after the change to fresh water, one of the males died. The testis was found to be nearly mature. The weight of this fish was very nearly 1 Ib., and the length 132 inches. During this period one of the fish jumped from the fresh-water tank into a tank of sea water adjoining (cp. p. 305). After thirty-six hours it was put back into the fresh-water tank direct without any ill effects arising. November 26th. All of the grilse were examined by Mr. MeNicol, who has charge of the Duke of Bedford’s Fishery. Apart from the deaths that had been recorded, it was found that five of the fish were missing, It can only be surmised that these had from time to time jumped over the barrier into the large adjoining tank and fallen victims to the turbot, nurse-hounds, and other large fish that occupied it. The number that remained was now thirty-five. Seven females were spawned on this day (November 26th), and the ova fertilized. The remainder were spawned on December 11th. Nearly the whole of these fertilized ova were taken to Endsleigh and there hatched under normal conditions both as regards numerical proportion and the period between fertilization and hatching. They were not kept under observation for long after hatching, and there was apparently no unusual feature arising in regard to size or otherwise in connection with their development. A few ova were retained at the Laboratory and hatched under tap water, but these did not long survive the feeding stage following absorption of the yolk-sac, owing no doubt merely to the unsuitable condition of the water supply with its irresistible tendency to nurture the growth of fungus and other vegetable organisms. As regards feeding during this period of spawning, very little food was taken between the last week in October and the two respective dates of spawning, November 26th and December 11th, though feeding did not entirely cease for more than a day or so at a time. Within a few days after spawning, there was a marked change in this respect and by December 22nd the total consumption amounted to about $ Ib. of liver per day, the weight of the fish at this time averaging about 1} lb. Feeding continued at much the same point till the middle of February. It was then decided to turn the fish, numbering thirty-five, over to sea water, and this was done between February 19th and 20th. The change proved to be an unfortunate one, and the salmon at once ceased feeding. Between February 21st and 26th, seven of them died—five males and two females. These were found to still contain a quantity of ripe milt and ova respectively. Between February 25th 308 ON AN EXPERIMENT IN THE KEEPING OF SALMON and 26th they were therefore returned to fresh water, and remained thus till March 15th. This change quickly brought about a return to feeding. On March 6th the daily consumption reached ? lb. of liver and a supply of WVerezs, and the amount did not fall appreciably below this figure afterwards. The return to sea water was made between March 15th and 19th, one female, which was found to be incompletely spawned, being lost in the process. Of the succeeding period in sea water in the spring and summer of 1907 there is little to record of interest. The food consumption rose steadily to 3 Ib. of liver per day at the middle of May, and continued at about this point till the middle of August. From the latter date it began to fall, and on September 17th it dropped to 2 lb. At the end of September the salmon had to be moved, in order that the tank might be repaired. They were very susceptible to injury in handling, and four of them died before they were finally settled in their own tank. Second Spawning, 1907-8.—The salmon, twenty-one in number, were transferred to fresh water between October 1st and 5th, about six weeks earlier than in the preceding year, feeding having by this time all but ceased. After this time and up to the date of spawning they continued to take a fair quantity of Nereis with some irregularity, but little or no liver was taken. About half of them were spawned on November 15th, seven on November 29th, one on December 13th, and one on January 3rd. A large number of the fertilized ova were kept and hatched at the Laboratory, but the larve barely attained at most the complete absorption of the yolk-sac. How far the underlying causes were to be attributed to the adequate conditions of the water supply as in the previous year, it is difficult to say, but two points were particularly noticeable in this case: (1) a common difficulty in rupturing the egg- membrane, and (2) a general weakness in the embryonic circulation which hindered communication with the distal portion of the yolk-sae and retarded its absorption. In consequence of the latter difficulty a constriction arising in the yolk-sac was the direct cause of death in the large majority of cases, and the two points taken together suggested a general sickliness that had been transmitted from the parents. Attacks of fungus, which began to affect the salmon in the early part of December, 1907, had later assumed such proportions, with fatal results to several of the fish, that it was decided to transfer the remainder of them to sea water at an early date, and this was done between January 7th and 8th, 1908. Three deaths that occurred rene si * AT THE PLYMOUTH LABORATORY. 309 within two days after the latter date may be attributed entirely to bad cases of fungus, and its attendant disease, too far gone to remedy, and apparently no ill effects resulted from this early return to sea water beyond a falling off in feeding for a few days afterwards. Growth.—As previously stated the weight of the smolts when they were brought to the Laboratory in February and March, 1906, may be placed at 4 to 5 oz., and the length at 8 to 10 inches. On September 28th, 1906, one fish, taken as representing the average, weighed 1 lb. 84 oz., and measured 16 inches in length. On November 26th, 1906, twenty-seven fish were weighed prior to spawning, but not measured. The weights of these fish were as follows :— L NO. | WEIGHT SEx. CoNnDITION. lb. oz. (1) 0 14 female mature (2) 1 3 is immature (3) 1 4 e mature (4) 1 4 male * (5) i! 6 female Bs (6) rns i : (7) il 6 = immature (8) 1 6 male mature (9) Le haa female . (10) 1 6 ” ” ( 11 ) 1 6 ” ” (12) 1 6 male : (13) i 6 _ immature (14) i 8 female mature (15) 1 8 male immature (16) 1 8 female ? spawned (17) 1 10 e mature (18) 1 10 male nearly mature (19) 1 12 female mature (20) 1 12 4 immature (21) 1 12 i mature (22) 1 12 59 ij (23) i 12 male nearly mature (24) i 14 = immature (25) 1 14 female = (26) 1! 14 iy mature (27) 2 0 A barren | It is remarkable that the above weights give an average which is exactly the same as the weight of the fish selected for trial on September 28th, viz. 1 lb. 840z. It is quite conceivable that this particular fish chosen on that occasion slightly exceeded the true average, but it is evident that the average increase of weight in the two months’ interval must have been very small. On the same 310 ON AN EXPERIMENT IN THE KEEPING OF SALMON occasion (November 26th) seven of the females were weighed after spawning, with the following results :— (a) . (o) . (c) . (d) . (e) . (Gav (9) - l ee CO MOF, SF SP DOS jl These give an average of 1 lb. 6 oz. nearly. The weights cannot be compared individually with those taken before spawning, since to obviate as far as possible excessive physical strain on the fish the weights before and after spawning were not taken in any definite sequence. If, however, the average weight 1 1b. 6 oz. be compared with that of the twelve mature females enumerated in the first list (thus omitting No. 1 for obvious reasons), namely 1 lb. 8°5 oz., the average weight of spawn removed works out at 24 0z., or 10°2 per cent of the average weight of fish. Assuming, on the other hand, that the females spawned were the seven heaviest of the mature females in the first list, then the latter give an average weight of 1 lb. 10} 0z,, and the highest possible average weight of spawn removed would thus be 43 0z., or 17 per cent of the average weight of fish. On November 15th, 1907, ie. at the time of the second spawning, the weights were again taken of seven fish, of which the females were weighed both before and after spawning. These were as follows :— Males (1) 2 Ib. 8 oz. 5) (2) a18 39 8 ” Females (1). Before spawning, 21b. 100z. After spawning, 1 1b. 14 oz. (2) if Pies; Oh, a jee (3) ; A rad bhi “4 I Axenletes (4) ” 3 ” 0 ” ” 2 ” 4 2) (5) Pd 3 ” 0 3? ” 2 9 2 ) The average weight of these five females at this date is therefore 2 lb. 12°8 0z., while the average weight of spawn removed from them is 13:2 oz. This weight of spawn thus constitutes as much as 29°5 per cent of the average total weight, and amounts in one individual (No. 2) to one-third of the total weight of the fish. On June 19th, 1908, four of the salmon were weighed and measured as representing an average sample of the twelve that remained at the Laboratory. The figures obtained were :— AT THE PLYMOUTH LABORATORY, sal WEIGHT. LENGTH. lb, 02. inches. (ii: eee es ean 19 (\ See Ss 4 “if 19} (2 ee a ees Caer) 24 202 (4) 5s 20 224 It must, however, be mentioned that the weight given for the last fish, 51b., is inconsistent with a subsequent test two months later, in which the heaviest fish weighed 4 lb. 8 oz. There is no ground for supposing that an error occurred in the reading, but it is difficult to understand such a loss of weight in the interval, and it is safer to omit these four weights in considering the average rate of growth. It was subsequently decided by the Duke of Bedford that as little information was likely to be added by retaining the salmon any longer at the Laboratory they should be liberated. On August 20th, 1908, the remainder were therefore marked and turned out into the sea, out- side the Plymouth Breakwater. Some of them were already showing signs of approaching maturity for the third time, and in one of them that died before being liberated the ovary was much developed. In- cluding this last individual, the weight of these eleven fish at this date was as follows :— Were! RaeRe. Dye Oz inches. (1) Dae! 17 (2) PI 19 (3) at 19 (4) 3. 8 19 (5) omer 20 (6) Lei) 21 (7) 4 0 21 (8) | 21 (9) Lo al 21 (10) prea 2] (11) 4 8 22 giving an average weight of 3 lb. 93 oz., and an average length of 20 inches. Summarizing the above data, the following show the averages of growth at intervals, during the period of about two years and a half, in which the salmon were kept at the Laboratory :— DATE. Approx. AGE. AVERAGE WEIGHT. AVERAGE LENGTH, 02. inches. 1906. Feb. to March 2 years 0 4} ss » Sept. 28th 7 ae eee 1 84 (approx.) 16 (approx.) » Nov. 26th seed he aeeeig. aa: 1 83 a eo Pei. 55 loth Sees >a 2 — = 1908. Aug. 20th ays a «| OF h- 820 ss? er Se hel : E ; “#8 * S ae ” < * — “7 Fe ee i id Pa eG ‘a - ; be <2 “¢ Bes ™ 312 ON AN EXPERIMENT IN THE KEEPING OF SALMON. ati Sn The average rates of growth per month, from the smolt stage in February and March, 1906, are therefore :— For nine months to November 26th, 1906 : . 2°2 oz. per month, 5» twelve os. = 5, if 15th, 1907 . {AGG 99 {5 Mane.» og Ameust = 20th 2908 ‘ Ble Miya > It only remains to mention that the form which the salmon assumed was quite an abnormal one. The silvery colour of the smolts after entering sea water was not retained, but the dorsal region became dark and much spotted. This tendency increased till ultimately the greater part of the region above the lateral line was much dark- ened and the spots increased in size and in number, extending over the whole length of the body, and in places considerably below the lateral line, being especially large and prominent about the head and gill-covers. The accompanying figure (Plate XXIV.) illustrates these points in the female, weighing about 4 lb. which died on August 20th, 1908, the date on which the remainder of the salmon were liberated. The flesh of this fish was found to have no appear- ance of the normal “salmon” colour, but was of a pale brownish white. ee ee ‘ole “anf of (URIS ONTFS) NOWTVS wae “AIXX ld TITA ‘JOA “00s8p ‘joLg any “wenor puede On the Genus Cumanotus. By Sir Charles Eliot, K.C.M.G. (See Eliot on Coryphella beawmonti in Notes on some British Nudibranchs, Journ. Mar. Biol. Assoc., vol. vii, No. 3, June, 1906, pp. 361-3; and Nils Odhner on Cumanotus laticeps in Northern and Arctic Invertebrates, iii. Opisthobranchia, Kngl- Svenska Vetenskapsakademiens Handlingar. Band 41, No. 4, 1907, pp. 29, 80, and 101-2). In describing (1.c.) Coryphella beawmonti as a new species, I pointed out that in many important characters it differs markedly from the other known Coryphelle, and might be made the type of a new genus. But I did not create a new genus, thinking it might be well to examine further specimens, both of this animal and of allied forms, before deciding on its place in the classification. In the next year Odhner created (Le.) the genus Cumanotus,* to which Coryphella beawmonti is certainiy referable, and which is shown by his researches to be well characterized. It is allied to Coryphella inasmuch as it has un- perfoliate rhinophores, tentacular angles to the foot, a triseriate radula and denticulate jaws; but it also possesses the following special characters: (1) The oral tentacles are very small and connected by a cutaneous fold which runs across the head; (2) there are several (at least, as many as three) rows of cerata in front of the rhinophores ; (3) the verge is deeply grooved, and there is a bursa copulatrix, the entrance to which bears on its upper and lower margin a circular pad, armed on the periphery with twelve small cones terminating in hooks. In the specimen which I dissected, the reproductive organs were much contracted, and I supposed these cones to be an armature on the male genitalia, such as is not uncommon in aeolids; but a dissection of more specimens, as well as an examination of the animals in life, has shown that Mr. Odhner is perfectly correct in describing the arrange- ment as two pads placed at the entrance of the bursa copulatrix. I have not seen the animals alive myself, but Mr. L. R. Crawshay, who observed their movements in the tanks of the Plymouth Laboratory, writes to me that: “Though in appearance the arrangement suggests * He says it is from kiua, a wave, and varov, back ; but if so, would not Cymanotus be the more usual form ? = 314 ON THE GENUS CUMANOTUS. that the hooked pads are associated with the ¢ rather than with the 2 organ ... at the same time, what was observed in the Laboratory points strongly to the conclusion that they are really ¢ clasping organs. If the organs of the one individual are called A (¢), B (92), and of the other, X (3), Y (2), what was observed was as follows: The two individuals were placed right to right with the complete apparatus of both extended and approximating. The base of A (¢) was grasped laterally by an upward extension (i.e. presumably the pads) on both sides of Y (?), and the base of X (3) was similarly grasped by upward lateral extensions of B(¢). In each case a sort of peristaltic movement on the part of B(?) and Y (?) occurred. As the grasp of B (¢) and Y (¢) extensions relaxed, the flow of spermatozoa from X (36) and A (¢) respectively was distinctly visible, while as the grasp of the extensions closed round the base of X (¢) and A (4), the flow of spermatozoa was checked.” As far as I am aware, a female clasping organ of this kind has not yet been recorded among Nudi- branchs, but it is possible that in some other genera of aeolids its nature may have been misunderstood. It is doubtful whether Cumanotus*beaumonti and Cumanotus laticeps are specifically the same. The identity is not improbable, but Odhner’s specimens (judging from the figures) had lost all the cerata. Cumanotus beaumonti is remarkable for having a short truncated body and extremely long snaky cerata, but when these have fallen off the Plymouth specimens look very like Odhner’s figures, and have the margin of the foot similarly expanded. There may also be differences in the denticulation of the jaws and lateral teeth. But these are slight divergences, and hardly of specific value unless associated with others. Still, until a complete specimen of the Norwegian form has been examined it is safer not to unite the two species, and provision- ally I think the genus may be tabulated as follows :— Cumanotus, Odhner, 1907. 1. C. beaumonti (Eliot), 1906. 2. C. laticeps, Odhner, 1907. If the species are united the name beawmonti has priority. I hope to publish figures of the living C. beawmonti in a supplement to Alder and Hancock’s British Nudibranchiate Mollusca, which will soon be issued by the Ray Society. C. laticeps is known by four specimens obtained at Sdrveer, in the extreme north of Norway, in 5-10 fathoms of water. C. beawmonti has been captured at Plymouth, twice in Barn Pool and on several occasions in Jennycliffe Bay, at a depth of 2-5 fathoms, and though far from common, appears to be a resident and not merely a visitor. Note on a Hermaphrodite Cod (Gadus morrhua). By A. E. Hefford, B.Sc., Assistant Naturalist at the Plymouth Laboratory. With one Figure in the Text. On February 27th, the roe of a cod having a testicular portion attached was received at the Laboratory from Messrs. Moodys and Kelly, of Grimsby. It had been taken from a cod caught by a steam trawler fishing in Icelandic waters. Owing to the rough removal of the organs from the fish on the trawling ground, the genital ducts were missing and the region of their origin was ruptured, while the testis had been somewhat damaged in the course of its long journey to Plymouth. Fig. 1 shows a drawing of the organs seen from the ventral side. The female element predominates, the ovaries appearing quite normal and functional, with unripe ova at a stage of development which suggests that spawning should occur in about two to four months.. The left ovary is 64 inches long and the right one 6} inches—a practically symmetrical condition. The testicular portion is connected with the left ovary by a duct a quarter to half an inch long, enclosed by a continuation of the fibrous covering of the ovary, the point of connection being very near to the median line and about a quarter of an inch behind the anterior extremity of the median ovarian mass. The form of the testis is rather rosette-like and frilled, but much less lobulated than a normal testis. The length of the longest lobe of the rosette measured from the duct is about 3 inches. It is now rather broken, however, and the original length was probably a little greater. Internally the testis duct is longitudinally ridged, one of these ridges widening into a valve-like flap near the small aperture which leads - Into the lumen of the ovary. The testis is in a well-developed but unripe condition. Owing to maceration in the course of transit— on the trawler it was kept in ice and then sent through the post to. “ 316 NOTE ON A HERMAPHRODITE COD. Plymouth wrapped up in paper in a box—the tissue is not suitable for microscopic examination. would be functional, and that when ripe its products would pass to the exterior via the testis duct and the ovary. Owing to the ruptured condition of the right ovary in the region corresponding to the testis i \\\ NT 1.0. Fic. 1.—Hermaphrodite Gonad of Cod. r.0.; right ovary ; l.c., left ovary ; t., testis; c.d., testis duct. duct attachment on the left, I am not able to say with absolute certainty that the above-mentioned is the only testicular part, though there is extremely little doubt but that the whole of the genitalia were removed from the fish, the ruptured portion being the result of tearing away the roe from its duct to the exterior. OS It is probable, however, that the male organ “=e NOTE ON A HERMAPHRODITE COD. 317 Other examples of hermaphroditism in cod have been described by Howes,* Masterman,}+ Williamson,t etc. Masterman gives a tabular list of eleven cases for comparison, including his own observation and those cited by Howes. In all these the ovarian organ preponderates. Great diversity is shown in the position of the testis, which may be single or in as many as three distinct and separately attached parts. In Williamson’s two cases, one presents a perfectly symmetrical form with a small testis attached to the anterior end of each ovary, while the other is completely asym- metrical, the right gonad being an ovary and the left a testis, the two uniting in the anal region and having a common genital aperture. My specimen presents a further variation in the position of the testis. In the relatively large size of the testicular portion it is also peculiar. * G. B. Howes, ‘‘ Hermaphrodite Genitalia of the Codfish,’”’ etc. (Journ. Linn. Soc., XXilil., p. 539). + Masterman, ‘‘On Hermaphroditism in the Cod” (Thirteenth Annual Report of the Fishery Board for Scotland, Part III, for the year 1894, p. 297). ~ Williamson, ‘‘On Two Cases of Hermaphroditism in the Cod” (Twenty-fourth Annual Report of the Fishery Board for Scotland, Part III, for the year 1905, p. 290). [ 318 ] Note on a Conger with Abnormal Gonad. By A. E. Hefford, B.Sc. With one Figure in the Text. AMONG a sample of seven small Conger, from 58 to 77 cm. in length, obtained from the Plymouth Fish Quay on 31st March, one was found with unsymmetrical reproductive organs. The other six were im- mature females with the normal pair of ovaries. The abnormal specimen has a right gonad quite similar to the ovaries of females at the same stage of maturity. It is bandlike in form, extending along the whole length of the abdominal cavity. The inner or left side is covered with smooth peritoneal epithelium (mesoarium). The greater part of the surface of the right (outer) side is raised into transverse lamelle containing the as yet little-developed ova embedded in fat- tissue. For about one to two millimetres from its free edge, the organ consists of a strip of fat-tissue quite free from germinal cells, and there is a similarly constituted longitudinal fold—here and there divided into a subsidiary one—extending parallel to and about 2 mm. from the free edge and bordering the lamellated germinal area. The ovary is 17:5 em. long, its greatest width 12 mm., and the widest part of the lamellated area is about 7 mm. The left gonad is a sterile ovary, the transverse germinal ridges being quite absent. Along the line of attachment there is a narrow longitudinal ridge of fat-tissue, fairly well developed anteriorly, but becoming discontinuous towards the hinder end; then a narrow strip of bare peritoneal epithelium (the area which is normally covered with the egg-bearing lamelle); and along the free edge are folds of fat- tissue similar to those occurring in the normal ovary. I am indebted to Mr. J. T. Cunningham for his kindness in examin- ing and giving his opinion upon this specimen. It is interesting to note that this abnormal individual was the sixteenth Conger examined by me since March 14th with the object of NOTE ON A CONGER WITH ABNORMAL GONAD. 319 obtaining a male specimen; but up to this time only females had been found. ‘The sizes ranged from 92 to 58 cm., ten of them being less than 76 cm. (2 ft. 6 inches) which is the limiting size given by Cun- | Fie. 1.—Abnormal Gonad of Conger. A, anterior ; A!, posterior end of right (normal) gonad. B, anterior ; B!, posterior end of left (abnormal) gonad. 0, egg-bearing lamelle ; f, fat-tissue along attachment edge of ovary; f1, fat-tissue along the free edge of ovary. p, peritoneal tissue (mesoarium). ningham* for male Conger. Subsequently I have obtained two males, of 61 cm. (24 inches) and 50 cm. (20 inches) out of twenty trawl- caught Conger ranging from 77 to 50 em. in length. * J. T. Cunningham, ‘‘On the Reproduction and Development of the Conger” (Journ. M.B.A., vol.ii, N.S., p. 31). NEW SERIES.—VOL. VIII. NO. 3. Z. [31820 2 Wlarine iological Association of the Gaited Aingdom. Report of the Council, 1907-8. The Council and Officers. Four ordinary and one special meetings of the Council have been held during the year, at which the average attendance has been ten. All the meetings have been held in the rooms of the Royal Society at, Burlington House, and the Council desire again to express their thanks to the Royal Society for the use of these rooms. Cominittees of the Council have visited and inspected the Labora- tories at Plymouth and Lowestoft, and have reported favourably on the condition of buildings and boats. The Committee on Fishery. Investigations, appointed by the Treasury to inquire into the future conduct of such investigations in the United Kingdom, have visited the Plymouth and Lowestoft Laboratories and inspected the steam-trawler Hualey. Evidence was given before this Committee on behalf of the Association by Sir E. Ray Lankester, Dr. A. E.Shipley,; Mr. J. .A: Travers, Proi..G, C. Bourne; Dr Ga Fowler, Dr. H. R. Mill, Dr. E. J. Allen, Prof. W. Garstang, and Mr. D. J. Matthews. The Laboratories. A number of necessary repairs to the building and to the aquarium tanks at the Plymouth Laboratory have been carried out during the year, and a new centrifugal pump has been fitted for circulating the sea-water through the tanks. The main laboratory, the library and other portions of the building have been colour-washed. The work of the Lowestoft Laboratory has been conducted in the same house as last year. REPORT OF THE COUNCIL. ook The Boats. The steam-trawler Huzley, which has been for five years hired by the Association for the work of the English section of the Inter- national Investigations, has now been purchased upon favourable terms by the Marine Biological Association from her owner, Mr. G. P. Bidder. Both the Huxley and the Oithona, the corresponding boat at Plymouth, were laid up during the winter months, and after under- going full surveys were put into a condition of proper repair. The sailing-boat Anton-Dohrn was used for the collecting work at Plymouth during the winter. The Staff. At the end of September, 1907, Dr. Walter Garstang resigned the post of Naturalist in Charge of Fishery Investigations, which he had occupied since 1897, in order to take up professorial duties at the University of Leeds. The Council did not feel justified in making a new appointment to his post, until H.M. Government had decided to continue the British share of the International Inves- tigations for a further term of years. The Council desires to record its appreciation of the valuable help rendered to the work by Dr. Allen, the Director, in undertaking temporarily the difficult task of superintending both the Laboratories. Since Prof. Garstang’s retire- ment Dr. Allen has resided chiefly at Lowestoft, and visited Plymouth when necessary. Mr. L. R. Crawshay has been promoted to be Assistant Director of the Plymouth Laboratory, and Mr. J. O. Borley to be Assistant Director of the Lowestoft Laboratory. Mr. A. E. Hefford has been transferred from Lowestoft to Plymouth, where he is specially engaged in the study of fishes and fishery questions. Mr, A. J. Mason-Jones, M.sc., of the University of Birmingham, has succeeded Mr. W. Bygrave as Assistant Naturalist for Plankton in connection with the International Investigations. Mr. E. W. Nelson has been temporarily employed at Plymouth ‘during the year. Occupation of Tables. The following Naturalists have occupied tables at the Plymouth Laboratory during the year :— W. C. DE Morean, London (Crustacea). J. C. Smrpsoy, Cambridge (Echinodermata). C. H. O’Donoauue, London (Hydrozoa). A. J. Grove, Birmingham (Protozoa). F. W. GAMBLE, D.Sc., F.R.S., Manchester (Colour Physiology of Fishes). G. W. Sirsa, B.A., Oxford (Sacculina). O22 REPORT OF THE COUNCIL. F. J. Bripceman, London (Development of Porifera and Elasmobranchii). R. D. Lauriz, M.A., Oxford (Crustacea. Biometrical Study), E. T. Browne, B.A., London (Ccelenterata). W. ByGrave, B.A., Cambridge (Plankton). DAVIDSON, Pigaaeuee (Plankton Larve). F. Fryer, Cambridge (General Zoology). Goopricx, M.A., F.R.S., Oxford (Thymus of Fishes). Roprnson, London (General Zoology). . M. Ricuarps, London (General Zoology). Miss W. CowarD, Manchester (General Zoology). Miss H. L. M. Prxetz, B.sc., London (Ferments of Digestive Tract of Elasmobranchii). Sir Caarues Exr07, K.c.M.¢., Sheffield (Nudibranchiata). Miss A. IsGRovE, B.Sc., Manchester (Eledone). H. M. Fucus, Brighton (General Zoology). Mrs. O. A. Meritr Hawkes, M.sc., Birmingham (Embryology and Nervous System of Elasmobranchii). H. H. Bioomer, Birmingham (Psammobia). G. H. Grosvenor, B.A., Oxford (General Zoology). . Rk. oC! xe gi Twenty-five students attended a course of study in Marine Biology conducted at the Laboratory during the Easter vacation by Mr. G. H. Grosvenor. The Library. The thanks of the Association are due for the following books and current numbers of periodicals presented to the Library during the past year :— Académie Imp. des Sciences de St. Pétersbourg. Bulletin. American Museum of Natural aus Bulletin. — Memoirs. — Report. American Microscopical Society. Transactions, American Philosophical Society. Proceedings. Armstrong College. Calendar. Australian Museum. Memoirs. — Records. Report. Bergens Museum. Aarbog. An Account of the Crustacea of Norway, ete. ; by G. O. Sars. Bernice Pauahi Bishop Museum, Honolulu. Occasional Papers. Fauna Hawaiiensis. Board of Agriculture and Fisheries. Annual Report of Proceedings under the- Salmon and Freshwater Fisheries Acts. Report of Proceedings of 16th Annual Meeting. Boston Society of Natural History. Proceedings. Bristol Naturalists Society. Proceedings. British Association for the Advancement of Science. Report. British Museum. National Antarctic Expedition, 1901-4. Natural History. Brooklyn Institute of Arts and Sciences. Science Bulletin. Brown University. Contributions from the Anatomical Laboratory. REPORT OF THE COUNCIL. 323 Budgett Memorial Committee. The Work of John Samuel Budgett. Bulletin Scientifique de la France et de la Belgique. Cairo Zoological Gardens. Report. —— Additions to the Menagerie. The Cancer Research Fund. Scientific Reports on the Investigations. Cardiff Incorporated Chamber of Commerce Report. The Carnegie Institution. Publications, College of Science, Tokyo. Journal. College voor de Zeevisscherijen. Verslag van den Staat der Nederlandsche Zeevisscherijen. Colombo Museum. Spolia Zeylanica. The Commissioners of Fisheries, N.S. Wales. Report. Conchelogical Society of Great Britain and Ireland. Journal of Conchology. Conseil perm. internat. pour Exploration de la Mer. Bulletin des Résultats acquis pendant les Courses Peériodiques. — — Publications de Circonstance. —— Rapports et Proces-Verbaux des Réunions. Cuerpo de Ingenieros de Minas del Peru. Boletin. Danish Biological Station. Report to the Board of Agriculture. Kgl. Danske Videnskabernes Selskab. Oversigt. —— Skrifter. Dept. of Agriculture, etc., Ireland. Reports. Dept. of Commerce and Labor, U.S.A. Report of the Commissioner of Fisheries. Dept. of Fisheries, N.S. Wales. Additions to the Fish-Fauna of New South Wales. By D. G. Stead. Note on a small Collection of Fishes from Suwarow Island. By D. G. Stead. Preliminary Note on the Wafer (Leptoplana australis). By D, G. Stead. Dept. of Marine and Fisheries, Canada. Annual Report. Deutsche Zoologische Gesellschaft. Verhandlungen. Deutscher Fischerei Verein. Zeitschrift fiir Fischerei. Deutscher Seefischerei Verein. Mitteilungen. Falmouth Observatory. Meteorological and Magnetic Reports. La Feuille des Jeunes Naturalistes. Field Museum of Natural History. - Annual Report. Publications. Finnlandische Hydrographisch-Biologische Untersuchungen. Fisheries Society of Japan. Journal. Fishery Board of Scotland. Annual Report. Fiskeri-Beretning, 1905-6. Fiskeriniringen i Sverige, Atgiirder. 1906. Flodevigens Udklaekningsanstalts. Bidrag. 1892-1907. Government Museum, Madras. Report. Hertfordshire Museum Report. R. Irish Academy. Proceedings. Kansas University. Science Bulletin. Kommission zur wissenschaftlichen Untersuchung der Deutschen Meere, etc. Wissenschaftliche Meeresuntersuchungen. Kommissionen for Havundersiégelser, Copenhagen. Meddelelser, series Fiskeri, Hydrografi, Plankton. —— Skrifter. 324 REPORT OF THE COUNCIL. Kgl. Norske Videnskabernes Selskab. Skrifter. Kgl. Vetenskaps Societeten, Upsala. Stadgar. Bibliographia Linnaeana. By J. M. Hulth. Laboratoire Biologique de St. Pétersbourg. Bulletin. Lancashire and Western Sea Fisheries. Superintendent’s Report. —— Quarterly Report on the Scientific Work. Liverpool Biological Society. Proceedings and Transactions. Liverpool Marine Biology Committee. Marine Biological Station at Port Erin. Report. Liverpool University Institute of Commercial Research in the Tropics. Quarterly Journal. —— The Commercial Possibilities of West Africa. By Viscount Mountmorres. Manchester Microscopical Society. Annual Report and Transactions. Manchester University Biological Society. Publications. Marine Biological Association of the West of Scotland. Report. Marine Biological Laboratory, Woods Holl. Biological Bulletin. Mededeelingen over Visscherij. Meteorological Office. Monthly Pilot Charts, North Atlantic and Mediterranean. —— Monthly Pilot Charts, Indian Ocean and Red Sea. R. Microscopical Society. Journal. Ministére de l’Instruction Publique, France. Nouvelles Archives des Missions Scientitiques. Musée du Congo. Annales. Musée d’Histoire Naturelle, Paris. Bulletin. Musée Océanographique de Monaco, Bulletin. Museo Nacional, Buenos Aires. Anales. Museo Nacional, Montevideo. Anales. Museum fiir Meereskunde, Berlin. Fiihrer. Museum of Comparative Zoology, Harvard College. Bulletin. Memoirs. —— Report. —— Harvard University Museum: Its Origin and History. By A. Agassiz. | Louis Agassiz. 1896. By W. James. . Museum of the Royal College of Surgeons. Catalogue of Osteological Specimens. —— Catalogue of Physiological Series. . The Museums Journal. Natural History Society of New Brunswick. Bulletin Naturforschende Gesellschaft in Basel. Verhandlungen. Naturhistorischen Museum, Hamburg. Mitteilungen. Neapel. Mitteilungen aus der Zoologischen Station. Nederlandsche Dierkundige Vereeniging. Verslag. —— Tijdschrift. —— Aarwinsten der Bibliotheek. —— Catalogus der Bibliotheek. New York Academy of Sciences. Annals. New York Zoological Society. Bulletin. Report. New Zealand Institute. Transactions and Proceedings. Norges Fiskeristyrelse. Aarsberetning vedkommende Norges Fiskerier. Northumberland Sea Fisheries Committee. Report on Scientific Investigations. La Nuova Notarisia. REPORT OF THE COUNCIL, 325 Oberlin College. Laboratory Bulletin. —— The Wilson Bulletin. Otago Acclimatisation Society. Report. Oxford University Museum. Catalogue of Books added to the Radcliffe Library. Pacific Scientific Institution. Publications. Physiographiske Forening, Christiania. Nyt Magazin for Naturvidenskaberne, Plymouth Museum and Art Gallery. Annual Report. Quarterly Journal of Microscopical Science. (Presented by Sir E, Ray Lan- kester, K.C.B., F.R.8.) Queensland Museum. Annals. Rijksinstituut voor het Onderzoek der Zee, Helder. Jaarboek. Royal Society of Edinburgh. Proceedings. — Transactions. Royal Society of London. Philosophical Transactions. Proceedings. Year-Book. Royal Society of Victoria. Proceedings. Scottish Oceanographical Laboratory. Some Results of the International Ocean Researches. By J. Hjort. Selskabet for de Norske Fiskeriers Fremme. Norsk Fiskeritidende. Senckenbergische naturforschende Gesellschaft, Frankfurt. Bericht. —— Katalog der Reptilien-Sammlung im Museum. —— Katalog der Batrachier-Sammlung im Museum. —— Katalog der aus dem _ palaarktischen Faunengebiet beschriebenen Saugetiere. —— Katalog der Vogelsammlung im Museum. —— Reiseerinnerungen aus Algerien und Tunis. Von Dr. W. Kobelt. Smithsonian Institution. Annual Report of the U.S. National Museum. —— Report on the Crustacea (Brachyura and Anomura) collected by the N. Pacific Exploring Expedition, 1853-6. By W. Stimpson. Sociedad Scientifica de Sao Paulo. Revista. Société Belge de Géologie, ete. Bulletin. Société Centrale d’Aquiculture et de Péche. Bulletin. Societa di Naturalisti in Napoli. Bollettino. Société Enseignement des Péches Maritimes. Bulletin Trimestriel. Société d’Océanographie du Golfe de Gascogne. Rapports. Société Suisse de Péche et Pisciculture. Bulletin. Société Imp. Russe de Pisciculture et de Péche. Vyestnik R‘ibopom‘shlennosti. Société Zoologique de France. Bulletin. — Memoirs. South African Museum. Annals. --— Report. Station de Pisciculture et d’ Hydrobiologie, Toulouse. Bulletin Populaire. Kgl. Svenska Vetenskaps-Akademien. Arkiv for Botanik. Arkiv for Zoologie. —— Handlingar. Transvaal Biological Society. First Meeting. Ulster Fisheries and Biology Association. Scientific Papers. Unione Zoologica Italiana, Rendiconto. 326 REPORT OF THE COUNCIL. United States Bureau of Fisheries. Bulletin. United States National Herbarium. Contributions. United States National Museum. Bulletin. —— Proceedings. University of California. Publications. Zoology, Physiology, Botany. University of Pennsylvania. Contributions from the Zoological Laboratory. —— University Bulletins. —— Catalogue. — — Contributions from the Botanical Laboratory. University of Toronto. Studies. Kgl. Vetenskaps Societeten, Upsala. Nova Acta. Visscherij-Station, Batavia. Mededeelingen. Welsh Museum. Report. Zoological Society of Japan. Annotationes Zoologice Japonenses. Zoological Society of London. Proceedings. —— Transactions. —— Reports of the Council and Auditors. Zoological Museum, Copenhagen. ‘The Danish Ingolf-Expedition. Zoologischen Museum, Berlin. Bericht. —— Mitteilungen. To the authors of the Memoirs mentioned below the thanks of the Association are due for separate copies of their works presented to the Library :— Borley, J.O. Marine Zoology. A History of Yorkshire. Brown, E. T. A Revision of the Medusz belonging to the Family Laodiceide. —— On the Freshwater Medusa, Limnocnida tanganice, discovered in the river Niger by the late J. S. Budgett. —— The Meduse of the Scottish National Antarctic Expedition. Buchanan, F. The Time taken in passing the Synapse in the Spinal Chord of the Frog. Bullen, G. E. Notes upon Hydroids observed in Aberdeen Trawl Refuse. Cépéde, C. Contribution a l’étude de la nourriture de la Sardine. —— Quelques remarques sur la nourriture de la Sardine. Myxosporidies des Poissons des Alpes Frangaises. Clark, J. Marine Zoology. A History of Cornwall. Cligny, A. La Truite de Mer. — Les Prétendues Migrations du Hareng. —— Repeuplement des Rivicres du Pas de Calais. Cotton, A. D. Some British Species of Phwophycee. Cunningham, J.T. On Kalpidorhynchus arenicole, a new Gregarine, parasitic in Arenicola ecaudata. Dahl, Knut. The Scales of the Herring as a means of determining Age, Growth, and Migration. Darbishire, A. D. On the Direction of the Aqueous Current in the Spiracle of the Dogfish ; together with some Observations on the Respiratory Mech- anism in other Elasmobranch Fishes. —— Some Tables for illustrating Statistical Correlation. —— Recent Advances in Animal Breeding and their Bearing on our Knowledge of Heredity. REPORT OF THE COUNCIL. : 327 Dendy, A., and Hindle, E. Some Additions to our Knowledge of the New Zealand Holothurians. Dollo, L. Notolepis Coatsi, Poisson pélagique nouveau reucueilli par PExpédi- tion Antarctique Nationale Ecossaise. Note préliminaire. Edwards, C. L. The Holothurians of the North Pacific Coast of North America collected by the Albatross in 1903. —— The Order of Appearance of the Ambulacral Appendages in Holothuria floridana, Pourtales. Eliot, C. On the Nudibranchs of Southern India and Ceylon, with special Refer- ence to the Drawings by Kelaart and the Collections belonging to Alder and Hancock preserved in the Hancock Museum at Newcastle-on-Tyne. —— Mollusca. Pteropoda. —-— Nudibranchs from New Zealand and the Falkland Islands. —— Nudibranchs from the Indo-Pacific, IIT. Eliot, C., and Evans, T. J. Dorideides gardineri. A Doridiform Cladohepatic Nudibranch. Fenchel, A. Ueber Tubularia larynx, Ellis. T. coronata, Abildgaard. Gardiner, J. S. Investigations in the Indian Ocean. Second Report of the Committee. —— The Percy Sladen Trust Expedition to the Indian Ocean in 1905, I. IL. Description of the Expedition. Hartmeyer, R. Beitriige zur Meeresfauna von Helgoland, XV. Die Ascidien von Helgoland. —— Ein Beitrag zur Kenntnis der Japanischen Ascidienfauna. Helland-Hansen, B. Current Measurements in 1906. Hewitt, C. G. A Preliminary Account of the Life-history of the Common House Fly (Musca domestica, L.). Hickson, 8. J. Obituary Notice of Sir Michael Foster. —— The Differentiation of Species of Coelenterata in the Shallowwater Seas. —— Note on Caligorgia flabellum from Port Phillip. Hickson, S. J., and Gravely, F. H. Ccelentera. II. Hydroid Zoophytes. Hjort, J. Nogle Resultater af den Internationale Havforskning. Hodgson, T. V. Pycnogonida. National Antarctic Expedition. —— Pyenogoniden. Hamburger Magalhaensische Sammelreise. The Pycnogonida of the Scottish National Antarctic Expedition. Holt, E. W. L., and Byrne, L. W. New Deep-sea Fishes from the South-west Coast of Ireland. Horst, R. Ona New Cubomedusa from the Java-Sea, —— On a large Penella-species from the Moluccas. Juday, C. Ostracoda of the San Diego Region. II.—Littoral Forms. —— Cladocera of the San Diego Region. —— A Study of Twin Lakes, Colorado, with Especial Consideration of the Food of the Trouts. ; Kofoid, C. A. New Species of Dinoflagellates. —— The Limitations of Isolation in the Origin of Species. —— Dinoflagellata of the San Diego Region. I1I.—Descriptions of New Species. —— Current Zoological Literature. Lambe, L. M. Note on the Occurrence of a Supernumerary Tooth in a Dog. Loisel, Gustave. Rapport sur une Mission Scientifique dans les Jardins et Etablissements zoologiques publics et privés du Royaume-uni de la Belgique et des Pays Bas. 328 REPORT OF THE COUNCIL. M’Intosh, W. C. Notes from the Gatty Marine Laboratory. Man, J. G. de. Diagnosis of New Species of Macrurous Decapod Crustacea from the “ Siboga-Expedition.” IT. —— Sur Quelques Espéces Nouvelles ou peu connues de Nématodes libres habitant les Cotes de la Zélande. Maréchal, J. Sur Povogénése des Sélaciens et de quelques autres Chordatés. I. Meek, A. Report on the Scientific Investigations. Northumberland Sea Fisheries Committee. Murray, J. “Scotia” Collections, Note on Microscopie Life in Gough Island, South Atlantic Ocean. —— Arctic Rotifers, collected by Dr. William S. Bruce. : Norman, A. M. On some British Polyzoa. —— Notes on the Crustacea of the Channel Islands. —— Some species of Leptocheirus, a Genus of Amphipoda. —— The Celtic Province, Its Extent and its Marine Fauna. Pavillard, M. J. Sur les Ceratiéwm du Golfe du Lion. Philippi, E. ‘ Spermatophoren” bei Fischen, Pixell, H. L. M. On the Morphology and Physiology of the Appendix digitiformis in Elasmobranchs. Rathke, Jens. Afhandling om de Norske Fiskerier og Beretninger om Reiser i Aarene, 1795-1802, for at Studere Fiskeriforhold, M.V. Reed, T. E. The Sex Cycle of the Germ Plasm. Ricciardi, L. L’Unita delle Energie Cosmiche. Shipley, A. E. Walter Frank Raphael Weldon. 1860-1906. —— The late Prof. Sir Michael Foster, K.c.B. -—— Sea Fisheries. Todd, R. A. Marine Zoology. A History of Devonshire. Thornely, L. R. Report on the Marine Polyzoa in the Collection of the Indian Museum. Tregelles, G. F. Sea Anemones and Corals of Cornwall. Trybom, F. Ichthyologische Beobachtungen auf den Laichplitzen der Lachse und Meerforellen im Unterlauf des Flusses Dalelf in Schweden. —-— Markierungen von Lachsen und Meerforellen im Ostseegebiete. Trybom, F., and Schneider, G. Das Vorkommen von “Montées” und die Groesse der Kleinsten Aale in der Ostsee und in deren Fluessen. —— Die Markierungsversuche mit Aalen und die wanderungen gekennzeich- neter Aal in der Ostsee. Walker, A. O. Amphipoda. National Antarctic Expedition. Weber, S. E. Polygenesis in the Eggs of the Culicide. —— Mutation in Mosquitoes. General Work at Plymouth Laboratory. Several reports on the material collected by the Hualey from the north side of the Bay of Biscay in August, 1906, have been published in the Journal, whilst others are still in preparation. Mr. Crawshay and Mr. Worth have published in the Journal (vol. vui., No. 2) detailed reports on the nature of the bottom deposits found in the English Channel between the Eddystone and the fifty- fathom line, as a result of the dredging operations carried out in 1906. The biological reports dealing with these dredgings are not yet complete. REPORT OF THE COUNCIL. 329 A large number of hauls have been made in the Channel during the year with a Petersen young-fish trawl, which has proved very success- ful in capturing larval, post-larval and young stages of fishes. Mr. A. E. Hefford is engaged in the study of this material, and is also study- ing the different aspects of the fisheries in the south-western district. Mr. G. E. Bullen has continued his study of the food of the mackerel and other migratory fishes, and has prepared a report on the subject which will soon be published in the Journal. Mr. E. W. Nelson has continued a series of experiments, which had been commenced by Dr. E. J. Allen, on “ pure cultures” of Planktonic Diatoms and Algz, in connection with the rearing of pelagic larve of fish and invertebrata. Mr. C. L. Walton was temporarily engaged at the Laboratory from October to January, devoting his time chiefly to the study of the local Actiniz, and an account of some of his observations has been published in the last number of the Journal. An exhibit of tow-nets, trawls, dredges, etc., is being shown by the Association in the Hall of Science at the Franco-British Exhibition. The International Fishery Investigations. The following is a summary of the work done, and of the conclusions arrived at by the scientific staff working under the direction of the Council. Section I.—NORTH SEA WORK. AC VW ORIG VOR” EH So. abr Us ave TRAWLING INVESTIGATIONS.—From June Ist, 1907, to the end of May, 1908, the Huxley made 9 voyages, in the course of which 176 hauls of the commercial trawls were made, together with 547 hauls of various smaller nets and other gear. The total number of voyages made by the Hualey from the commencement of the investigations to the present date is 99; the total number of hauls made with commercial trawls is 1254, that with smaller gear 1153. In the spring of this year trawling investigations, which it is pro- posed to repeat at quarterly intervals throughout the year, were carried out at certain selected positions and along a line already trawled in the spring of 1905 and 1906 and the summer of 1905. In this work the ordinary commercial trawls, the Beam trawl covered with fine meshed netting as described in the last report, and various smaller nets, were used, the hauls being made as strictly comparable in time and place as is possible under the unavoidable difficulties of marine work. 330 REPORT OF THE COUNCIL. DREDGING INVESTIGATIONS.—Extensive series of hauls with Dredge, Conical Dredge and Agassiz trawl were made in the months of June, July and August in the deep water west of the Dogger and on the rough ground between Flamborough Head and Lowestoft and west of 3° KE. long. In April similar work was carried out on different grounds between 52° and 53° N. lat. In voyages 98 and 99 a small trawl with very coarse canvas netting, specially designed for the capture of small fish and crustacea, has been used with success. . FisH MEASURED.—Over 75,000 fish were measured during the year. As in past years, the entire catch was measured on nearly all occasions. The details as to the number of plaice, haddock and other species are as follows :— PLAICE. Happock. OTHERS. TOTALS. 1902-7 Voyages 1-90 107,614 47,240 253,293 ... 408147 1907-8 Voyages 91-98 32,350 L273 0. 44.954. aia ToTALS 139,964 48513 295,247 ... 483,724 Measurements of plaice accompanied by observations on maturity were also carried out, both at sea on a Lowestoft fishing-smack and at the Lowestoft market. In this way 1810 plaice were dealt with at sea in January, while in the observations on the market, which were made almost daily in November and December and at intervals throughout the first quarter of 1908, 10,786 plaice were examined. MARKING EXPERIMENTS.—During the past year 2159 plaice and 15 other fish have been marked and set free. Of the marked plaice, 1430 were transplanted from the Dutch and Danish coastal grounds to the southern shoals of the Dogger Bank in May, 1908, with a view of obtaining information as to their rate of growth in 1908-9. The more noteworthy of the remaining experiments were directed towards ascertaining the movements of plaice in autumn in the deeper water bordering the Dogger Bank, and of the spent plaice which were leaving the spawning grounds in the southernmost portions of the North Sea in spring. With these objects 278 plaice were marked at various positions round the Dogger Bank in August, 1907, and 180 plaice, including spent females of 35-40 em. in length, were marked near Smith’s Knoll Light Vessel in March, 1908. Of the plaice marked from June 1st, 1906, to May 31st, 1907, 387 or 18°7 % were returned before June Ist, 1908. Of the fish. marked in the year 1905-6, 25°6 % were returned before June Ist, 1907. These percentages are only comparable in a rough sense, since the times elapsing between the various experiments and the 31st of May following do not necessarily correspond in the two years. The difference is, how- REPORT OF THE COUNCIL. Boil ever, worthy of notice. It seems to be due to the small number of trans- planted fish recovered, the returns from the Fisher Bank being particu- larly small. Nearly two-thirds of all the fish marked were taken to the Dogger Bank, Great Fisher Bank and Little Fisher Bank: the per- centages of these recovered before June Ist, 1907, were 15:1 Y%, 10:1 {% and 2°5 % respectively, while of the fish marked in the ordinary marking experiments 34°6 % were caught again. The conditions under which they were captured being in some respects unfavourable, there is reason to think that the transplanted fish were not very strong; this, together with the differences of intensity of fishing in the areas covered by the work of the two years, probably accounts for the different rates of recapture: Of the 749 fish transplanted in April and May, 1907, to the Dogger Bank, 15 were recovered after an interval of 12 months, and show an average yearly growth of 11-1 cm. Four fish were recovered a year after liberation on the Great Fisher Bank, having increased in length by 5:0-10°7 em. Only one fish of those set free on the Little Fisher Bank was re- captured after the same period; this had grown 4°6 cm. During the year, 9 turbot, 3 cod and 3 latchets were also marked, and the following marked fish were returned: 33 thornback rays, 17 soles, 10 cod and 3 brill. Considering the small number of fish marked, and the fact that practically all were marked before June, 1907, the proportions of cod and thornbacks returned in the current year seem to indicate that the mark is fairly suitable for work with these fish. Of 295 soles marked in the year 1906-7 about 6 ¥ were recaptured before June Ist, 1908. VITALITY EXPERIMENTS.—The plaice caught in 14 hauls of the com- mercial trawl were examined with a view to the estimation of the pro- portion that would survive under various conditions of trawling, if returned to the sea either at once or after certain periods on deck. The number of plaice dealt with in these experiments is 16,163, each of which had to be examined separately. MarkeED Coconuts.—In September, 1906, 859 coconuts were put overboard in the North Sea. 142 of these nuts have now been recovered. In many cases the wire by which the label is fastened to the nut is found to be much worn, indicating a considerable amount of motion at the sea bottom on which the nut rested. B. LABORATORY WORK. Maturity oF PLaice.—During the past year the investigations with regard to the age and size of plaice at maturity in different parts of the North Sea and English Channel, and also those on the distribution of 332 REPORT OF THE COUNCIL. spawning plaice, have been continued. The results show that, on an average, female plaice are first mature when at the end of their sixth year on the grounds around the Dogger Bank, at the end of their fifth year in the southern part of the North Sea, and at the end of their fourth year in the western part of the Channel. Males, on an average, mature a year earlier than the females. There is evidence to show that spawning takes place particularly in the deep water off the Yorkshire coast and at the southern end of the North Sea, but not in the region of the Leman Banks or on the Dogger Bank. Spawning off Yorkshire appears to occur later than on the southern spawning ground. The examination of 123 otoliths suggests that local and sexual differences are reflected in the otolith, owing to a diminution of growth at maturity. The data are not however considered to be as yet suffi- cient for the satisfactory substantiation of this conclusion. The material for this research consists in observations on the size and maturity of 13,247 plaice, in 4,106 of which the age was determined from the otoliths. OBSERVATIONS ON PLAICE IN THE BARENTS SEA.—By the kindness of Messrs. Hellyer, a member of the staff was enabled to make a voyage to the Barents Sea in a Hull trawler, in August last. In the course of this voyage 2,146 male and 2,365 female plaice were measured. The “average size at first maturity,” ie. the length at which 50 % are mature, was found to be about 40 em. for female plaice from the Barents Sea; which is the same as for those from the central grounds of the North Sea. Whereas, however, in the Barents Sea the great majority of the plaice caught on the voyage were considerably above this “average size at first maturity,’ and had therefore spawned once at least, the majority of plaice examined in the North Sea were below it, most of them not having spawned at all before being caught. The North Sea thus is in the condition which theoretically should result from the overfishing of such a plaice population as that of the Barents Sea. The rate of growth of the Barents Sea plaice appears to be slow, possibly owing to the low temperature (about 2° F. above freezing point) which prevails. There is some evidence that the plaice migrate towards Atlantic water for spawning purposes, as do those of Iceland. An account of this voyage appears in the Journal of the Associa- tion, vol. viil., p. 71. VITALITY OF TRAWL-CAUGHT PLaicE.—A report has been prepared REPORT OF THE COUNCIL. Boo on the results of the experiments carried out on this matter by the Huxley. The fish tested were derived from 12 Otter- and 16 Beam- trawl hauls of different duration. The catches varied in nature and weight. Each catch was tested in sections, batches of fish being placed in tanks of circulating sea-water after various periods of exposure; the total number of such batches was 89. Consideration of the data obtained leads to the conclusion that few of the small plaice captured in the process of commercial trawling would survive if returned to the sea immediately after they reached the deck; while if returned, as in practice they would be returned, after the fishermen had dealt with the marketable catch, the percentage surviving would be extremely small. The Otter trawl is found to injure a far greater proportion of the fish than the Beam trawl, though probably the very long hauls of the latter which are quite commonly taken by the sailing vessels using these trawls would produce the same effect as the hauls with the Otter trawl. Long hauls, the presence of J/eduse in the net, hot sunshine during the time the fish are on deck and probably heavy catches are all detrimental to the fish. MIGRATION OF Cop.—A brief report on this subject has also been completed. It is based on the 252 cod marked on the Huzley and the 42 recaptures recorded up to the date of writing. Most of the recaptures, constituting 13 % of the healthy fish liberated, took place within six months of liberation. The fish below 60 cm. in length appear to have remained in water of depth similar to that in which they were first caught, and had not travelled far. Most of those which had moved some distance from the liberation point were recaptured south or west of it. The number of these is however small. Fifteen cod which remained for more than three months at liberty showed an average rate of growth of 15 cm., but afforded no indications of different growth rates at different seasons. Foop oF FISHES.—Since the conclusion of the second report on this subject the stomachs of 2,040 fish, belonging to 24 species have been examined and their contents identified. The total number of fish subjected to examination during the investigations is 11,866, drawn from 39 species. INVERTEBRATE FAuNA.—The preparation of a report on the distribu- tion of invertebrates in the North Sea, based on the operations of the Huxley, is in progress. The report will deal with 2,168 hauls made before the end of 1907. 334 REPORT OF THE COUNCIL. Bortom Deposits.—During the year the collection of bottom samples has been increased by 161, and is now 549. All those collected before the end of 1907 have been classified by reference to type specimens and graded by the use of sieves with holes ranging from 15:0 to 0°5 mm. diameter. The percentage of silt has also been estimated in each case, and the shells present have been identified. In certain typical samples the chief minerals have been determined. Elementary chemical examination of these samples is proceeding. Taken as a whole the material shows that wide areas exist over which the condition of the bottom is exceedingly uniform, and that these areas are confined to the central and eastern parts of the North Sea: west of 2° E. long. the ground is extremely irregular and for the most part coarse in texture. The distribution of considerable quantities of the various grades of deposits on the offshore grounds can be defined with some confidence in the south part of the North Sea. C. FISHERMEN’S RECORDS. There has been no change in the method of carrying out the collec- tion and examination of fishermen’s records. A report on the records of the catches of plaice and soles obtained from Lowestoft smacks has been completed. It deals with 4,929 hauls, made in the years 1903-6, and shows that the average catch of plaice per six hours’ fishing, by the three boats whose records are considered, markedly declined during this period. The catch of soles also declined, though after 1905 the decrease was very small. No conclusion as to the cause of this general decline in the years considered has been reached. The catches of turbot and brill have been treated in a similar manner, that of turbot showing a continuous decline, that of brill falling until 1905, and then rising; the numbers of these two species caught are not, however, great. The treatment of the Grimsby records, obtained from steam-trawlers, is proceeding. 13,535 hauls made in the years 1904-7 have been tabulated by areas, and the monthly average catches of turbot, brill, and soles determined together with that of plaice for 1905. Section Il.—HYDROGRAPHIC AND PLANKTON WORK IN THE ENGLISH CHANNEL. During the past twelve months the hydrographic investigations have been carried out according to the programme of recent years, and the quarterly cruises have been extended into the Irish Channel nearly as far north as the Smalls. A large number of samples of water have been received from outside sources, while the establishment of a regular weekly sailing between Plymouth and Brest by the G.W.Ry. Co. has Oat. REPORT OF THE COUNCIL. 335 made it possible to obtain surface samples every fortnight on this line, so that a continual record can be kept of the surface changes over the whole of the English Channel. During the month of August, 1907, salinities were, on the whole, somewhat low, At the south-west extremity of the area investigated the water was of the same composition from top to bottom, which is somewhat unusual at this season; to the north of this, however, at about sixty miles true south of the Scilly Islands, a distinct division into layers of different origin was found, and this condition could be traced in a northerly direction to the Smalls Lighthouse. The November cruise showed that the waters of the Irish Channel were becoming more homogeneous, while in the western part of the English Channel a more pronounced division into layers of varying salinity had appeared. The investigations in the eastern area had to be considerably curtailed owing to continued bad weather. During December, 1907, the surface conditions, as shown by samples received from liners and cross-channel steamers, were decidedly ab- normal. Irregular patches of water of very high salinity appeared to the south-west, off the Cornish coast, while the salinity between New- haven and Caen fell to below 34 parts per thousand. During January and February the high salinity water advanced eastward, and there is reason to suppose that in April it had reached the line joining the Isle of Wight and Havre. The low salinities found between Newhaven and Caen during December were not found in January, and it is probable that they were due to a thin surface layer which would be quickly obliterated by mixing. During the year samples of Plankton were taken in the usual manner on the four quarterly cruises, and also at regular intervals at Plymouth, and at light-vessels on the English and Irish coasts. Samples were also taken each week, midway between Plymouth and the Channel Islands, from the s.s. Devonia. The records of species taken on the quarterly cruises are published in the Bulletin of the International Council. The samples taken during the August cruise at one station in the Bristol Channel (E. 30) contained pieces of a peculiar Siphonophore, apparently Lychnagalma, Haeckel. This was also found off Ushant in November. The appearance of two small Protozoans, Dictyocysta elegans, Ehrb., and Dictyocysta mitra, Haeck., at the Western Stations in November are of interest in connection with the peculiar hydro- graphic conditions of the English Channel and the North Sea during that month. These organisms, according to Brandt, have a distinctly Atlantic distribution. 3 NEW SERIES.—VOL. VIII. NO. 3. PAIX 336 REPORT OF THE COUNCIL. Published Memoirs. The following papers, either wholly or in part the outcome of work done at the Laboratory, have been published elsewhere than in the Journal of the Association :— Corton, A. D.—Some British Species of Phaeophycee. Journal of Botany, vol. 45, 1907, pp. 368-373. DARBISHIRE, A. D.—On the Direction of the Aqueous Current in the Spiracle of the Dogfish ; together with some Observations on the Respiratory Mechanism «in other Elasmobranch Fishes. Linn. Soc. Journ. Zool., vol. 30, 1907, pp. 86-94. Hopeson, T. V.—Pycnogonida. National Antarctic Expedition. Natural History, 1907. Hopeson, T. V.-—The Pycnogonida of the Scottish National Antarctic Expedition. Trans. Roy. Soc., Edinburgh, vol. 46, Part I., 1908. MacBripg, E. W.—Some Points in the Development of Ophiothria fragilis. Proc. Roy. Soc., Ser. B., vol. 79, pp. 440-445. MacBripg, E. W.—The Development of Ophiothrix fragilis. Quart. Journ, Micr. Sei., vol. 51, 1907, pp. 557-606. Smitu, Grorrrey.—The fixation of the Cypris Larva of Sacculina carcini (Thompson) upon its Host, Carcinus maenas. Quart. Jour. Micr. Sci., vol. 51, 1907, pp. 625-632. Wooptanp, W.—Studies in Spicule Formation, VII. The Scleroblastic development of the Plate-and-Anchor Spicules of Synapta, and the Wheel Spicules of the Auricularva Larva. Quart. Journ. Mier, Sei., vol. 51, pp. 483-509. Donations and Receipts. The receipts for the year for the ordinary work of the Association include the grants from His Majesty's Treasury (£1000) and the Worshipful Company of Fishmongers (£400), Special Donations (£40), Annual Subscriptions (£96), Rent of Tables in the Laboratory (£85), Sale of Specimens (£400), Admission to Tank Room (£134). Vice-Presidents, Officers, and Council. The following is the list of gentlemen proposed by the Council for election for the year 1908-9 :— President. Sir Ray Lanxester, K.C.B., LL.D., F.RB.S. Vice-Presidents. The Duke of ABERcorN, K.G., C.B. The Right Hon, JosrpH CHAMBER- The Duke of Beprorp, K.G. LAIN, M.P. The Earl of St. GERMANS. The Right Hon. AustEN CHAMBER- The Earl of Ducts, F.R.S. LAIN, M.P. Lord AvEsury, F.R.S. Sir Epwarp Brirxpeck, Bart. Lord Twrerpmours, K.T. A. C. L. Ginrusr, Esq., F.R.S. Lord WaLsinaHaM, F.R.S. Sir Jonn Murray, K.C.B., F.R.S. The Right Hon. A. J. Batrour, M.P., Rev. Canon Normay, D.C.L., F.R.S. F.R.S. Epwin WATERHOUSE, Esq. ae REPORT OF THE COUNCIL. aot Members of Council. G. L. ALwarp, Esq. Prof. T. W. Brinas, Sc.D., F.R.S. W. T. Caiman, Esq., D.Sc. Prof. A. Denpy, D.Sc., F.R.S. Sir Coartes Extot, K.C.M.G. G. Hersert Fowter, Esq., Pa.D. F. W. Gamsiz, D.Sc., F.R.S. Prof, WALTER GaArstana, D.Sc. S. F. Harmer, Esq., Sc.D., F.R.S. KE. W. L. Hott, Esq. J. J. Lister, Esq., F.R.S. H. R. Mitt, Esq., D.Sc. P. CHALMERS Mircugtt, Esq., D.Sc., F.R.S. Prof. D'Arcy W. THompson, C.B. Chairman of Council. A. E, Saipuey, Esq., D.Sc., F.R.S. Hon. Treasurer. J. A. TRAvers, Esq. Hon. Secretary. EK. J. ALLEN, Esq., D.Sc. The following Governors are also members of the Council :— G. P. Bipprr, Esq., M.A. G. L. Denman, Esq. (Prime Warden of the Fishmongers’ Company). E. L. Beckwitn, Esq. (Fishmongers’ Company). G. C. Bournsr, Esq., D.Sc. (Oxford University). A. E. Suipuey, Esq., F.R.S. (Cambridge University), Prof. W. A. Hrrpmay, D.Sc., F.R.S. (British Association). Paser Dr. Statement of Receipts and Payments for 5 Sh eh Bi shad To Current Income :— OM Se P rea suievi terran oor eect sie eal ee ak cesar Sau wichs etetes 1,000 0 0 Hishmonpers SOOmpanyac ns. < sles. cetcs -cseeeteanenseion sees 400 0 0 Annual SUUSCrIpP HONS. vc seta. .cecranessce sotencenehonamoamedss SGT 0 Rentrotelablesiee mess -casectecncsterte ce saree een ene es 85 20> =ebsla sano ,, Extraordinary Receipts :— Donations :— Hie ds, BLOWNE, WSs ccc. Jas.;n0raassenesneoices £5 0 0 leteye Dyes JAS IDE fs) oO Wifaosoonotasoseo0odosseces aby WO) 40 0 0 Gloyeay iene ne e(ehe Som ace adseeeen sy Sa hour dgSeac Soren snp sek anc 15 15 0 Hire of Steam Boats :— Reps’ o 41/1112, Teagan can aceon boncnausentaatoada: £600 0 0 SIS POLONG ceca vaste esos eer eene cecaee b0!-70'0 650 0 0 705 15 0 », Balance :— gan from BaMle ss ot oc-urssmue ieccnamneestucncen tian enides 700 0 0 Less :— Caxh at Bank sas. ccs. chiadenwtosmness SAS Onna Cashin hand. atc: icscesensceuveanecsdeie tee 18 19 11 456)" 5 2438 14 6 Notr.—This balance is apportioned as follows :— GeneraleAccount. OVverdrawils sasessscchesencereene ete 396 15 10 Less Repairs and Renewals Account in credit...... ays ee ae £243 14 6 £2,531 2 6 Examined and found correct, (Signed) N. E. Wareruouss, A.C.A. L. W. BYRNE. Hvucu Roserr Miu. 24th June, 1908, a ed [ 32.) the Year ending 31st May, 1908. By Balance from last year, viz. :— Loan from Bank Less Cash at Bank Cashwinvlhan diets. spessns ohn aroha eee 20) 1 4: oe. er eT er er ey », Current Expenditure :— Salaries and Wages— Director Travelling Expenses Library Journal PO eee eee reer en eee renee ee ee see eeeaes tet ensrer esse eessesessesees Buildings and Public Tank Room— Gasweviaters andeCoalls senssccneccccsssaecscck scesnaseaccesns Stocking ‘Tanks, Feeding, etch’ Silt tabaderecncescouces Maintenance and Renewals Less Admission to Tank Room eee eee eee ee Laboratory, Boats, and Sundry Expenses— Stationery, Office Expenses, Printing, etc................ Glass, Chemicals, and Apparatus......... 2st Gis) al BRCSSISAIES) Meaney ne sees eet ne ee ok 52 9 9 Purchase Of: Specimens wisi..secceussseseadsownssasacsereges Maintenance and Renewal of Boats, Nets Gearseteisaseeascsswoseaneeosechas £253) 13) D GCSB ESE Meee te ae ite Sea ony crc te 5p9) 5 Insurance of Steamers— Sno. eeley) (half-year)! Geente.scctssse) ‘ydasor 4g ap ‘suapuagds ; : * ‘ut 90g ‘YASueryT = ‘urUT ¢ 07 F “YIPIAA “Woers pue et =[pAureygq oq ‘2yaugq =| Mopjad qystaq W410 pesto(] “WLIOFISN] W110 IepNoVyUI} pu seToeyU J, | . . . . . . . . . . . . . “UI Oe ‘Yqsue'T \ es ‘uorsurpeyy “oppeyondy wut G.T ‘GIpPIA, ‘OT ‘aeltded yeurusay, ‘aseq ye stosoqoad Jo apis yova uo | e ewpided Jo smoi x1Q “queues yoro uo syods yarp de1yy YI “YsIpped aa eS i WU OST ‘Suey «tu g “ooz qnoytM Apo Jo yIpPIA “LT ‘aeyprded yeurursay, Es “UAISUT[RTY “wsoonu ‘oseq JO apts yoo uo aided yo smox xis puv stosoqord jo qaed yuoay uo seyo | a =poysiqp ‘papwnjwa0ih ) -10qnq JO SMOI XIs YIM stosoqorg “dry oytf-epddiu v WIM Wd yeryUeA ‘SOUT| | 7, OSIOASUBI] UMOIG PUL ANT YITM poyxlVUt JUsUISos Youo ‘udeis ystXois LITo [esIO | * * aepnSuryoarqns °o : : ( MITd [eslop UPIpey{ n ‘UsIsurpeyy ‘0u2.1929 c lu | - =pasiqyn ‘opnonw (4 Saal lf : : : ; ; : : : , ' pT Sepided | - 1 y | jO opis yore | osaaasuesy Jo poursoy gods umosq v YIM MOT[eA YstuseIs ee ) f ‘ srosoq | jeurumey, ‘wu og ‘yySuary «uur | “Joay qnoyyIm Apog Jo YIP ‘AONOGOTIAH snuox) JUAY. Q NOTES ON THE LITTORAL POLYCHATA OF TOR "ydasor 4g ap ‘njsnuaa y f l "ydasor 4g ap ‘nynawyr.l y { “TOIABIE) “VAIN “IVA ‘srpiura “ydaso ¢* ap “nyuso “TRA ‘sipima TT ‘supra ‘ydasor 4g op ‘vaund y "pd ‘nynquay y "aqua ‘so1sv0.4opUL “Bain SOM aly woods pap1oda.t JON x : : "uur gg “yysuery “py ‘aypided [eurutay, “prey yo qavd puv safe oyy uoeajoq AvM-y[ey epoezuey porreduy “payjods SJUIIFes SUTUIMEI “MMOIG WOJTUN syUEWISes puodes puL qsIT : : ‘mw gt ‘yysuey = *g “eyided jeurmaay, “yuewSes yore Jo a1j7Ue9 ayy UO syed oo1Y4 OFUT U@eYorq oUIT Yrep vB YQLA ‘uaery , : ; ; "uur og ‘YySuey «0g ‘e[pided jeuruaay, ‘JUoUIsos OYJ JO apIs YoRa UO OUI, yep ve puL ‘ouTT [eaquOD OY} JO OpIs Yows UO soul] 4o[OIA [RUIPNISUoT oy YL ‘Moa 5 a c ; : : : . * “UIUT 09 ‘y4Suery ‘81 ‘e[pided [eurunay, “yuourZas oy} Jo opts yoRo uo savq qorpeaed OM} PUB JUAIUSes ove Jo afpprux ey} uo yods yaep v YAIA ‘MOTTA : : ‘WU Og “YysueTT “1g 0) FT “eeppided peurmaey, ‘usaaxy : : ; : ; ; : ‘ ; as uur g ‘yysueT 'g ‘eypided peurmiey, ‘eepided yesoyey qnoyqim stosoq “Old “8IY oy ydooxe quouiSes yora uo yods uMoIq & YITM UeaTd ‘uM 2 “Yysuey “py ‘eypided peurmuay, “oad ysryurg WU Og “YySueTy “gp ‘eeppided peurmuey, “uoorS [[Np 10 uMOAg ‘VITVING snue+) : * — snovoripoy 4ou T11d aepnoequey yo aed poses Jo Wao peIquoA ‘SAUUINOUaL J snuasqns =sse00id snoaovitfoyoqey] -O99UL] SUOCT & SuTUTIO; TIT) aeyNoeyuey jo ared poses at] JO LAAT [Vayu A “yutod v 0} Sursedey a}epoooury * 11119 [RSIO, ON THE LITTORAL POLYCHATA OF TORQUAY. S NOTE 356 ‘Bale YSI}Ig oy} Wo paps10del JON , “ySue'y “wnjoyn = savy “wnsoyof ; - " waoytun T10 [esIog ‘apts youo uo dey v yy Aplorseysod paystuiny prey ‘WATIAHAOLON snuoy ‘ydasop 4g ep ‘wupasndnyp : : 2 : ‘mur QOL ‘Yysuey “pT ‘eettded =ysoyupoyy ‘npnpundrs} jeumay, “queues yove Jo yorq ay} uo sjods youlq Io usaIs snonotdsuo 901], aa vaarey Um : ‘WUE Zl ‘YSueT ‘WU T.0 “t4aTo [esdOp Jo YySUeT] “gz ‘stosoqoad jo eypided ; ; : poayutod PASTY PS ) reuruay, “youd oy} JO o[pprux ay} UT eUlT [UIPNILsUO] Users w YITA “YsTUMOIE ‘oqvBUo[a [BAO LITO [es10(] “ILOJSUYO F “ngMdUAA2 , ed hg pi gb tat ‘yaSuer] “yaey ayy JO aseq oY Ae apis YoRe Suoye oul] Yep & YIM portno[oo-Mvsys “LOTAGAL) ‘STUNUULOD “ABA ee 1 fi k : 3 Cet : told iw o! J AG fs A 0 2 oy 16 ~ Cpaysuyy nouanbuvs y (wprungt) — § WI Og ‘YASUET ‘sjods ouY YATA\ petoAod ‘UMOAG YSIAaTy) 4 aYZ JO Bopa AOTIA}SO oy} UO epoejuey poareduy) ; * pray Jo WuOdy pue saxo usemyoq ABA TOSS 10 EE ule 3 ; ; : ‘ “TUT OG 0} OS ‘UISUeTT “WALOIG AvETD) -J[ey epoejuey porreduy, ‘ydasoe 49 ap ‘suapuads y ‘ayBp109 (- : : ; : : ; : : uu Qe] “query LI1d [BSLO(] aqua ‘nwafyound Q iS : J -igmo7 91 UeUA aasuoT YonuT ssevo1d snoaeSsyes jo quiz aodd {3 if l I =nseyuo, ‘vsopngau \ ; * sade oy} Jo JUOTS ‘sada ay} JO JUOI UT peat, oy UO syods UMOIG OALy YI ‘May PUL apIPT ATA TO TTA aur] UL apoeyue, patiedu yy), ‘ydasop 4S ap Svsourhrqne - UU PL ‘YIBuey] “Mato pestop pad yyiar ‘uMorg [Up Apog . . . . . . . . . “UU OSI ‘yysuoe'y] ‘LLI1O [WAJUGA PUL [BsLOp UO sjods UMOIG ‘UsEIS pu MOTI JULIA . = poysaiTy ‘wauinbwns (pprunyy ) B ILM payIVUI SI9YIO oY JO TOS PU JUOUIDES ISI “UMOI OTe *panuijuogo—VITVING SONA) ON THE LITTORAL POLYCHATA OF TORQUAY. S NOTE “AULBIARG ‘pyoonf (swidaprasany) siawa ny “MAABU [VI ‘YDLOLLL (DIYPLDLT) $V9ba NT STG Wee 10) “Lopoaiswaayp (agsupazy) siasa Ny TT “worbnpad sata xy "S1Bg ‘sual (04277) svaa nT “LOJSTATPO f* ‘pirss~ihuo) sraaun gy ‘ydaso pr ‘ag ap ‘yup, srasanwojda] ‘pdQ “wppharwna srasauUosoryy e ‘snadto ; “ULUT OGT ‘YQSueTyT = *qeao \ yesiop | pe jo [BSUSWWOZ) “WNsIOP UO spud oqTY A OAT, jo asuq qe durnyy | * “um og] ‘yysuery “Apoq jo \ ‘snonotdsuoo lrva3 sane | worjaod TOWe4sod UT 9YTT-sn4i19 pre qooy Ut a a soles eno) £10 tuntpodojou Jo aqoy aadd gq | spuryy 3y¢ aes peat sey 70 STOSO ore ; ; ; qred e. Onions mT ; uur gg ‘YysueT = “qratds sonerie ame a > yo 41ed UL padNO[Oo-UMRT sovJINS [es1op Hee peerene a le Be | roddn "[BOLUOD [[R jo qied quorq = “Tyeuts Ara saqory a estop jo | oe url ‘1939504 Ua] “4aey} UL} AasU0T You TWATO Riseise ee “ | vorjeurstad eAtusopukg *0z 1 i As af . AL ti A : * —- BPBOTNS oJLVISW “61 — sue soi a out ge 4 : Byepnommmeqns “f ‘eT i a ; neta Rar . . TUOTIVUT I) | 500 ae : ; BYBACOXO BUTT “OT 4 ie oo ei * snoqjta af ‘GL Pas 2p vs te te te ac fe 2 : * SI[IWUIS UINIOIT[e “PL : 5 ; ve a a a + ae stavjnoiedo ueqoadinbyy “eT. 300 7 age i aie fe vo ee i * snyeorus shure[yO ‘ZT si sss nod wee oo un vee a : 0 : Teniq 19}0eq "TTL 306 500 ae oo oo ae 4 vulpoaseyd e][as[OA “OL eee eee al eee tee ay . . enbitqo ce 6 4 a : site + oo ve ” p 4 s : eso[Upou voIV *“g fon Bc ne : a . i “ . a A * suroutfodTS staautfoh[) *L 5c ae ‘ : “ : oo 0 0 + : * eQnUrUuL og 9 “s as igs vee 4 vee an 7 * eye stisdoury *¢ 200 te cn 4 ’ oo ze + : umiddryda vrmony ‘Ff ‘i ae di0 ooo ” nue + 9 ; epi = SS 4s Boe ve ae ” , : : “0 + 0 : * — Byeorns B[MONNT °*Z “epodfoajoq i : 600 tes + + etmoydorpse viuauoredoyy *T ‘BIneulrydMy Satogddg HSILIUg GIP 9FG OFT OFS Lad 18 601 60T Gh Gh ; SULOTTFV 18T 08 181 08 /TT 8 /8T 8 ITS ob BT od 19% ob 198 ob 188 09 $3 09 "M ‘opnyisuor] 1), 8F 14 8h | 101 8F 14 8h | 198 04h | 19F Lb | (Sh olb | i8Polh | 170 8h | 7196 OF ‘N ‘opnqiqeT IlIx ITX Ix XI IIA IA A AI II I ‘ON NOLLVAG THE MOLLUSCA COLLECTED BY THE “HUXLEY” FROM THE 390 1S 8 14 8F + + " + : a i ; 3 + Fs Ke +- . eee - re s : aS ee oe es ze Ee 9FL OF PPP 18 601 601 11T 8 1§T 8 Wises 16 oh 19F od 196 oh /OL 8F 11, 8F 196 oLF 19% oL¥ (SP LF 18 LP IX XI- | sIiA, | — 1A A AI 11X ‘panuyjuoo— FNOOO AHHL HOIHM LV Gh SNOILVIS HHL ANV 182 9 /¥G SPF GL 183 9 196 SP ++ ++ t+eettttt+++4+4¢4t suloadg HSILIU : ; ¢ : BINSSY VINUIDIVUY “GE : : * BUIyoRoU B[[aInjoung ‘BE ‘epodorjsBy wunterntatoued ss “LE 5 stjeqyue UINIpeJuaq? “9g “epodoydsag . . . . . eqyino “ec “Ge : p * eyeptdsno itd ‘hE 0 : : * Byeraoiqqe viiepidsng “eg soovikded vloeiyy, "2g BOIBIALOU BISUOATT “TE : : : * srayeatnbaur wlopueg ‘0g . . . . . BOIYOIE BAVOIXBG “GZ BYL[NYSOO Tet) “BZ : : * WUNOTSIALOU WINIPIBOTAB] “1Z : ; : : ULNUITULU WUNTpPley “9Z . . . . BOO SED asec “eyeao ‘¢ ‘PZ BUIStO SHUAA “EZ eyepun sisdoutony “ZZ “‘panuywoo—epodkoa]9g SuULOYyye] “M ‘opnyisuory "N ‘opnqiyey ' ‘ON NOMYV.Lg ‘SHIOHdS AHO LSTT 391 NORTH SIDE OF THE BAY OF BISCAY, IN AUGUST, 1906. rt++4++ ++ sony +++ D+ cartacky +++++ i++ t+H+ i++ ++ tt¢4 i+ 4444+ D+ itt P+++4+4+44+ ‘ds oj0q] “a4 “atqouvIqIpuN : ‘ds snyouriqoinetg “p, . . Bxo]JUl “ce ey) * —- esoutdsi1q BIUlpoaRD °Z/ : * ezyeptuerdd og “TZ * gniieust] tapueydeog ‘os : * BVRTNYSOO SIYORUW *69 : snyeouut uoydory, “99 * [parvyol xemmulopnesg */9 SISUATOIUIEG SHsnjoutoong “99 ce ee * — STULIOJIsny “a9 snurishargel as ee "F9 * snqiny sf as!) * snnbutdoad (stq1ouoydrg) e AS) . * —- sI[lovls snsnjouoqzl1y, “19 : * —-TaT@p snsewory ‘og . . ‘ds ce "6S * wnyepun wnuDong ‘g¢ : * — BYIJSOA BI[TAIOT, "7G * —- STUNTHULOD BTTEITIIN, “9G ee ~ Tpreyour ** “gg * euedjosey “ ‘pg : : SNIYIL[O BLOG “EG : " BaqzURsIS vijouRy “ZG * enordsied viaeyjoutey ‘TG ONE] O AC ON amen) Bee TO), dake (( OG) OC "GP Lleple a ED eet "OF 19480 ( 6“ ) « ha VPIpxOs (VIYVUNT) VOIYRN “OF snolivsuny snyndeg ef “ce wnyepnuels “PP sleet] Tur S ‘SP eiyedooyo 2 ‘OP * TWN[Nsaqo VULOFSOT][VO “LF VIVIABSIYNUL VINUISICUUY “OP “panurjuor—Bpodo14sBy Oo Jo) bo = The Brachiopoda collected by the “Huxley” from the North Side of the Bay of Biscay, in August, 1906. By Alexander Reynell. OF the three species of Brachiopoda found, two, Magellania cranvwm and M. septigera, are found in the British list. The third species, Mihifeldiva truncata, has not, as far as I can discover, previously been recorded’ from so high a latitude, Turton’s Torbay locality being very doubtful. BRACHIOPODA. ARTICULATA. TEREBRATULID4. MAGELLANIA, Bayle. (1) Magellania cranium, Miiller. Terebratula cranium, Miller, 1776. Zool. Dan. Prodr., p. 249. Anomia cranium, Gmelin, 1789. Syst. Nat., édit. xiii, p. 3347. Waldheimia cranium, Reeve, 1860. Conch. Icon., pl. 11, fig. 6. Magellania (Macandrevia) cranium, P. Fischer et C&hlert, 1891. Trav. and Talis. Expedit., Brach., p. 73, pl. v, figs. 10a—10s. Distributed from Greenland and Norway to the south-west of France, according to Jeffreys. A. Adams records it from Northern Asia and Japan. Mons. Dautzenberg kindly identified this species. Station V. 109 fathoms. One living. » XII. 246 fathoms. One living. (2) Magellania septigera, Lovén. Terebratula septigera, Lovén, 1846. Index Moll. Scand., p. 29. Waldheimia septigera, Davidson, 1855. Ann. and Mag. Nat. Hist. [IT], vol. xvi, 1855. Terebratula septata, Jeffreys, 1878. Proc. Zool. Soc., London, p. 407, jolBee.c.abb lay Wie Ue THE BRACHIOPODA COLLECTED BY THE ‘“‘ HUXLEY.” 393 There seems to be some doubt as to whether this species is the same as the Terebratula septata of Philippi. Both Jeffreys and Locard are of the opinion that it is, but Fischer and Ghlert do not even mention Philippi’s name. I, under the circumstances, think it the wisest plan to follow the latter authorities. This species seems to be distributed in the eastern part of the North Atlantic, from Norway and the Hebrides and Shetland Islands to the West Coast of Africa and the Canary Islands. Station XI. 146 fathoms. One small, living. nm XIII. 412 fathoms. Eleven living. MUHLFELDTIA, Bayle. Mihlfeldtia truncata (Linné). Anomia truncata, Linné, 1767. Syst. Nat., édit. xii, p. 1152, No. 229. Terebratula truncata, Philippi, 1836. Enum. Moll. Sicil., I, p. 95, pl. vi, fig. 12. Mihlfeldtia truncata, P. Fischer and D. P. Gthlert, 1891. Trav. et Talis. Brachiopoda, p. 80, pl. vii, figs. 1la—11¢. This species is recorded as being very common in the Mediterranean, and has been found in the Bay of Biscay, at many stations off Cape Finisterre, the North of Spain, and has been dredged off the Morocco coast, and the Canary Isles. Turton’s record of a specimen from Torbay is generally considered doubtful, as far as being a proof of its living in the British area is concerned. Station VII. 144 fathoms. Three living, BIBLIOGRAPHY. Fischer, P., and GEhlert, D. P.—Brachiopodes de l’Atlantique Nord, 1892. Résultats des Campagnes Scientifiques accomplies sur son Yacht par Albert Tet Prince de Monaco. Jeffreys, J. Gwyn.—On the Mollusca procured during the Lightning and Porcupine Expedition, 1868-70. Part I, Proc. Zool. Soc., Lond., 1878. Locard, A.—Brachiopods. Résultats Scientifiques de la Campagne du Caudan dans le Golfe de Gascogne, August-September, 1895, 1896. Many Brachiopods are, of course, included in the older works dealing with the Mollusca as detailed in the bibliography of that group on pages 387 and 388. 394 | Mackerel and Sunshine. By E. J. Allen, D.Sc., Director of the Marine Biological Association. With Figs. 1-5 in the Text and Tables I.-VII. at the end. In his paper on “Plankton Studies in Relation to the Western Mackerel Fishery,” in the last number of this Journal (Vol. VIII, p. 269), G. E. Bullen shows that for the years 1903-1907 there appears to be a correlation between the number of mackerel taken during May and the amount of Copepod plankton, upon which the mackerel feed, taken in the neighbourhood of the mackerel fishing grounds during the same month. It was clearly worth while, therefore, to consider what conditions favour the production of an abundant supply of Copepods in the fishing area, since it appears to be this supply of food which attracts the mackerel into that area, or at any rate into its surface waters. The hydrographical investigations carried out at the mouth of the English Channel have rendered it probable that the movement of the water there is comparatively slow. It may therefore be assumed that on the mackerel grounds to the westward of the Cornish coast the water which is present at any particular time has not recently moved into the district from any very remote region, and, treating the matter broadly, has been subjected for some time to the general climatic conditions of the neighbourhood. The question then suggests itself, can the differences which occur from year to year in the abundance of the Copepods be referred in any way to such climatic conditions? If such a connection exists it will probably be not direct, but indirect, through the action of the climatic conditions on the food of the Copepods. The food of Copepods seems to be largely the vegetable organisms of the plankton, chiefly diatoms and Peridinide,* * This has long been recognised in a general way, but useful direct evidence of it has recently been brought forward by W. J. Dakin. Notes on the Alimentary Canal and Food of the Copepoda. Internat. Revue der gesam. Hydrobiologie wu. Hydrographie, 1., 1908. MACKEREL AND SUNSHINE. 395 though even if a considerable proportion of it were found to consist of minute animal organisms, these in their turn would feed upon the phytoplankton. It is therefore to the conditions which favour the production of phytoplankton, the fundamental food supply, that we must turn. The three most obvious matters to be considered in connection with the production of this vegetable plankton are: (1) the composition of the sea-water itself, (2) the temperature, and (3) the amount of light which is available for the production of plant life. With regard to the composition of the sea-water itself, the only information available refers to its salinity, and up to the present it has not been possible to show any simple relation between changes in salinity and changes in the vegetable or animal production in the area under consideration. The same is true of temperature, though this will be considered in more detail below. It is the object of the present paper to call attention to what appears to be evidence of the influence of the third factor, the intensity of light. Experiments on the cultivation of marine plankton diatoms in the laboratory, upon which I had been engaged, had drawn my attention to the great importance to be attached to the intensity of the light to which the diatoms were exposed. It therefore occurred to me that a. special abundance of Copepods during the month of May in any year might be due to a special amount of sunshine during the earlier months of the year, which would increase the amount of phytoplankton, the Copepod food. An attempt was therefore made to correlate the average quantity of mackerel per boat taken in May with the number of hours of bright sunshine recorded during the first quarter of the year. The official statistics of mackerel landed are not very satisfactory for such a purpose, since they give only the total quantities of fish and give no information as to the number of vessels from which the fish are obtained. In making use of them, therefore, one must bear in mind that the number of vessels to which the figures relate varies from year to year, although the amount of this variation over a small number of consecutive years will not generally be very large. In order to get figures of a more definite character, I applied to Messrs. Peacock & Co., of Lowestoft, who have had vessels engaged in the western mackerel fishery for many years. Messrs. Peacock were good enough to furnish me with a series of figures giving the number of hundreds of mackerel landed each month from February to June, at Newlyn and Milford,* by three of their steam drifters, for each of the * These vessels landed fish only at Newlyn and Milford, so that, by combining the figures for the two ports, we get the total number of fish taken by each boat from the western fishing grounds, NEW SERIES.—VOL. VIII. NO. 4. 2E HRS. SUNf 275 250 225 200 175 150 396 MACKEREL AND SUNSHINE. years 1902-1908, as well as similar figures for three sailing drifters. These figures are given in Tables I. and II. Messrs. Peacock’s figures show that by far the largest quantities of mackerel are landed in the month of May, and that, as in the case of the official statistics (cf. Bullen, Joc. cit., p. 277), the figures representing the May landings dominate the curve representing the total landings from the spring fishing. Moreover, it is practically certain that the vessels fished throughout May, whereas for the other months, except, perhaps, April, one has not generally any definite knowledge as to when they began or ended their fishing. In the diagram below (Fig. 1) the average number of mackerel per HUNDREDS OF MACKEREL IN MAY 700 aE 600 4 \ \ EN if / \ nN 7 \ 500 Mh \\ : Th \ 4 \ AVERAGE / + AVERAGE 275 = ji 455 No, ve 400 NAG / ANN / ONG / 4X9 / eS VA N ACr se ee /; 300 Y = 200 1902 1905 1904 1905 1906 907 19038 Fic. 1.—The dotted line indicates the average number of hours of bright sunshine re- corded for the months of February and March, in each of the years 1902-1908, at the meteorological stations at Plymouth, Falmor *h, and Scilly. The continuous line indicates the average number of “hundreds” (120 fish) of mackerel per boat landed at Newlyn and Milford in the month of May of the same years 1902-1908, by three steam drifters belonging to Messrs. Peacock & Co., of Lowestoft. boat in “ hundreds” (each “hundred” really means 120 fish) landed in May by Messrs. Peacock’s three steam drifters is represented by the continuous line, whilst the number of hours bright sunshine during February and March is represented by the dotted line. The sunshine figures were obtained by taking the average of the number of hours —_ oe MACKEREL AND SUNSHINE. 397 recorded at the three meteorological stations, Plymouth, Falmouth, and Scilly. Although the extreme closeness of the agreement between the two curves may be due to chance, it seems scarcely possible to doubt that they indicate a fundamental correlation between the abundance of mackerel in May and the amount of bright sunshine during the earlier months of the year. The sunshine curve, it should be added, has practically the same shape, whether it is taken for the three stations chosen, or for the whole south-western district of England, which includes inland stations, or for the south-west of England and south Ireland combined. The figures on which the sunshine curve is based will be found in Table III. In Fig. 2 the continuous line gives the total number of cwts. of mackerel landed on the south and west coasts of England and Wales in May* for each of the years from 1886-1908, as given by the official statistics of the Board of Trade and Board of Agriculture and Fisheries (see Table IV.), whilst the dotted line gives the average number of hours bright sunshine recorded for the south-west of England and south Ireland for the first quarter of the year (Jan.— March), as given in the reports of the Meteorological Office (see Table V.). As already pointed out, the official figures of mackerel landed take no account of the number of boats fishing, and those taken during the first four or five years are known to be very imperfect and should therefore be neglected. It is practically certain that the fishing power has increased during the years for which the records are given, more especially since the introduction of steam drifting about 1902. Comparing the two curves in Fig. 2 generally, and bearing in mind the above limitations, there is, I think, sufficient similarity in the way in which they rise and fall together to justify us in regarding them as in no way contradicting the very definite agreement shown between Messrs. Peacock’s figures and the sunshine curve as seen in Fig. 1. Considering in wore detail the years 1902-1908, it will be seen that the most striking difference between the curve given by the official figures and that representing the averages for Messrs. Peacock’s boats is the great drop wh’th the official figures show in 1906. A similar though less marked drop in 1906 is also shown by the curve given in Fig. 3, which represents the average number of “ hundreds” of mackerel landed by Messrs. Peacock’s three sailing drifters. A reference to the figure given by Bullen (loc. cit., p. 279, Fig. 1) also shows a minimum in 1906 for the Copepods taken at the International Stations E.5. and E.6. The high figure for 1906 given by the three steam drifters, although it agrees with the high February and March sunshine for that * Most of the fish are landed at Newlyn and Milford Haven. *(SO19SIFRIG [PIOYO) SOGI-H88I Sivek ayy Jo Yous roy ‘Av Jo YWOU 943 Ur ‘sale A\ pue PUL/SUG JO S{svog 4ysoAy PUB YINOG oY} UO pepue] se paplOdad [aloYOVUL Jo S}YSIoMparpuny Jo loqwuNuU ot} sayRoIpUt UT, snonUTyUOD auL "YINOG puLzpaly pUe “SITeAL “G PUY “A'S PUL[SUG spOLIySICT SIO [ROIBo[o1OI}oT OY} LOJ “QOG{-98gT Sivek at} Jo yous toy (Youryy 0} Arenuvy) wok oy Jo toqrenb qsay oy} 10J poplooat oUTYSIMS 4YFIAQ JO SOY JO TaquUINU oBvAOAV O44 SazROIpUT OUI, poyjop wuL—s ‘ol ~~ 20q 20m 90m Sms vO! = Orme c0r = 107 OOO OO, = 26, 26. 1960 SOul pon SOlue=ZcOnlom 0bn mmGQuEEog, eons} 000'09 og 000'00} 002e 00001 022 00002) Ove 000'022 092 000'092 ogz 000'00€ oo¢ 000 0LE oz . JNIHSNNS oogogrs LHDIUE Al JyINOVW 40 SUNOH MACKEREL AND SUNSHINE. 399 year, does not therefore agree with the official figures for mackerel, with the catches of the three sailing drifters, nor with the figure taken to represent the Copepods. Any explanation of this discrepancy can only be of a speculative kind, but it is probable that the steam drifters fished much further west of the Scillies than the sailing drifters would go, or than the International Stations are situated. If this is the explanation of the difference shown, it would seem to suggest that in May, 1906, there was some local factor at work on the grounds nearer the shore which did not operate on those which were more distant. HUNDREDS or MACKEREL 400 200 cre Vlas S$ 100 ————t-—___--__! 1902 1905 1904 1905 1906 1907 Fic. 3.—Curve indicating the average number of ‘‘ hundreds” (120 fish) of mackerel per boat, landed at Newlyn and Milford, in the month of May of the years 1902- 1907, by three sailing drifters belonging to Messrs. Peacock & Co., of Lowestoft. Before leaving the question of sunshine it should be stated that curves representing the bright sunshine in the months of April and May have not shown any kind of correlation with the quantities of mackerel taken. In order to ascertain whether the temperature of the water during the fishing months in the different years bore any relation to the takes of mackerel, and to meet the suggestion that the effect of the bright sunshine might have been simply to increase that temperature, a series of curves have been drawn showing the average temperature of the surface water in February, March, April, and May for each of the years 1902-1908 in the area between 48° and 50° North Latitude and 4° and 10° West Longitude. The temperatures given in Table VI., and 400 MACKEREL AND SUNSHINE. represented in Fig. 4, are the means of the six temperature averages given for this area on the Monthly Pilot Charts of the North Atlantic, issued by the Meteorological Office in London. For comparison with these, Table VII., and Fig. 5 give the mean temperatures at the surface and at 10 meters (5 fathoms) depth found at Stations E.5. and E.6. on the International Cruises carried out in May in each of the years 1903-8. It will be seen that the two curves follow; the same general course. The outstanding feature of these temperature curves is the occurrence of two very marked maxima in 1903 and 1905. On 8° 1902 1903 1904 1905 i906 1907 1905 Fic. 4.—Curves showing the mean surface temperature of the sea in degrees Centigrade in the area between Lat. 48° and 52° N., and Long. 4° and 10° W., as given on the Monthly Pilot Charts of the Meteorological Office for the months of February, March, April, and May, in the years 1902-1908. comparing the curves with the curves representing the catches of mackerel, either with that given by Messrs., Peacock’s figures, or by the official figures, no relation between the two can be traced. Whilst the 1905 temperature maximum agrees with the maximum total catch of mackerel as shown by the official statistics and the high average catch shown by Messrs. Peacock’s figures, the temperature maximum of 1903 is accompanied by low catches of mackerel. The other parts of the curves also give no indication of any close connection between the surface sea temperatures and the mackerel catches. MACKEREL AND SUNSHINE. 401 I have to thank Mr. G. E. Bullen for assistance in plotting the early curves which rendered the relation between sunshine and mackerel probable, though I am myself entirely responsible for the accuracy of the curves and figures as given in this paper. Mr. D. J. Matthews has also helped me in various ways. My thanks are especially due to Messrs. Peacock & Co., of Lowestoft, for the very great trouble they have taken in supplying the figures showing the numbers of mackerel caught by their vessels and for allowing them to be used. Without their ready co-operation this paper could not have been written. 1903 1904 1905 1906 1907 1908 Fie. 5.—Curves showing the means of the temperatures, in degrees Centigrade, recorded at Stations E.5 and E.6 at the surface (continuous line) and at 10 meters (dotted line), on the International Investigation Cruisés in the month of May, for the years 1903-1908. 402 MACKEREL AND SUNSHINE. TABLE IL Table showing the number of “hundreds” of Mackerel landed by three STEAM DRIFTERS at Newlyn and Milford Haven for the years 1902-8, from figures supplied by Messrs. Peacock & Co., of Lowestoft. LANDED AT NEWLYN. | LANDED AT MILFORD. lvaeaber Gf | ‘hundreds’ —_—_—— aX —_—_——— | per boat landed at Steam Steam Steam Steam Steam Steam Newlyn drifter drifter drifter drifter drifter drifter and A, B. C. A. B. C. Milford. 1902. Has. Has. Hds. | Has. Has, Has. Has. March . : = 2224 ie Py les nee eye le ASO Tillln es -| 1032 2632 1344 os cs = 201 May . Hh 4904, 263 1134 ae ee ae 289 Jie |e : 287 2894 aes = <= == 288 1903. March . .| 2474 1274 4094 = = = 261 April. -| 1204 1403 202 == — 244 162 May, cs 097 .)| AS98482 O18 TO = 603 268 Afeteiy. “ee .| 1174 574 47 _ pas = 74 1904, March . .| 3003 3474 2374 _ — at ile eeeonl Aerilees) Seis ores! ses 28) ea ah 34 225 May . ., 2932 298 1974 = —_ = 261 aun) -| 277% 143 Sy fall) at — — 210 1995. February .) — 19% -- 96 494 2 ah 59 March . », 1204 182 374} 984 874 25 | 296 PAT ae -| 2852 — 2914 — 4292 — 319 Manvel 3) byt 37 4704 — 3782 — | 490 Junewe : 474 — == = 77 ay 47 1906. February any oe — = 4 tls bs ae March . Syl aeeaidia 16 124 4 111? 123 61 April . .| 1103 62 1294 — 834 — 125 May . alk 269 767 7084 — — — 581 June -| 29 — 21 — — — 25 1907. March . 1604 94 484 — 324 — 83 April 1054 3204 105} — 44 _ 178 May 457 869 5843 — — — 637 June . fo = aes = es = ae 1908. [ March . .!| 109% 664" 37+ — — — 71 April .| 8632 266 3264 —_ —_ = 319 May . .| 418 6162 23729 = _ = 517tt June . fo — “= a — — _— * Steam drifter B is not the same vessel in 1908 as in previous years. + Commenced March 17th. {] Finished May 19th. tt Average for vessels A and B, MACKEREL AND SUNSHINE. TABLE 1G 403 Table showing the number of “hundreds” of Mackerel landed by three SAILING DRIFTERS at Newlyn and Milford Haven for the years 1902-7, from figures supplied by Messrs. Peacock & Co., of Lowestoft. 1902. March April May June 1903. March . April May June 1904. March . April May June 1905. March April May June 1906. March . April May June 1907, March . April May June LANDED AT NEWLYN. LANDED AT MILFORD. |wavCpe® oe ' ; ‘hundreds’ | nem per boat | landed at Sailing Sailing Sailing Sailing Sailing Sailing Newlyn drifter drifter drifter drifter drifter drifter and in B. : A. (oF Milford. Has. Has. Hds. Has. Hds. Hds. Hds. 14 9 = = — ss 5 574 241 1294 = — _ 144 = 150 215% = == = 183 aes a 113 ae abs we 113 1} 534 = ass = = 27 833 160 774 — — — 107 93} aa 1234 ae! 202 = 139 88 57% =: 1663 _ = oe 104 = 31 102 = 594 ee Rl 19 — 474 — 86 sant ati | Ol 187 107 1434 = 35 A LOE 113 814 1083 — — — | 99 | = = 1624 am 240 =e Aa PaO 423 a 2374 == 2653 mA Sel pas) 2594 250 4572 == 70 Veo AY Wo eaee 524 at = se = Es hao en 192 = 64 es 124 EN ale 2262 a 1574 — 151 — 178 90 — 1114 — 443 — Pee Zale = 104 = me = = ak» 104 56} 12 _ = 1534 =|) a6 2404 64 1483 = 804 cy Te peg = 58 260 = 2664 ne 292 404 MACKEREL AND SUNSHINE. TABLE III. Table showing the average number of hours of BRIGHT SUNSHINE recorded at the three Meteorological Stations, Plymouth, Falmouth, and Scilly, in January, February, and March of the years 1902-8. 1902. | January. | February., March. foe pes Plymouth . .| -45°6 92°5 | 10874 SOEUArY ier Ralmouthy 2)! .).049-3' || "87-0 Jiwiag ae | een ee Scilly 5 FS URE SG couall Oe ral bolo peAverages (0) 0074 ili S0r7 Dit 208 °4 1903. Plymouth . .| 38°6 593 | 110°8 Falmouth . .| 55°3 | 63°3 126°7 Scilly : oH eer salar 50°2 129°6 De PAveragey lacoN op ON On eles: —180°0 1904. Plymouth . .| 42°0 52-1 121°5 Falmouth . af) 230 57°7 104°7 Scilly NOG Bats PSP ES Average .| 46:5 | 55-1 | 116-5 171°6 1905. i Plymouth . | Osa all ee SiO 136°6 Falmouth . VwGonln ie) S820 Loan Scilly : oH GLc7 oa. S1sO- | AAG Sie Average .| 65-4 | 83:6 | 140-2 —-2288 1906. | Plymouth . ai OG a VOGr2, jl4259 Falmouth . -| 64:6 | 110°7 164°8 Scilly : Bi Cee ile aK ene" |p alse} Average .| 69°8 | 102°9 | 154-0 256°9 1907. Plymouth . : 75 91 186 Falmouth . : Et 7s 178 Scilly Seale N66M, Ss OS 186 Average . 72 79 183 262 1908. | - Plymouth . é 72 67 147 Falmouth . : 49 74 153 Scilly : [duu 61 158 Average . 59 67 153 220 MACKEREL AND SUNSHINE. 405 TABLE IV. Table showing the number of hundredweights of MACKEREL landed at Ports on the South and West Coasts of England and Wales in the month of May for the years 1886-1908, compiled from official statistics of the Board of Trade and Board of Agriculture and Fisheries. May. | May. Year. No of cwts. Mackerel. Year, No. of cwts. Mackerel. 1886 a 63,338 | 1898 fee 146,769 1887 Ass (lsiys 1899 iat 207,962 1888 38 139,739 1900 se 138,723 1889 sis 173,828 1901 tae 169,020 1890 ae 280,444 1902 att 169,857 1891 Ss 127,148 | 1903 wee 152,753 1892 ee 127,183 | 1904 ee 199,884 1893 a 105,754 | 1905 a 378,157 1894 oe 139,384 1906 a 108,273 1895 sie 135,238 1907 ons 222,151 1896 sate 119,328 | 1908 vee 108,144 1897 335 193,769 TABLE V. Table showing the Number of Hours of BricgHT SUNSHINE recorded over Hngland S.W. and S. Wales and Ireland S. for the first Quarter of the years 1886-1908. From the records of the Meteorological Office. England 8S. W. and 8, Wales. Ireland 8S. Mean. Year. Hours. Hours. Hours. SSC. oe) eee 174 2038 188 IRSSGan wipe oes 314 309 312 ASSO wtyetccs: 240 260 250 SSO ie tee 22 243 235 SOOM ences 239 247 243 cho Whee ee 300 300 300 ESO DBF) Medes 305 257 281 ES OSs ryuen Ye ke 285 244 264 1894 aie 330 293 312 SOB ots | Taree 292 260 276 LSOGP as. eos ie 195 190 192 TSO fms cae veces 215 237 226 SOS) Maes Wieeeses 260 255 257 SOOM Ny ar 304 286 295 LSOOW IS Me reas 234 256 245 TO OH he! FPN hese 240 238 239 MOO 2 ih ates ee 217 215 216 UGOS ae sane: 205 201 203 NGOS et ees 207 193 200 ESOS 6 Meakeckae 272 268 270 UGOG 9 ieee 286 250 268 LOO. Wea eee 315 256 286 S085 7 eeeee 246 229 238 406 -MACKEREL AND SUNSHINE. TABLE V1. Table showing the average surface temperature in degrees Centi- grade of the Area between 48° and 52° North Latitude and 4° and 10° West Longitude from February to May, as given on the Monthly Pilot Charts of the Meteorological Office. Each temperature given is the antes of six means printed on the charts. 1902, 1903, 1904. 1905, 1906. 1907. 1908. Gute not Si ORO Ol 9°6 9°3 8-4 9°4 March ee 9:2 oe) 8°9 7 9°2 9°0 9°0 April Beis: EE yA} 9°6 9°9 9°3 9°6 8°9 May spo OSA Te NOS Abe Oe Oa} aha) TABLE VII. May HyproGRAPHIC CRUISES. TEMPERATURES (C°?) AT STATIONS E.5 AND E.6. Surface. 10 meters. B.B. E6 | Mean. | E.5. E.6. | Mean. 1903. 5 || also 10°20 | 10°64 || 11:02 | 10°19 | 10°60 1904. 5 9565) sie) eS ON 946 960 915 | 9°37 WENO} o|| Jabs) MOSS See Aes lel in eal LOS A098 1906. Py LOGO OS 9°92 | 10°08 9562) 982 UGO c Sl LOGO 1 92797) Or o4 ae 10-68 9°338* | 9:98 SOS. .| 10°69 9:91 | 10:30) 4) 10°69 9°85 | 10°27 Station E.5 is situated in Lat. 49° 6’ N., Long. 6° 32’ W.; i.e. about 50 miles to the southward of the Scilly Isles. Station E.6 is situated in Lat. 50° 24’ N., Long. 6° 5’ W.; i.e. about 30 miles to the northward of the Scilly Isles. The Temperature records are taken from the Bulletin des résultats acquis pendant les crowsteres iit aera Maas 1902 onwards. “2 shitle oe BOG We 50° 35’ N. Lat., 6° 14’ W. Long., 89 m., worked for E.6. (about 11 rites further north). ’ Probable surface temp. at E.6. would be 0°4° lower. [ 407 ] The Decapoda collected by the “ Huxley” from the North Side of the Bay of Biscay in August, 1906. By Stanley Kemp, B.A. THE collection of Decapoda made by the Muzley during her short cruise on the north side of the Bay of Biscay is an extensive one; it comprises no less than forty-nine species—a number which speaks well for the efficiency of the gear employed. Although, as might be expected, the majority of the species obtained are well-known members of the N.E. Atlantic fauna, the material presents many points of interest. Five species not hitherto known to extend south of the British Isles were found by the Huazley, and in several cases important additions have been made to our knowledge of the bathymetric range. A specimen which has been tentatively referred to Periclimenes Korni (Lo Bianco) is of the greatest possible interest, for no deep- water representative of the family Palemonide was hitherto known from the N.E. Atlantic. Unfortunately, the species is represented only by a fragment of a single individual; this is particularly irritating, for the collection, as a whole, is ina remarkably good state of pre- servation. No close comparison can be made between the species in the present collection and those found by the Caudan in 1895, for the latter expedition worked considerably to the south of the area investi- gated by the Hualey ; nevertheless, two species, Spongicola Koehleri and Uroptychus Bouwviert, which were first described from material obtained by the Caudan, have again been found. Until now, both these forms were known only from the type specimens. My thanks are due to Dr. E. J. Allen for the opportunity of examining this interesting collection. NEW SERIES.—VOL. VIII. No. 5. Marcu, 1910. 2K 408 THE DECAPODA COLLECTED BY THE “HUXLEY” FROM THE DECAPODA NATANTIA. PEN AIDEA. SERGESTID &. Sergestes arcticus, Kroyer. Station VIII. Surface. Many, 9-22 mm.* - X. Surface. One, very small. a XII. 246 fathoms. Five, 29-35 mm. The majority of the specimens only measure from 9 to 15 mm. in length, and the largest (35 mm.) is not half grown. The examples from St. XII were probably caught in midwater during the ascent of the net. STENOPIDEA. STENOPIDZ. Spongicola+ Koehleri, Caullery. Station XIIT. 412 fathoms. Twenty-three, 25-46 mm., and several very young, about 8 mm. Prior to the date of the Huz#ley’s cruise, this interesting species was known only from five specimens dredged in the Bay of Biscay in 770 fathoms by the Caudan expedition. The additional examples, while in the main confirming the accuracy of Caullery’s{ description, show a very considerable amount of variation in the spinulation of the carapace and certain appendages. This variation is indeed so great that no specimen in the collection exhibits precisely the same armature on both sides of its body. The following notes indicate the numbers of spines and spinules observed in some of the more important positions. : The rostrum bears from 6 to 9 teeth on its dorsal aspect. Ventrally there are two ridges (for the rostrum is triangular in section), each of which is furnished with from 0 to 4 spinules. Occasionally the fore- most spinule is median in position owing to the confluence of the two ridges near the apex. The rounded antero-inferior angle of the carapace bears from 1 to 4 short spines, and from 1 to 4 are situated on the lateral face of the carapace a little behind the margin. At the * The measurements of all the Natantia mentioned in this paper were taken from the tip of the rostrum to the apex of the telson. + Bouvier (Mem. Mus. Comp. Zool., Harvard, XXVII, 3, 1909, p. 264) gives a useful table for the discrimination of the five species comprised in this genus. t ‘‘Schizopodes et Décapodes dela Campagne du Caudan.” Ann. Univ. Lyon, XXVI,, 1895, p. 382. NORTH SIDE OF THE BAY OF BISCAY IN AUGUST, 1906. 409 base of the rostrum on either side there are from 0 to 3 spines, while the posterior margin of the gastric groove may be wholly unarmed or may be provided with as many as twelve spinules. There are from 2 to 5 spinules, often blunt and inconspicuous, on the outer margin of the antennal scale, and from 4 to 14 on either side of the telson. There may also be one or two stout spines on the internal margin of the merus of third pereiopod. The eyes, as Caullery has observed, are devoid of black pigment, except for an annular band at the proximal edge of the cornea. The small and rudimentary exopod which Spence Bate has figured * at the base of the third maxillipede of Spongicola venusta is not found in S. Koehleri. The Hualey, like the Caudan, obtained several very young specimens of this species. Those in the present collection measure about 8 mm. in length and evidently represent the earliest free-living stage, for some remain curled up as though still within the eggshell. The rostrum and all the appendages of the cephalothorax are well developed in these specimens, while the eyes are just as deficient in pigmentation as they are in the adult. The pereiopods are fully segmented, and chele are present on the first three pairs, those of the third pair being very noticeable owing to their large size. Conspicuous exopods are retained on the first three pairs. The pleopods are well formed, but the. uropods are not yet free and the telson is shghtly emarginate distally. An ovigerous female was found to be carrying sixty-two eggs. As in the case of the type specimens, the examples of S. Koehleri collected by the Hus«ley were living in the sponge Regadrella pheniz ; as a rule a single individual was found inside each sponge. CARIDEA. PASIPH AID &. Pasiphaé sivado (Risso). Station VIII. Surface. Many, 35-55 mm. IX. 240 fathoms. Eight, 59-69 mm. X. Surface. Many, 8-26 mm. XII. 246 fathoms. Twenty-nine, 21-40 mm. XIII. 412 fathoms. Two, 40 and 58 mm. Only once previously has this species been recorded from depths exceeding 400 fathoms: by Adensamer, from 543 fathoms in the Mediterranean. * Challenger Report, 1888, Pl], XXIX, Fig. i”. 410 THE DECAPODA COLLECTED BY THE “HUXLEY” FROM THE Pasiphaé -princeps, Smith. Station XII. 246 fathoms. One, 69 mm. This solitary individual is specifically identical with a number of specimens found off the west coast of Ireland. These, although differing in certain features from the original description, have been determined as P. princeps, Smith, a species closely allied to P. tarda, Kroyer, but extending much further south. P. princeps had not hitherto been found in as little as 246 fathoms. PANDALID. Pandalus leptocerus, Smith, var. Bonnieri, Caullery. Station IX. 240 fathoms. Twenty-six, 35-ca.110 mm. XII. 246 fathoms. Thirty-three, 25-98 mm. Pandalus propinquus, G. O. Sars. Station VII. 444 fathoms. Nineteen, 27-70 mm. IX. 240 fathoms. Eight, 27-34 mm. XII. 246 fathoms. Fifteen, 18-35 mm. » XIII. 412 fathoms. Thirteen, 3l—ca.75 mm. P. propinquus had not previously been recorded as far south as the Bay of Biscay. Plesionika martia (A. Milne-Edwards). Station XII. 246 fathoms. Five; one perfect, 90 mm. (1) ,, XIII. 412 fathoms. One, large, in very bad condition. The large individual from Station XIII cannot be satisfactorily determined. It appears to have been swallowed by a fish and partially digested. 9 ”? Pandalina brevirostris (Rathke). Station IX. 240 fathoms. Three, 21-25 mm. » XII. 246 fathoms. Thirty, 12-25 mm. Several of the female specimens are ovigerous. HIPPOLYTID. Hippolyte varians, Leach. Station II. 75 fathoms. One, 17 mm.; an ovigerous female. Caridion Gordoni (Spence Bate). Station IX. 240 fathoms. Four, 16-21 mm. » XII. 246 fathoms. Eight, 14-185 mm. The rostra of these specimens bear from six to nine teeth above and from one to three below. : NORTH SIDE OF THE BAY OF BISCAY IN AUGUST, 1906. 411 C. Gordoni was not previously known to the south of the British Isles, and hitherto had not been trawled in depths exceeding 200 fathoms. PROCESSID A. Processa canaliculata, Leach. Station II. 75 fathoms. Two, 26 and 30 mm. 5 V. 109 fathoms. Seventy-six, 21-50 mm. Two of the specimens have abnormal eyes. The cornea on one side is well developed and of the usual size, whereas that on the other side is much smaller with, in one case, a curious swelling on the inner face of the stalk. The rostrum of the latter specimen is also unusually short, and is not furnished with its full complement of sete. PALAMONID&. Periclimenes Korni? Lo Bianco. Station XIII. 412 fathoms. Fragment. The rostrum of this specimen is broken off at the base, and the whole of the abdomen is missing. This is particularly unfortunate, for the specimen is, as far as I am aware, the only deep-water Paleemonid which has been found in the North-East Atlantic. It appears to be most closely allied to the imperfectly described Periclimenes (Anchistia) Korni (Lo Bianco),* found near Capri in about 600 fathoms, but is considerably larger and differs from the Italian author's figure in the lengths of various segments of the pereiopods. The carapace measures 7 mm. from the back of the orbit to the hinder margin of the carapace; it is therefore probable that the specimen was originally more than twice as long as the types of P. Korni, which were only 13-15 mm. in total length. The rostrum is broken, but four dorsal teeth are present on the anterior third of the carapace behind the orbital notch. The dorsal carina is clear and distinct for three-quarters the length of the cara- pace, fading away further back. Both hepatic and antennal spines are present. The eyes are deeply pigmented and the cornea is wider than the stalk. The outer antennular flagellum is split into two rami, the inner one (which is also the thicker) being slightly longer than the fused basal part. The lamellar portion of the antennal scale is produced acutely at its inner distal angle, and reaches considerably beyond the stout spine which terminates the straight outer margin. The first pair of pereiopods reaches beyond the apex of the antennal scale by the whole length of the propodus; the merus and * Lo Bianco, Mitt. Zoo. Stat. Neape/, 1903, p. 250, tav. 7, fig. 13. 412 THE DECAPODA COLLECTED BY THE “HUXLEY” FROM THE carpus are nearly equal in length, each being about one and a half imes as long as the chela. The second pair is characterised by the very long but comparatively slender chela, which is twice the length of the merus. The carpus is very short, about one-third the length of the merus, and the dactylus is half the length of the palm. The dactylus is strongly curved and sharply pointed apically; it bears a prominent longitudinal carina on either side and a sharp tooth in- ternally in the middle of its basal third. The fixed finger is carinate along its internal aspect only, and bears, in its basal third, two teeth, between which the dactylar tooth fits when the claw is closed. In the last three pairs of pereiopods the propodus is slightly longer than the merus, the carpus is three-fifths the length of the propodus, and the dactylus is very short, simple, curved, and claw-like. CRANGONID. Crangon Allmanni, Kinahan. Station II. 75 fathoms. Nine, 18-26 mm. V. 109 fathoms. Many, 14-25 mm. » XL 146 fathoms. Many, 12-27 mm. The capture of this species on the north side of the Bay of Biscay in 146 fathoms establishes new records both for its horizontal and bathymetric distribution. C. Al/manni had not hitherto been found south of the British Isles, and was not previously known from depths exceeding 100 fathoms. The small size of the specimens seems to indicate that the species is unable to attain its maximum development in deep water. 39 Philocheras* echinulatus, M. Sars. Station IX. 240 fathoms. Forty-eight, 14-34 mm. XII. 246 fathoms. Many, 14-35 mm. ? This species was not previously known as far south as the Bay of Biscay. Philocheras bispinosus, Hailstone, var. neglectus, G. O. Sars. Station II. 75 fathoms. Two, 11°5 mm, These two specimens show no trace of the brown pigment which is sometimes such a prominent feature of the var. neglectus when living. The surface of the carapace and abdomen is, however, without trace of tubercles, and is pitted with microscopic punctuations exactly as in the forms with transverse brown bands. * Philocheras, Stebbing, nom. nov. vice Cheraphilus. NORTH SIDE OF THE BAY OF BISCAY IN AUGUST, 1906. 413 P. bispinosus var. neglectus had not hitherto been recorded from as far south as the Bay of Biscay nor from as much as 75 fathoms. The typical form is, however, known to extend to the Azores and has been found off the west coast of Ireland in as much as 200 fathoms. Asgeon Lacazei (Gourret). Station IX. 240 fathoms. Fourteen, 19°5-28 mm. » II. 246 fathoms. Eight, 20-25 mm. This scarce species is closely allied to the common Mediterranean form A. cataphractus. It was originally described by Gourret from specimens found in the vicinity of Marseilles, and since then twelve examples have been trawled off the west coast of Ireland between 160 and 374 fathoms. Pontophilus spinosus (Leach). Station IX. 240 fathoms. Seven, 28-38 mm. » XII. 246 fathoms. Three, 9-12 mm. Pontophiius norvegicus, M. Sars. Station XII. 246 fathoms. Three, 13-17 mm. DECARODA REPTANTEA ERYONIDEA. ERYONID. Polycheles typhlops, Heller. Station XII. 246 fathoms. Two, 29 mm. SCYLLARIDEA. PALINURID. “ Phyllosoma” (larva). Station VIII. Surface. Two. GALATHEIDEA. UROPTYCHID2. Uroptychus rubrovittatus (A. Milne-Edwards). Station VII. 444 fathoms. Four, 15-30 mm.* » XII, 412 fathoms. One, 19mm. * The measurements of all the Galatheidea mentioned in this paper were taken from the apex of the rostrum to the extremity of the telson, with the abdomen stretched out in macrurous fashion. 414 ‘THE DECAPODA COLLECTED BY THE “‘HUXLEY” FROM THE Uroptychus nitidus var. concolor (A. Milne-Edwards). Station XIII. 412 fathoms. One, 30 mm. Uroptychus Bouvieri, Caullery. Station XIII. 412 fathoms. Three, 14°5-22 mm. This is the first time this species has been recorded since it was. described by Caullery.* The type specimens, two males, were found by the Caudan expedition between 218 and 275 fathoms. Two of the examples collected by the Huxley are ovigerous females, and measure 22 and 20°5 mm. from the tip of the rostrum to the apex of the telson; the third is a male, 145mm. in length. The first perelopods measure 26, 24, and 23°5 mm. respectively, thus showing that this limb is much more strongly developed in the male than in the female. Little can be added to Caullery’s careful description. The small median denticle behind the base of the rostrum is absent in all the specimens, the lateral spines on the carapace vary in number from five to six, and the antennal scale reaches to two-thirds the length of the rostrum, and is narrower at its base than in the figure of the type. The notch in the sternal plaston is, in the female, rectangular in shape, and considerably deeper than in the male. Only four longitudinal rows of spines can be found on the merus and carpus of the first pereiopod, and the internal edge of the propodus of the same limb is upturned and denticulate proximally and is separated from the smooth dorsal surface by a well-defined groove. The eggs, which appear to be on the point of hatching, measure about 1°5 mm in length. Gastroptychus formosus (A. M.-Edw. and Bouvier). Station VII. 444 fathoms. One, 18 mm. » IIT. 412 fathoms, Two, 21 and 38 mm. One of the specimens from Station XIII is an ovigerous female. GALATHEID&. Galathodes tridentatus (Esmark). Station VII. 444 fathoms. Twenty-four, 6°5-28 mm. » AIIT. 412 fathoms. Four, 18-20 mm. Nine females are ovigerous. we 66 Schizopodes et Décapodes de la Campagne du Caudan,” Ann. Univ. Lyon, XXVI, 1895, p. 394. NORTH SIDE OF THE BAY OF BISCAY IN AUGUST, 1906. 415 Galathea nexa, Embleton. Station II. 75 fathoms. Two, 16 and 23 mm. ns V. 109 fathoms. One small; broken. 5 Xe 846 fathoms: Six, 10-21 mm. » XII. 246 fathoms. Two, 15 and 18 mm. Compared with Bonnier’s figures the third maxillipede in these specimens bears a closer resemblance to G. dispersa than to G. neva. recent authors are, however, agreed that these two forms are merely variations of a single species, and although the form known as dispersa is far the commoner, yet this name must lapse in favour of nea, which has priority.* Munida bamffica (Pennant). Station IX. 240 fathoms. ‘Two, 24 and 33 mm. » II. 246 fathoms. Four, 25-33 mm. » XIII. 412 fathoms. One, 23 mm. Although the specimens are small, they all present the scaly appearance on the thoracic sternum which so readily separates this species from its close ally AZunida tenuimana.* PAGURIDEA. PAGURIDA. Eupagurus bernhardus (Linn.). Station II. 75 fathoms. One, very small. Eupagurus Prideauxi (Leach). Station IT. 75 fathoms. Five. -e V. 4109 fathoms. Four. jee Ve 2 8? fathoms, One. In the largest specimen, which is an ovigerous female from Station VI, the carapace measures 15 mm. in length. Eupagurus variabilis, A. M.-Edw. and Bouvier. Station IX. 240 fathoms. Twenty-six. a XI. 146 fathoms. Sixteen. » XII. 246 fathoms. Twelve. » XLII. 412 fathoms. -One. The largest example, taken at Station IX, measures 62 mm. from the hinder margin of the cephalothorax to the distal extremity of the large chela. All the specimens are typical in form with the exception of two, in which the propodus of the right chela is slightly excavate. * y, Hansen, Danish Ingolf Malacostraca, 1908, pp. 31 and 32. 416 THE DECAPODA COLLECTED BY THE “HUXLEY” FROM THE Eupagurus carneus, Pocock. Station VII. 444 fathoms. One. » XIII. 412 fathoms. Two. The largest specimen measures only 28 mm. from the hinder margin of the cephalothorax to the distal extremity of the large chela. Anapagurus levis (W. Thompson). Station IT. 75 fathoms. Seven. is V. 109 fathoms. Twenty-two. >, ' EX. 240 fathoms, ~-Two. 5 owl 146 fathoms: 2 Six: Xi 246 fathoms:. Hour: OXYSTOMATA. DORiPPID. Cymonomus granulatus (Norman). Station XII. 246 fathoms. One, 4 mm.* LEUCOSIID. Ebalia tuberosa (Pennant). Station V. 109 fathoms. This species does not seem to have been recorded hitherto from as much as 109 fathoms. One, 12°5 mm. Ebalia tumefacta (Montagu). 75 fathoms. 109 fathoms. Station IT. bP] AF; One, 7 mm. Two, 8 and 8-5 mm. Ebalia nux, Norman. Station V. 109 fathoms, One, 7-5 mm. » IX. 240 fathoms. Eight, 6-5-8-5 mm. » X&. 146 fathoms. Three, 7-7-5 mm. » XII. 412 fathoms. 7-8 mm. Several of the specimens are ovigerous females. BRACHYGNATHA. PORTUNID&. Portunus holsatus, Fabricius. Eighteen, 10-5-18 mm. Three, 6-5-8-5 mm. 75 fathoms. 109 fathoms. Station IT. + Wh * Length of carapace. NORTH SIDE OF THE BAY OF BISCAY IN AUGUST, 1906. 417 The specimens are all very young, but in my opinion they can be referred with safety to this species. Hitherto P. holsatus has not been recorded from depths exceeding 70 fathoms. Portunus pusillus, Leach. Station V. 109 fathoms. Eighteen, 5-9 mm. s It is with some doubt that these small specimens are referred to P. pusillus. The median frontal tooth is, in several instances, not more advanced than the lateral, but it is probable that with growth this feature would become more apparent. Portunus tuberculatus, Roux. Station III. 75 fathoms. Two, 27 and 29 mm. re V. 109 fathoms. Three, 17-21 mm. VI. 87 fathoms. Three, 21-22 mm. Polybius Henslowi, Leach. Station II. 75 fathoms. One, 36 mm. Bathynectes superba (Costa). Station VII. 444 fathoms. Two; one 11 mm., one broken, y IX. 240 fathoms, Seven, about 5-5 mm. 5 XII. 246 fathoms. Fifty-three; one large and very macerated, the rest 5—6 mm. » XAID. 412 fathoms: Four. In the small specimens the form of the carapace resembles Bouvier’s figure * of an individual 4°5 mm. in length; the frontal margin is four- lobed, the second and fourth antero-lateral spines are extremely short, while the fifth is not specially longer than the third. In the two large specimens from Station XIII the hindmost spines of the antero- lateral series are very long; they measure 50 and 46 mm. in breadth without these spines, while, including them, they measure 84 and 80 mm. Geryon sp. ? Station XII. 246 fathoms. One, broken, 5 mm. ATELECYCLID#. Atelecyclus septemdentatus (Montagu). Station II. 75 fathoms. Two, 15 and 17 mm, * Bouvier, Rés. Camp. Sci. Monaco, XIII, 1899, Pl. II, fig. 1. 418 THE DECAPODA COLLECTED BY THE “HUXLEY” FROM THE MAIID&. Inachus dorsettensis (Pennant). Station V. 109 fathoms. Four, 13-18 mm. » Vi. 87 fathoms. Two, 19 and 20 mm. Inachus leptochirus, Leach. Station IT. 75 fathoms. Sixteen, 12-22 mm. » VI. 87 fathoms. Five, 18-22 mm. » XI. 146 fathoms. Two, 9 and 12°5 mm. Stenorhynchus longirostris (Fabricius). Station II. 75 fathoms. Twelve, 10-20 mm. A V. 109 fathoms. Two, 9°5 and 17°5 mm. » LX. 240 fathoms. One, 22 mm. Lispognathus Thomsoni (Norman). Station VIL. 444 fathoms. One, 7 mm. » XIII. 412 fathoms. Four, 4-7 mm. Ergasticus Clouei, A. Milne-Edwards. Station V. 109 fathoms. One, 8 mm. 3 IX. 240 fathoms. One, 11 mm. 5 XII. 246 fathoms. Four, 9-18 mm. Hyas coarctatus, Leach. Station VI. 87 fathoms. 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TUURU]]y Wosued—D j IIOY, SouOUITpOTIeg BYR[NOT]VULd VSS9D01J 1WOp1o+) UOTPIIRD sures oyAjoddrpy SLISOITAGIG VUTTRpuRT BIJIVUL VYIMOTSOT J * snnburdoad snyepurg letuuog *A sniao0qday snyepueg sdaound seydiseg * opeats avydiseg Lolye0y epooisuodg SNOTJOIR SoqysaD.1og “BIJUeBN Gh &E 09 FG SP ad ~ SB 9 XZ SP * smoyqea "M ‘apnqisuo0'T *N ‘opngygeT ‘Gadd NOOO AWA HOTHM LY SNOILVLS ‘ON NOLLVIS INV ‘SHIOWdS HO LSIT THE DECAPODA COLLECTED BY THE “ HUXLEY.” 420 | it wae | oe 7 see | iE re wee see I | eee . a see | . | * . if | oe i} ii balk x & al . oh i soe ee 55s is aT ; a z 5 ee iF 1 Fs “ an sae lety | I g Be plats ag SL | eee eee RN ee SI i Zz | wee iL | ae is iL wee | . . . wae . aoe | wee oe netted wel Oe aamal em z Late, lee ZG ‘yf L I CL | 9L eee 9% on | ere oe eee | | I p eS g | | I , 4 iF Z P rot sks . cs a ee = ae Z a a = Clr 9FG 9FL *VOBJANG OG “VOVJANS Aa? > | 48 601 GL GL SI 8 LT 8 UL 8 ST 8 S&T oS 18 ob TE o4 s61 od 19F ob, SE 0 SG oD 14 BP 14 8F OL .8P 4 8F 4 SP 08 oLF 98 oLP i9P oLP iS¥ oLP iG SP PG SP 2 eae 1008 Gaw-e IX x xI IIIA | IIA IA A III II . . ° . . . * snqejorr0o seATT Teno[D snoysesiq 1UOSOT,T, snyyeusodsry SLIJSOMSUOT SnyoUAYIOUDIG , ¢ : : p * — snatyooqday snyoeuy SISUa}jasIop SNYOBUT : : : ; * suyvjueputeydes snjofoe]0} 3 . . : : : ° - ds uokiay eqiadns saqooudyyeg IMo[suapy sutqdAjog snyeNo1aqny suunq.og snqpisnd snunqi0g snyes[oy snunztog ; ; ; ; ; : : * xnU eBIEqhA * BpORJOUINY VILE : : : : : : * Bsoleqny BIpeqiy snqepnueis suutouoWAd : : : : : : SIAar, suansedeuy sneuied sninsedug ST[IqvlIvaA sninoedngy * Ixnvaplig snainsedny supieyureq snansed ng * RolyUreq BplUny D : : : ; : ‘ - Bxol BAT] RTVYD SNyejUapll} Sapoyyey[ey . . . . . . . . . . . . hase : + suoyy Rey “+ *M fepngtsuory SB 8 Sie HAVANT we OL CON eNOnn yn ‘penjvoo— T4WaaNO0O AUHL HOIHM LV SNOLLVLIS HHL AGNV ‘SHIOHdS AO LSIT pat | On the Artificial Culture of Marine Plankton Organisms. By E. J. Allen, D.Sc, Director of Laboratories and Secretary to the Council of the Marine Biological Association, and E. W. Nelson, Assistant Naturalist. fe Wr PAGE Introduction . : : : é Bigs te 7) I. Culture of Pieniean Bitons : 3 : ; 5 423 A. Practical Culture Methods ; ; : 3 » e423 J. Miquel’s Method . é : : ; . 423 2, Houghton Gill’s Method ; : Z : ~ 2426 3. (a) Modification of Miquel’s Method. ‘* Miquel Sea-water” sm 42H (6) English Channel Water . : : 5 he a2 (c) Tank-Water . ; ; : ; a 430 (7) Animal-Charcoal Water . : : é e743 (e) Peroxide of Hydrogen Water : ‘ : . 434 (7) Cultures in these Media . 435. b. Experiments with a view to Determining the Comins ase mils the successful Culture of Diatoms . ; é . 436 Methods F : ; s : f ES The Sea-water poled : : : _ 407 The Constituents of Miquel’s Solna : : : . 488 Animal Charcoal and Peroxide of Hydrogen : : cae Reviving Exhausted Cultures. : : ; - 443 Silica 5 ‘ . ; : : . 444 Organic Infusions : 3 : ; , ee 23) Artificial Sea-water . : : : ‘ . 446 Alkalinity . 3 3 : é L oo cal Salinity : : : : ae don Light : : : : : : . 463 Temperature . ‘ 5 ; 3 2 Ab General Conclusions. ; : : 4 - 455 II. Mixed Cultures. 457 Ill. Notes on particular species so Datars on their methods of Benradie tion, aad on other Alge occurring in Cultures : A : aero) IV. Rearing of Marine Larve . : ; : ; . 464 Methods : : ‘ ‘ . ; . 464 Echinus acutus . 5 - : : : . 466 E. esculentus . . : : é * oo Slates EB. miliaris : : ; 5 5 : Sry Cucumaria saxicola : : , : : on Pomatoceros triqueter : : ; : : . 468 Chaetopterus variopedatus . 3 : é ; ToS Sabellaria alveolata : 5 : : : a Archidoris tuberculata 2 , ; j : 5 469 422 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. PAGE Calanus finmarchicus ; : : : : eee (O) Echinus hybrid . : 5 ‘ : : pee el) Saceulina carcini . : 5 “ : . 470 Summary of Method for Rearing Larve : : : on ety Bibliography . : é bs . ; : a = Introduction. The observations to be recorded in this Paper were commenced in March, 1905. They originated in an attempt to find a general method for rearing marine larval forms. Several investigators had previously succeeded in rearing Echinoderms, Molluscs, and Poly- chetes from artificially fertilized eggs under laboratory conditions, but the process was generally difficult and the results more or less uncertain. ‘The most promising method seemed to be that adopted by Caswell Grave (26), who was able to rear his larve by feeding them on diatoms. Grave obtained his diatoms by placing sand, collected from the sea bottom, in aquaria and using such diatoms as developed from this material. All the methods, however, suffered from the uncertainty of not knowing what organisms were introduced into the aquaria in which the larvee were to be reared, either in the original sea-water or along with the food-supply. It appeared, therefore, at an early stage of the work, worth while to make an attempt to carry out rearing experiments on a more definite and precise plan, to endeavour, in fact, to introduce the larve to be reared into sterile sea-water, and to feed them with pure cultures of a suitable food. This was the ideal to be aimed at. As a matter of fact, it has seldom, if ever, been attained in practice; nevertheless a considerable measure of success has been achieved by working upon these lines, and during the course of the work innumerable problems relating to the physical conditions under which plankton organisms can best flourish have presented themselves. Some account of the experi- ments made may be of interest to other workers, although many of the problems raised are not yet solved, notwithstanding the fact that some 1500 cultural experiments have been under observation. It is rather with a view of stimulating other work upon similar lines, than of bringing forward conclusive results, that this paper is being published. In the summer of 1907, Mr. E. W. Nelson became associated with the investigation, and since that date the experimental work has been carried out by him. The discussions in this paper of a more chemical character, particularly the section on alkalinity, are almost entirely the work of Mr. Nelson, and we have both had throughout the advantage of the constant advice and help of Mr. D. J. Matthews on all such matters. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 423 L CULTURE OF PLANKTON DIATOMS. A. PRACTICAL CULTURE METHODS. 1. Miquel’s Method. Attention was first directed to the culture of Plankton diatoms; and the methods, which had been elaborated by Miquel (11) for fresh-water diatoms and had been found by him to succeed with marine-bottom diatoms, were tried. The essential features of Miquel’s method, as applied to marine diatoms, are as follows :— Two solutions are prepared :— Sonution A. Magnesium sulphate. : ; ; 10 grm. Sodium chloride . 2 2 : P . ‘ TOR. Sodium sulphate . A f : j ; Dies: Ammonium nitrate : ; : : b haere Potassium nitrate ; ; : 3 ; : Die a Sodium nitrate : ; De 3 Potassium bromide 4 : : : ; td OF 2 Potassium iodide . : : ‘ ; Suh Oct Water ' : 4 ; : ; By OO s. Sotution B.* Sodium phosphate : ‘ ; : 4 orm. Calcium chloride (dry) 2 : 4 pee Hydrochloric acid . ‘ 5 7 2 ce. Ferric chloride. 3 . ; ; : *SHOOM Ss SoLurTion 2. Crystallized magnesium sulphate Bes Rs sodium sulphate are ; potassium nitrate Ts Common salt (sodium chloride) Sins Potassium bromide Potassium iodide . ooo bo bo Water 0, SoLuTion 3. Crystallized sodium carbonate : ; ‘ : AVS Water : : : : : : : at HOO 3 Souurion 4. Well-washed, precipitated calcium silicate. : ZOU y3 Water , ; : : : : 4 3 (45) as All the salts employed must be chemically pure. Three cc. of each of these liquids are added to 1000 cc. of fresh water or sea-water (according to circumstances), and the whole sterilized. In his earlier work Houghton Gill added a sterilized infusion of grass or of diatoms, but it is not clear from the accounts whether this was still employed with the above solutions. We have obtained very good cultures with the above solutions, to which we did not add any organic infusion. 3 (a). Modification of Miquel’s method. “ Miquel Sea-water.” Since several of the components in Miquel’s formula for solution A (p. 423) are obviously unnecessary, when sea-water is being used as the basis of the culture-medium, we adopted for our own work the following modifications :—After some preliminary experiments it was found, as would be expected from the composition of sea-water, that the only salts of value to the medium are the three nitrates, KNO,, NaNO., NH,NO,, and possibly KBr and KI. The omission of the two latter was soon found to make no difference. Experiments also showed that the formula for solution A could, without any appreciable detriment to results, be further simplified to the one salt, KNO,, or NaNO,, but not NH,NO,. At first the amount of KNO,, dissolved in 100 ce. distilled water, used to make the modified solution A, was the same as the sum of the weights of the nitrates in 428 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. Miquel’s own formula, viz. 5 grm. But later experiments showed that a considerably greater concentration of KNO, than this gave more lasting cultures; the strength of solution, and amount to be added to a litre of sea-water, in order to obtain the best results, being 2 cc., 2M, KNO,. In the case of solution B no modification has been adopted, but it has been found that small variations in the amounts of the ingredients used do not affect the results. A convenient method for measuring the right amount of FeCl, is to warm the salt until it just melts in its own water of crystallization, and to pipette out 2 cc. with a previously warmed pipette. No temperature corrections need be con- sidered. Also 2 cc. of the ordinary pure concentrated hydrochloric acid at room temperature will suffice. Our own formula for preparing Miquel sea-water is now :— SouuTion A.* Delonas en 90-9 op iE PSone nitrate . : : . 2072 grm: ) 2M KNO, Distilled water : ; ‘ SLOOS os eta Sotution B.7 Sodium phosphate (Na,HPO,12H,O) 4 Calcium chloride (CaCl,6H,O) . 4 Ferric chloride (melted) 2 Hydrochloric acid (pure, concentrated) 2 ¢ Distilled water 80 ” ” cc, cc. To each 1000 cc. of sea-watert add 2 ce. solution A and 1 ce. solution B, and sterilize by heating to 70° C. When cool, decant off the clear liquids from the precipitate, which will have formed when solution B is added to the sea-water. As a rule our cultures were made in 60 ce. ier this medium, con- tained in short-necked, wide-mouthed flasks of 125 cc. capacity, sa that the proportion of air-surface to volume of liquid was large. The medium was found to give constantly satisfactory results. On inoculation from a persistent culture of such diatoms as Zhalassvosira, Skeletonema, Chaetoceras, etc., a growth visible to the eye is obtained in about ten days, and then multiplication takes place very rapidly. In from three weeks to a month’s time a very considerable growth will be seen making a brown, flocculent mass at the bottom and back of the vessel containing the culture. * This strength has only been used in the most recent experiments ; and solution A in this paper, unless otherwise stated, means the five per cent solution of KNO,. + For preparing this solution see p. 423. + ‘* Miquel water” seems to succeed equally well, whether it is made by adding Miquel’s solutions to ‘* outside water”? or to ‘‘ tank water” (cf. p. 437). ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 429 In from three to four months the culture begins to show signs of exhaustion and the frustules lose colour, but they do not, as in the case of sterilized outside and tank water, completely die off. A great number certainly do die, but some remain in a resting condition, and often, after a period of six months or so, these begin to multiply again and the culture regains its former vigour. This is probably due to the food-stuffs contained in the dead frustules going into solution again, possibly by means of bacterial action. This periodicity in cultures is interesting in that it resembles what takes place in the ocean. Cultures in this medium will persist indefinitely, so far as our experience goes. The oldest culture in our possession is one of Skeletonema costatum, made at the very commencement of this work, dated April, 1905. Although the frustules in this culture are quite unrecognizable as any diatom now, on making a subculture in fresh Miquel a normal and healthy growth can always be obtained. In old cultures the diatoms are nearly always found to be very much deformed, and often appear to be only a mass of broken-down chromatophores. Whether regeneration can be successfully obtained from a single chromatophore, which must presumably be contained within a cell-wall of some kind, has not been definitely decided, but results seem to point in this direction. At the start of a culture a tendency to teratological forms is often exhibited, but when the growth is well advanced, the shape of the frustules is usually quite normal. (>) English Channel Water (“Outside Water”)—In a large number of our experiments sea-water brought in from outside the Plymouth breakwater, and therefore taken at some distance from the shore, has been used. This is referred to as “outside water.” It has an average salinity of about 35:0 °/,., and the temperature range for the year is from 8° C. to 16° C. If a sample of “outside water” is. inoculated from a persistent culture of a plankton diatom, a small growth is obtained in from five to fifteen days. But soon minute bottom forms of diatoms, other alge, flagellates, infusoria, etc., appear, and the inoculated species is lost. The total growth of any form is never large. If the growth of these foreign forms is prevented by sterilizing the water before inoculation, a considerably better growth of the plankton form is obtained. The water was, as a rule, sterilized by simply heating to 70° C., which temperature was found to be quite adequate. Boiling gave equally good results, but the former was preferred, as less con- centration due to evaporation took place. Even under these conditions 00) 430 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. no permanent culture can be obtained, the diatoms soon beginning to lose colour and getting into an exhausted condition. Death takes place in from two to three months after the culture has been started, and in many cases considerably sooner. Long before inability to start new cultures, the test of death, has been established, the valves appear on examination quite colourless and practically empty. Samples of outside water, taken at times when the quantity of plankton was widely different, gave no appreciable variation in the results obtained by culture methods. It is, however, doubtful whether differences in the amounts of growth in cultures, proportional to the seasonal variation in the quantity of phytoplankton, would be suffi- ciently marked to be appreciable. The total growth under cultural conditions, although small for a culture, is very much greater than any natural plankton that has come within our experience. (c) LTank-water.—* Tank-water” or water taken from the supply of sea-water circulating through the tanks of the Aquarium at Plymouth, shows some striking and interesting differences from “outside water.” This water is pumped up from the sea, just below the Laboratory, into two large, covered-in, settling reservoirs, with a capacity of 50,000 gallons each. Pumping is only done at high water, spring tides, so as to get the least contaminated water, and no water is pumped that does not show a specific gravity, measured with a hydrometer, of p= 26:00 (S = 34:00) orover. The water is allowed to settle for about a fortnight before being used for the general circulation. The tanks themselves are made of slate and glass, and the pipes which convey the sea-water to them are of vulcanite, so that the water does not come in contact with metal, excepting in the pumps, which are of cast-iron, The two settling reservoirs are used alternately, for about a week each. From time to time, tide and water allowing, waste is replenished, and about twice a year each reservoir is emptied, cleaned out and refilled. The aquarium takes about 20,000 gallons, and this is in circulation with one of the two 50,000-gallon reservoirs. An estimate of the amount of life in the tanks of the aquarium must be exceedingly rough, but the intensity of the larger forms of life is far greater than anything met with in natural waters. About 500 fish and 2000 invertebrates, including all forms as large as an Actinia equina, might be somewhere near the mark. So it will be seen that the accumulation of excretory products must be a by no means negligible factor. The flora of the tanks is very restricted, and is chiefly composed of minute forms of alge. Minute naviculoid diatoms, ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 431 fetocarpus, Cladophora, Enteromorpha, Vaucheria, and unicellular algze are the commonest forms. The large seaweeds, such as Mucus and Laminaria, do not live long if introduced. Plankton diatoms, although a great number must: be pumped up when the reservoirs are being filled, are not represented. As in the case of outside water, a sample of “tank-water,” in- oculated from a persistent culture, will only give a very small growth, minute forms, etc., soon multiplying and choking out the plankton form. The ultimate growth of minute unicellular alge other than diatoms is often considerable, and many quite unknown and unidentified forms have been obtained. The total growth of vegetable forms is always found to be greater than in the case of outside water. In cultures of plankton diatoms made with sterilized tank water, a very great improvement on outside sterilized water was always noted. The culture of the diatom used to inoculate this medium persists for a considerable period, and the colour of the frustules remains normal for two to three months. (d) Animal-Charcoal Water.—The use of animal charcoal, as a means of purifying the water in small aquaria, has for a long time been known and practised by those who have kept such aquaria in inland places. At an early stage in our experiments, water from a tank, which was not in a satisfactory condition, was treated with some powdered animal charcoal and filtered. It was noticed that a good growth of diatoms took place in this water. Systematic experiments with the use of animal charcoal were then commenced, and these have resulted in a method of great value, both for the culture of diatoms and for the rearing of pelagic larve. Animal charcoal is made by the carbonization of bones,* and is sold in two grades known as “pure” and “commercial.” Our earlier experiments were all made with “pure” animal charcoal, but subsequently the “commercial” animal charcoal was largely used and appears to give equally good, if not better resuits. In both cases the animal charcoal is used in the powdered form. Animal-charcoal water is prepared as follows :— 1. A quantity of sea-water is sterilized by heating it in a flask to * Analysis of Animal Charcoal, from Thorpe’s Dictionary of Applied Chemistry :— Carbon . § 5 : : . Odi Ca., Mg. phosphates, Ca. fluoride, ete. . 80°21 Calcium carbonate . : ‘ A F 8°30 Other mineral matter : : : _ | Ors! 100°00 432 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 70° C., at which temperature it should be kept for about twenty minutes. At the same time some animal charcoal is heated sufficiently to sterilize but not to burn it, covered over and allowed to cool. When both are quite cold, the charcoal is added to the water (ca. 15 grm. to. 1000 cc.) and well shaken up in it several times, After an interval of half an hour or more the water is filtered through fine filter cloth,* the whole filter having been first sterilized with boiling sea-water, and is received in a sterile flask. It is then ready for use. 2. For many experiments, where larger quantities of water were required, the sea-water was not sterilized before being treated with animal charcoal. In this case, if the first part of the filtrate be rejected, the subsequent water will generally be practically sterile, and few, if any, extraneous organisms will develop in it. oO 3. At a later date an automatic apparatus was set up in the Plymouth Laboratory, by which very considerable quantities of sea- water could be treated with animal charcoal, and subsequently filtered through a “Berkefeld” filter; water treated in this manner we call “Berkefeld water.” Tank-water was always used in this apparatus, and was mixed with animal charcoal,t in a clean sulphuric acid carboy, by blowing air through with a pair of bellows. The mixture was allowed to settle for at least twenty-four hours and then syphoned over into an inverted bell-jar, with a tubulure at the bottom, into which the Berkefeld candle was fitted. Filtration under these conditions was found to be rather slow; so, in order to increase its rate, an apparatus was devised by which the pressure on the filter was con- siderably augmented. This apparatus (see Fig. 1) consists of a glazed earthenware “tobacco jar” with two tubulures, one at the side, the other at the bottom, and a lid which can be screwed down tightly on to a rubber washer, by means of a triangular metal arrangement fitting into grooves above the lid{ The internal dimensions of our jars are 11x 6 inches, and the diameter of the opening at the top is 3} inches. The tubulures are coned, with the smaller diameter external, and make a good fit for a No. 8 rubber bung. When setting up this apparatus, a bung, through which a short glass tube bent at right angles is passed, is fitted into the * The filter cloth used for this purpose is the same as is made for use in filter presses, and is known as Extra-Super Swansdown. To prevent this becoming clogged another cloth, known as Hydraulic Twill, was, as a rule, used over it. + Ca. 300 grm. to 20 litres of water. t These jars were made, to our specification, by Messrs. Price, Powell, and Co., Bristol. The clamps usually supplied with such jars are not strong enough to obtain a tight joint, but these are easily replaced by stronger ones, ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 433 side tubulure. This tube is connected, by means of rubber pressure tubing, to another glass tube leading down from the bottom of a small inverted bell-jar, placed some height above (in our case 14 feet, which gives a pressure of ca. 6 lbs. to the square inch inside the jar). A screw pinch-cock on this connection serves as a tap. The carboy containing the treated water stands just above the bell-jar, and is fitted with a tightly fitting rubber bung, through which two tubes pass. One is an ordinary syphon, the other the only air inlet into the carboy. This latter automatically keeps the level of the water in the bell-jar Fic, 1.—Diagram of apparatus for preparing sterile sea-water by filtration, without contact with metal. constant, by closing the air-inlet as soon as the water covers the end of the tube. When filtering water, the modus operandi is as follows :— The carboy is filled with tank-water, treated, and allowed to settle as before. The Berkefeld candle,* bung, delivery tube, and connections (see Fig. 1) are sterilized by boiling for half an hour and fitted into place from within. (The delivery tube is shaped so that any drops of water, accidentally running down outside it, do not enter the vessel receiving the filtrate; and the jar should be large enough to allow the hand to fit the filter into place without much trouble.) The pinch-cock is closed and the syphon from the carboy started, which will automati- cally stop if the bung has been properly fitted. This should be watched to avoid accidents. The pinch-cock is then opened until the water rises in the jar well above the top of the candle, but still leaving some air space. The lid can now be fitted into place and screwed down. The tightness of this joint can be tested by pouring a little water into * No. 5. Porcelain-mount; length 8 ins., diameter 2 ins. 434 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. the crack round the lid, and observing if any bubbles are formed when the pinch-cock is opened. If all is right, no bubbles will be seen, and a good stream of water will flow out from the delivery tube. Our apparatus will filter about twenty litres an hour, and the filtrate is exceptionally bright and clear. The candle should be sterilized every three or four days that the apparatus is in use, to avoid indirect contamination by growths of organisms through the substance of the filter.* The water while passing through this apparatus only comes into contact with glass, earthenware, and rubber, the use of metal having been purposely avoided. (e) Peroxide of Hydrogen Water, As it seemed probable that the action of animal charcoal was due to contact oxidation with the oxygen occluded in the charcoal, experiments were made to determine whether a similar effect could be produced by the use of hydrogen peroxide (H,0,). This was used in two ways. In the first method a sufficient quantity of H,O, was added to the sea-water to ensure complete sterilization (1 ce. of H,O, of 20 vols. strength per 1000 ce. of tank- water was found to be satisfactory), and the excess of H,O, was decom- posed by adding manganese dioxide. The water was then filtered through filter cloth, and the filtrate appeared to remain quite sterile. Good cultures of Chaetoceras constrictum, Biddulphia mobiliensis, and Skeletonema costatum were made in this water, which seemed to be as good as water treated by the animal-charcoal method. The second way of using the peroxide of hydrogen was to start with water sterilized by heating to 70° C., and to add to this H,O,, in small quantities at a time, until its presence could just be detected on testing the sea-water with permanganate of potash. In these circumstances, the first amounts of H,O, are decomposed in the oxidation of organic substances in the water, and a very slight excess of H,O, persists. For tank-water 1 ec. of 1 vol. H,O, per 1000 ec. was found to give the best general effect. Cultures grown in water prepared in this way developed satisfactorily, being practically equal to those made in animal- charcoal water, but they became exhausted rather quickly. The treatment of aquarium water with ozone was also tried, as this seems to offer a possibility of treating large quantities of water,+ such as the whole bulk of water in an aquarium circulation, without very considerable expense. Experiments on a small scale, which we were able to make, unfortunately only with imperfect apparatus, showed * See Bulloch and Craw., Jour. of Hygiene, V1, No. 3 (1906) p. 409. + The use of ozonized air for the purification of fresh water for town-water supplies has ’ been adopted in some localities. See Bridge, J. H. Paper read before Franklin Institute, reprinted in English Mechanic (1907), pp. 369 and 392, ON THE ARTIFICIAL CULTURE. OF MARINE PLANKTON ORGANISMS. 435 that water treated with ozonized oxygen gave distinctly better cultures than untreated water. Although the sea-water was not absolutely sterilized by the treatment to which we actually subjected it, a sample of water which was visibly clouded with bacteria became quite clear and bright. (7) Cultures in these Media. In order to make clear the different results, which are obtained by using these different waters, we will describe the probable result which would be got from a series of flasks set up with the following media, and each inoculated with a persistent culture of a true plankton diatom, such as Zhalassiosira, Skeletonema, or Chaetoceras. A. “Outside water” untreated. Small growth in from five to fifteen days, almost immediately swamped by growths of foreign forms; the latter, however, will never be large. B. “Outside water” sterilized. Slightly larger growth, very soon becoming exhausted. C. “Tank-water” untreated. Same result as in A, but growths will be much larger, healthier, and will last longer. D. ‘ Tank-water ” sterilized. A fair growth of the inoculated species, but the total growth will not be as great as in C; the diatoms will retain their normal appear- ance for some time. E. ‘ Outside water” + Miquel’s solutions A and B, sterilized. Best culture in series, both in quantity and quality. The diatoms will remain normal and healthy for a very long period. F. “ Outside water” sterilized and treated with Animal Charcoal. Fair growth, especially at first; diatoms will soon grow pale and become exhausted ; better than D. G. “ Tank-water ” sterilized and treated with Animal Charcoal. As F, only growth will be slightly greater and will last considerably longer. Third best in series. H. ‘ Tank-water” treated with Animal Charcoal and filtered through Berke- . feld filter. This will usually be the second-best culture in the series, but the difference between this and G will only be slight. K. ‘Outside water” treated with H,0O,. This will most resemble F, but will not be quite so good. L. “'Tank-water” treated with H,O,. A distinct improvement over K. This medium is rather variable, and in some cases the growth obtained has been quite equal to F, if not better. 436 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. B. EXPERIMENTS WITH A VIEW TO DETERMINING THE CONDITIONS WHICH UNDERLIE THE SUCCESSFUL CULTURE OF DIATOMS. The attempt to make cultures of diatoms for use as food, when rearing pelagic larvee, led naturally to an effort to determine the best culture medium and the most favourable conditions for the rapid and continuous growth of diatoms. Before success can be attained in this direction exact knowledge as to the nature of the essential food-stuffs— and in fact as to the general physiology of the Diatomaceze—is necessary.* Numerous experiments, extending over the last three years, have been carried out, with a view to obtaining such knowledge, and the results, though still by no means complete or conclusive, are perhaps worth recording. A great difficulty which has to be met in carrying out such investi- gations on marine diatoms is caused by the fact that, when sea-water is used as a basis for the culture media, we are dealing with a solution of a very complex and very variable character, the exact nature of which it is extremely difficult to determine. The most direct method of research, namely, chemical analysis, has not proved of much service, owing to the uncertainty and in many cases impossibility of accurate determinations, in sea-water, of such minute quantities of substances as those upon which the growth of plankton diatoms has been found to depend. We have had, therefore, to rely, for the most part, on the lengthy and tedious process of analysis by “trial and error,” the experiments being largely conducted on lines suggested by Liebig’s well-known “Jaw of minimums” (Pfeffer, vol. i, p. 413). The ideal at which we aim is to find a culture medium, with artificially prepared sea-water as its basis, such that the absence, or diminution in quantity, of any one of its constituents would have a profound effect upon the growth of diatoms in it. Whether the conditions regulating growth in such a medium would be at all comparable to the natural conditions of life in the sea is a question that would have to be decided by experiment, but in any case this could be made a starting point for much more definite research than has yet been attempted. Up to the present time we have not, unfortunately, succeeded in finding such a culture medium. Throughout the work we have had very great difficulty, in spite of much care and many precautions, in obtaining consistent results. It may even happen that, in two flasks containing the same culture medium, inoculated with the same culture of diatom and standing side * For general references to literature see Bibliography, especially Miquel (12), Richter (18). ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 437 by side, under exactly identical conditions, as far as can be recognized, quite different degrees of growth will be observed. All experiments must therefore be frequently repeated before entire confidence can be felt in any conclusions which they seem to indicate. It must be remembered, also, that in all the persistent cultures of diatoms that we have used, bacteria have probably been present, and this fact has probably had some influence on the result. Unfortu- nately our attempts to obtain absolutely pure cultures have not met with success. Methods. In carrying out the experiments to be described in this section the procedure has been as follows :—AIl media have been pre- pared from sterile sea-water, and sterile vessels and instruments have always been used. The cultures have usually been made in. 60 cc. of liquid, in short-necked, wide-mouthed flasks of 125 ce. capacity. When a number of cultures were to be compared, the flasks were kept stand- ing in a row together in such a way as to keep the physical conditions as similar as possible. Control cultures in standard media were in- cluded in each series, so that results from different series could be com- pared by reference to the controls. The various media were inoculated from a persistent culture of a species of plankton diatom, which in the great majority of cases was Thalassiosira decipiens (p. 460). When pre- paring the different media the methods used were, as far as possible, identical, and although only about 60 cc. was needed for a culture, a litre was made up, so that errors due to measuring very minute quanti- ties might be avoided. The media were all freshly prepared for each comparative series of cultures, the same sample of sea-water being used, when the basis of any two or more was the same. Comparative esti- mates of the amount of growth in the different cultures were made by eye alone. Any difference between amounts of growth that has been described here as appreciable has always been accompanied by a marked difference in appearance to the eye on holding the cultures up to the light. A few drops from each culture were also, from time to time, examined microscopically as a test of the quality and purity of the growth. The sea-water employed. The sea-water employed as a basis for the culture media has been either (1) “ outside water” or (2) “ tank-water.” A general description of these will be found on pp. 429-431. An accurate chemical analysis of both types of water would probably make clear many difficult points, but, as already pointed out, no chemical methods of sufficient delicacy have yet been devised. 438 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. We have seen that if we compare “ tank-water,” 1e. water from the closed circulation of the Plymouth Aquarium, with off-shore sea-water in situ, a most obvious difference is the much increased density of the jarger forms of animal life in the former, combined with the almost complete absence of plant life. Hence the concentration of excretory products in the tank-water must be very much higher than in outside water. Other factors, such as increased bacterial action, artificial aeration, ete., in tank-water, must also be taken into account (ef. Vernon, 58; Smith, 56). There seems to be direct evidence to show that the concentration of nitrates, possibly due to the action of nitri- fying bacteria on the products of excretion, such as urea, ammonia, etc., is considerably higher in the tank-water, and the presence of soluble organic matter, in concentrations never met with in the sea, can almost certainly be assumed. It is probably due to the presence of these nitrates and soluble organic substances that sterilized tank-water is a much better medium in which to grow diatoms than sterilized out- side water (see p. 435). The constituents of Miquel’s solutions. It has already been stated that no better medium for the culture of plankton diatoms has been found by us than the solutions recommended by Miquel, although these solu- tions may be modified and simplified in various ways with equally good results. The formule recommended by Houghton Gill give very similar cultures. The essential features of Miquel’s and Houghton Gill’s methods, when adapted to sea-water, are the same. Miquel’s solution A, and Gill’s solution 2, can both be replaced by a solution of potassium nitrate (p.427). Again, Miquel’s solution B and Gill’s solu- tion 1 only differ in the proportionate amounts in which the various constituents are prescribed. The formule are :— Miquel’s sol. B. H. Gill's sol. 1. Na, HPO; 42H50..°. A Se cae eae 2 grm. Ca Cl, : s : oe Pe : ied Fe Cl, (syrupus) : : pee MCC O-o5, HCl (concentrated) . : ls PRG Cs : ls Water , ; : : Pe asONee: 00 ” Use l ce. per 1000. Use 3 ce. per 1000, The proportionate amounts added to equal volumes of sea-water ale ; Miquel’s sol. B. - H. Gill’s sol. 1. Na, HROp ie ; ; a0 amelie Cantliee® ; : ; cao i. he BuiClag eae eg ees ate HCl : ; : é ey ge : 6 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 439 Since cultures can be obtained with no appreciable difference by using media prepared by adding either of these solutions, together with Miquel’s solution A, to sea-water, a considerable latitude in the proportions of the salts present is tolerated. We must now consider what is the rdle of the various constituents in Miquel sea-water. The part played by any salt of a culture medium may be considered as being either, firstly, “nutritive,” or secondly, “protective.”* Under the first heading, any direct addition of food material must be included; under the second, any removal or neutral- ization of harmful substances, such as toxins and possibly bacteria, and any more remote effects, which, although influencing growth, do not directly enter into the metabolism of the plant. Our experiments have proved that solution A can be reduced to a simple solution of potassium nitrate+ without detriment (cf. p. 427), and that the amount of growth is, within limits, roughly proportional to the amount of KNO, added, as the following experiment shows :— Inoculated from persistent culture of Thalassiosira decipiens. A. Normal Miquel sea-water. Growth as usual. B. Ditto, but only one-half amount of sol. A. Good growth at first, but exhausted sooner than A, C. Ditto, but 24 times amount of sol. A. Was slower than either A or B at start, but afterwards was better than A or B and lasted longer. D. Ditto, but five times amount of sol. A. As C, but in greater degree. Considering the nature of the substance added, and its already well- known action in plant metabolism, these results, coupled with the fact that exhausted cultures can often be regenerated by the simple addi- tion of nitrates (see below, p. 444), are quite consistent with the assumption that sol. A is simply nutritive in action. The concentra- tion of nitrates in natural sea-water is so low (Brandt, 47) that the amount available in a culture of untreated water very soon becomes completely exhausted, and it is this deficiency that sol. A probably corrects. Considering now the action of sol. B, it must first be observed that increased concentration of nitrates alone will not explain the whole _ * Loeb, Zhe Dynamics of Living Matter (New York, 1906), p. 77. + For the sake of convenience, the expression sol. A will be used throughout the rest of this paper to indicate a simple solution of potassium nitrate (5 per cent) and sol. B to indicate Miquel’s phospho-ferricalcic solution (p. 423). Unless otherwise stated, the amounts of each added to 1000 cc. sea-water will be normal, i.e. 2 cc, sol. A and 1 cc, sol. B. NEW SERIES.—VOL. VIII. NO. 5. Marcu, 1910. mst 440 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. action of Miquel’s solutions, for no increase in growth is obtained when nitrates or sol. A only are added to sea-water. To illustrate this point an account of an actual experiment may be given :— Inoculated with Thalassiosira decipiens. A. Normal Miquel sea-water. Good strong culture, in every way normal. B. Outside water sterilized. Small growth at first ; very soon exhausted. C. Ditto+sol. A. No improvement over B. D. Ditto+sol. B. Fair growth. Great improvement on B and C, but exhausted considerably before A. E. Tank-water sterilized. Appreciably better than B, but growth not large. F. Ditto+sol. A. Not even as good as E. G. Ditto+sol. B. Next best in series to A; lasted longer than D, and had better colour, To generalize, no improved culture is obtained with sol. A alone, but a fair, though not very lasting, growth can result from using sol. B only. The action of sol. B is to some extent obscured by the fact that, when this solution is added to the alkaline sea-water, a precipitate is formed. This precipitate is at first white, but, on heating or stand-— ing for some time, it becomes greenish yellow. We are indebted to Mr. D. J. Matthews for the following analyses. Ten litres of normal Miquel sea-water were prepared, and the pre- cipitate was collected on a filter paper washed and dried at 100° C. Weight of dry precipitate from 10 litres = 0°'2949 grm. Analysis of Dry Precipitate. Per cent. 12) a eae ee Memon are AME ETE eis Fe Oi (OTC Ue we Re SE sae rae aoe =. Pe cae EEO) ic. : ; 5 . 24.86 100-16 Or, the precipitate from 1 litre of normal Miquel sea-water contains :-— POn: ; : ; . 00777 grm. PesQauvia ata Re Mme) chelate ete aes ame CaO . : : ; : #300225) oe ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 441 An analysis of 1 ce. Miquel sol. B, the amount added to 1 litre Miquel sea-water, gave :— ig (Os ; : : ; . 00825 grm. FeO, : ; : : - Ui0oe oe Cady. : : 3 : po OA ee Comparing these figures, it seems probable that, when added to sea- water, all the iron in sol. B is precipitated, and a certain amount also of the phosphate and calcium. The additive effect on the sea-water is therefore a slightly increased concentration of phosphate and calcium. An analysis of a sample of tank-water for phosphorus, before and after treatment with sol. B (1 cc. per thousand), gave the following figures :— Tank-water . : . } mgerm. P per litre = -00163 grm. P,0, Tank-water + sol. B (without precipitate) a ere; 4s jer O0468' 5, Ee It will be noticed that the figures from the different analyses do not agree very well. This is probably due to the fact that different samples were used for analyses in each case, and also to the fact that the solutions were made up in the ordinary way, without any special precautions, volumes, for instance, being measured in cylindrical glasses, pipettes, etc. Cultures were tried in sea-water containing the Rornal amount of sol, A, plus the normal constituents of sol. B, less all the iron and less the amount, of phosphate that would combine with the iron to form basic ferric phosphate (P,0;2Fe,0,12H,O). This solution should have very nearly the same chemical composition as normal Miquel sea-water from which the precipitate has been removed. Successful cultures could not, however, be obtained in it. Neither could cultures be grown in sea-water to which had been added the normal amount of sol. A and 1 mgrm. P (as sodium phosphate) per litre. To ascertain the effects of the different constituents of sol. B, experiments were carried out with separate solutions of these con- stituents, each of the same strength as in Miquel’s formula. Different combinations of these solutions were added, together with sol. A, to sterilized sea-water, and the resulting media were inoculated in the usual way. It was found necessary to repeat these experiments a great number of times, as the results obtained were rather contra- dictory. To illustrate the methods used, a list of the different media, and notes on the cultures obtained in them, are given below. These media were inoculated from cultures of Thalassiosira decipiens, and the 442. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. cultures were kept under observation for at least four months. Series were made as uniformly as possible, and controls in standard media were included in each. The strength of the various solutions used in these experiments was the same as in Miquel’s formula. A, Outside water + sol. A+sol. B (normal Miquel sea-water), _. First control. B. Outside water + sol. A+ Na,HPO, sol. + FeCl, sol. + CaCl, sol. Second control. Good normal cultures were always obtained in these two controls. C. Outside water + sol. A+ Na,HPO, sol. A very uncertain medium. Sometimes no growth has been recorded and at other times a fair growth results, but these cultures are never equal to normal Miquel. D. Outside water + sol. A + FeCl, sol. Occasionally a very small growth has been obtained, but at the best it is very poor. E. Outside water + sol. A + CaCl, sol. About equal to D. F, Outside water + sol. A+ Na,HPO, sol. + FeCl, sol. Uncertain as C ; no cultures have been obtained equal to the best in C. G, Outside water +sol. A +Na,HPO, sol. + CaCl, sol. Some cultures very nearly equal to the controls have been obtained in this medium. H. Outside water + sol. A+ FeCl, sol. + CaCl, sol. Poor, about equal to D. Analysing the above results, we see that— (1) None of these modifications of sol. B give results equal to sol. B: itself. (2) The best result is obtained from the combination of the phosphate: and calcium chloride solutions. (3) Of the solutions used singly the phosphate is the best, the iron and calcium chloride being about equal. (4) The addition of FeCl, to Na,HPO,, or the addition to CaCl, to FeCl,, does not improve the medium to any extent. Experiments were also made to determine whether the precipitate thrown down in sea-water by Miquel's sol. B, itself had any influence on culture media. A quantity of this precipitate was prepared, filtered off, and then added to outside sea-water+sol. A (nitrates). A small growth was obtained, which was a distinct improvement on the control without the precipitate, but exhaustion soon set in. Further discussion of the mode of action of sol. B, and as to whether that action is purely nutritive, or partly nutritive and partly. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 443 protective, is better postponed until a later section, after the action of animal charcoal and other substances has been considered (see p. 455), Animal Charcoal and Peroxide of Hydrogen. The most successful culture medium for plankton diatoms, next to Miquel sea-water, is that prepared from animal charcoal (ef. p. 435). Animal-charcoal water gives at first almost as good cultures of plankton diatoms as Miquel sea-water, but the tendency to paleness and exhaustion appears much sooner. The best cultures were obtained in “ Berkefeld water,” that is, tank-water from the Plymouth Aquarium treated with powdered commercial animal charcoal and filtered through a Berkefeld filter. Tank-water as a basis for animal-charcoal water is very much better than outside water, probably on account of the higher con- centration of nitrates, ete. There is a very striking resemblance between the effect of animal charcoal and of Miquel’s sol. B upon sea-water used for diatom cultures, and the growths obtained by using tank-water+sol. B and tank animal-charcoal water are very similar in character. If Miquel’s sol. A is added to animal-charcoal water, there is a great improvement, both in the colour and quantity of diatom growth, and in the case of Thalassiosira decipiens the chains are long and well formed. With animal - charcoal water+sol. B, on the other hand, practically no growth was obtained. It is possible that a certain amount of phosphate, and perhaps of calcium, from the animal charcoal, goes into solution and serves as a “nutritive” material for the diatoms. But we are inclined to think that its chief action is “ protective,” and due to its power of occluding gases, such gases being in a state of higher chemical activity than under normal conditions.* As was explained in a previous section (p. 454), the possibility that the action of animal charcoal might have some sort of effect com- parable to oxidation, led us to experiment with hydrogen peroxide. Fair growths of diatom could be obtained in sea-water prepared in the manner described, but they always showed a tendency to rather rapid exhaustion. As in the case of animal-charcoal water, tank- water proved a much better basis for treatment with H,O, than outside water. Reviving Exhausted Cultures. Several experiments were carried out with water from old, exhausted cultures. The sediment was filtered * Against this view would seem to be the fact, that when powdered cocoanut charcoal, which has a still higher power of occluding gases, was used in the place of animal char- coal, very poor cultures were obtained. 444 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. off, the filtrate was sterilized by heat, and then treated by various methods. In one typical experiment the following was the result :— Water from an exhausted culture of Shelefonema costatum in Miquel sea-water, reinoculated with the same diatom :— A. Filtered and sterilized. No growth obtained. B. Ditto +sol. A (nitrates only). Good culture, but did not last very long; further addition of nitrates made no improvement. C. Ditto + sol. B. No growth. D. Ditto +sol. A+sol. B. Very good growth, lasting considerably longer than B. K. Ditto +an. char, No growth, Exhausted cultures in animal-charcoal water gave the same general results on treatment and reinoculation. In an old culture of Biddul- phia mobiliensis in outside water+sol. B only, which was in a very exhausted condition (nine months old), the addition of KNO, gave a very rapid regeneration, and the diatoms became of normal colour and form. This renewed growth, however, did not last very long, and a further addition of KNO, did not give any result. The addition of sodium phosphate also failed to stimulate growth. The same rapid regeneration, on the addition of potassium nitrate, has been obtained with almost every medium, but a second attempt has always failed. Silica. A very noticeable character of the true plankton species of marine diatom is, that their skeletons are very markedly less silicious. than the great majority of other forms. Their valves are only feebly marked, if at all, and they will not stand the vigorous treatment of cleaning with acids and heat that is commonly used in the case of fresh-water diatoms. In cultural forms, this absence of silica is still more obvious, and no marking can usually be seen on even those forms which, under natural conditions, are the most silicious, e.g. Coscinodiscus excentricus. Deformed and distorted frustules are the rule in certain stages of growth in our cultures, and it is often very hard to make out more than the thinnest coating of silica. It is quite probable that this deformity can be accounted for simply by the absence of a strong silicious skeleton. Asa rule, the more rapid the growth, the more teratological forms will be found. In untreated outside water little deformity will take place, but in normal Miquel, where very rapid growth takes place, the diatoms may assume almost ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 445 any conceivable shape. The form of the frustules tends to come back to the normal again, when the culture is well started, and in old stages the majority will be perfectly formed, although small and pale. It was found that the addition of silica (in early experiments as fragments of potassium silicate) was, as far as could be judged, immaterial, which fact led to the conclusion that a sufficiency dissolved out from the glass flasks in which the cultures were kept. During rapid growth, it is possible that the silica does not dissolve out fast enough to supply the demand, although it is also possible that diatoms, during rapid division, cannot absorb silica and form a perfect skeleton, even when the supply is abundant. Richter (18) has proved the necessity of either CaSi,O, or K,Si,0, for the growth of Nitzschia palea, grown in pure cultures. We tried the addition of silica in various forms, and in one instance, in a culture of Coscinodiscus excentricus, to which a little precipitated calcium silicate had been added, the uniformity and markings of the valves were much more regular than in the control. The presence of a trace of pure, dialysed silica, also, in one experiment, gave an im- proved regularity of form, but the quantity or rapidity of growth did not seem to be affected. No sign of regeneration could be obtained in exhausted cultures by the addition of silica. Organic Infusions.—Miquel recommends the use in culture media of infusions of organic substances such as bran, straw, diatom broth, etce., in addition to the saline solution. He does not make it quite clear if he ever dispensed with them at all. In his general directions, he certainly states that the addition of both saline and organic nutrient material is necessary. As would be expected from the general metabolism of plants, the saline constituents are sufficient for growth. At the same time, excellent cultures have been obtained from dilute organic in- fusions, both with and without the addition of Miquel’s sols. A and B. About a square inch of Ulva was boiled in 600 ce. sea-water for half an hour, cooled and filtered. In this medium an excellent growth of Coscinodiscus excentricus in one case, and Biddulphia mobiliensis in another, was obtained, the growth lasting for some considerable time. Infusions, made in the same way from a small piece of fresh fish, gave the same results, and although growth was rather slower at first, the final result was, if anything, slightly better. As Miquel points out, these infusions must be made very dilute, otherwise growths of bacteria, moulds, etc., will completely swamp the diatoms. Karsten (7), in some interesting experiments, showed that Nitzschia palea (Kutz), W.Sm., could be made to alter completely its mode of nutrition. On placing this diatom in organic nutrient solutions, it lost all chloro- 446 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. phyll and became colourless, but in saline media the chlorophyll would not regenerate, and the nutrition change back from heterotrophic to autotrophic.* Of course, with our infusions, it cannot be said that the diatoms were necessarily feeding on dissolved organic material, as some neces- sary, saline, nutritive materials could have dissolved out from the weed or fish. If the former is the case, it might explain the superiority of tank-water over outside water, since the tank-water must contain a much higher percentage of organic substances in solution. If an alternative mode of nutrition autotrophic or mixotrophic could be proved, especially in the case of the “bottom” forms of diatoms, a great many phenomena could be explained, but the evidence is as yet far too slight to warrant any such assumption. Artificial Sea-water.—As we have explained in a previous section, the ideal aimed at, in this part of our work, has been to obtain strong growths of diatomaceae in purely artificially prepared solutions of simple salts. If this end could be satisfactorily attained, the diffi- culties due to the unknown and variable composition of natural sea- water at once disappear. According to van ’t Hoff (35) sea-water is a solution containing salts in the following molecular concentrations :— NaCl 100-0, KCl 2-2, MgCl, 7:8, MgSO, 3-8, CaCl, 1-0 (varies). Using these molecular concentrations, a sea-water of any desired salinity can be prepared. The chlorine content of average Atlantic water is about Cl=19-4, and samples of artificial sea-water were pre- pared with the same chlorine value, thus :— NaCl ; 5 ; ; : Pin DOO KCl; 4 : : 3 : : -75 MgCl, . J : ’ : ' 3-42 CaCl, : F E : : , 51 MgSO eZ : ’ A : ; 5 2-10 Double-distilled water . : . 966-47 1000-00 To make this solution comparable to natural sea-water, the “alka- linity” must be raised by the addition of an alkali such as Na,CO,. After the importance of “alkalinity” as a factor had come before our notice, 2°4 ce. M/, Na,CO, was always added to the above solution in order to make the amount of base in equilibrium with CO, equivalent to the usual 40 mgrm. OH °/,, (p. 450). * Cf. Zumstein, Zur Morphologie u. Physiologie d. Euglena gracilis. Leipzig. 1899, ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 447 The only success we attained with artificial sea-water as a basis for culture media was with four isolated cultures in one of our earlier experiments. Two of these were cultures of Coscinodiscus excentricus in artificial sea-water + Miquel’s solutions A and B. The two cultures were identical except that one was in an ordinary Bohemian glass flask and the other in a “resistance glass” flask. No difference be- tween these two could be seen. The growth obtained in both was in every way equal to normal Miquel sea-water, and is still fair, although over two years old. The other two successful cultures were growths of the same diatom in the same media, plus a small quantity of weed infusion, made by boiling up a small piece of Ulva in artificial sea- water. These gave just as good results, but the addition of unknown factors from the weed detracts from their general interest. In spite of frequent attempts, over fifty in number, we have not been able to repeat this experiment, which may possibly be due to some accidental impurity in the salts or distilled water from which the successful media were prepared. Alkalinity, Tornée (43) and Dittmar (33) were the first to investigate the fact that sea-water showed on analysis an apparent excess of base over acid, which excess they termed “the alkalinity of sea-water.” Dittmar defines the alkalinity of sea-water as “a measure of its potential carbonate of lime,” but this definition, and his supposition that this excess of base combines directly with dis- solved CO, to form carbonates and, further, but only in very small proportion, bicarbonates, is liable to give a quite erroneous idea of the state of equilibrium actually occurring in the ocean. For, as Fox (34) has shown, “sea-water reacts.7 situ very nearly neutral, and actually just slightly more acid than distilled water.’ This is due to the fact that sea-water always contains a considerable quantity of dissolved CO,,. If a salt solution with neutral reaction, that is containing H* and OH’ ions in concentrations equal to one another and the same as for pure water, be exposed to an atmosphere containing CO,, a definite amount, depending on pressure, temperature, and salinity, would go into solution. This CO, would combine with water and form the very weak acid H,CO., which would ionize with the formation of the free H® ions thus :— H,CO, ’2 H*® + HCO’,. (HCO’, 2 H*+€0",). The second stage of dissociation is so small as to be negligible. The concentration of H* being now increased, and OH’ decreased, the 448 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. solution would have an acid reaction. The actual amount of CO, thus dissolved would always be small; for instance, a salt solution of strength Cl=20-00 (average Atlantic water Cl=19°4) will at 10°C. dissolve about -3 ce. CO, per litre from an atmosphere containing 3°/,,, CO, (about normal). But the ocean is found to contain very much greater quantities than this, 60 cc, or two hundred times this amount, being a not unusual figure for the total CO,. The difference between this amount and the ‘3 ce. or so dissolved by the neutral salt solution, as above, is kept in equilibrium with the 3°/,,, CO, of the atmosphere, by the amount of “excess” base equivalent to the amount of acid neutralized when an acid such as HCl ig added to sea-water in excess. If a solution identical with sea-water but absolutely free from CO, (a practical chemical impossibility) could be obtained, then there would be present an excess of base over acid, and consequently an excess of OH’ ions over H”° ions, and an alkaline reaction. On exposing such a solution to the atmosphere, CO, would go into solu- tion, ionize, and the H° ions thus set free would react with the OH’ ions, due to the excess base, to form water. And this reaction would continue to take place, on more CO, dissolving, until all the excess OH’ ions were neutralized, at which point the solution would react neutral. Now, as before with the neutral salt solution, a further small amount of CO, would go into solution, bringing the solution into equilibrium with the atmosphere, and the excess H* ions thus formed would give an acid reaction. The final result would be a Solution exactly identical with natural sea-water. The total CO, found in sea-water can be considered as existing in two parts: the larger part in equilibrium with free base, its amount depending on temperature, pressure, and alkalinity ; the smaller in equilibrium with the partial pressure of CO, in the atmosphere, its amount depending on temperature, pressure, and salinity. Although sea-water in sitw has an acid reaction, it still maintains the property of being able to neutralize a certain amount of any acid stronger than H,CO,, that is any acid which, on dissociation, forms a higher concentration of H* ions; for the stronger acid will turn out the H,CO, in equilibrium with the “excess base” and CO, will be evolved. In consideration of these points a less confusing definition of the “alkalinity of sea-water” would perhaps be a@ measure of its potential capability of neutralizing a strong acid* with the evolution of CO). This can be conveniently expressed, as is usual, in mgrm. OH °/... Some of our earlier experiments seemed to show that “alkalinity” was a factor of considerable importance for the successful growth * Such as HCl, with a high degree of ionization. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 449 of cultures of plankton diatoms; so an attempt was made to analyse the various samples of water both before and after treatment as culture media. The method adopted was a modification of that used by Tornée and Dittmar. Solutions of NaOH and H,SO, of strength N/;9, by intention, were made up and stored in 5-litre “aspirator” bottles. Two accurately graduated burettes standing side by side were connected to these by tubes, so that they could be readily filled by gravity. All air inlets to burettes and stock bottles were fitted with tubes of soda lime. A standard solution of Na,CO, of exactly known alkalinity, approximately that of average sea-water (40-00 mgrm. OH */,.), was prepared by diluting down from a N/,, solution, all operations being performed by weighing. These standards were stored in stoppered bottles of the fairly insoluble dark green glass, but those that had been kept for any length of time were not trusted, fresh standards being prepared. On analysis these standards agreed with one another to well within ‘1 mgrm. OH’/,.. The water used for diluting the standards was distilled water from the laboratory still, redistilled in all-glass apparatus with potassium bichromate and sulphuric acid. When carrying out an analysis, equal volumes (about 100 cc.) of sample and standard were measured out into Jena glass Erlenmeyer flasks with a Knudsen automatic pipette. The specific gravity of each was determined by weighing in a 25 cc. pyknometer. Sample and standard were then titrated by running in acid from the burette and back titrating with alkali, using a 1 % alcoholic solution of aurine as an indicator and keeping the liquid boiling. The acid to alkali equiva- lent was determined by titrating a pipetteful of double-distilled water in the same manner. The mean of at least four readings was always used. Let N and n be number of burette divisions of alkali equivalent to standard and sample respectively, and D and d their density at the time of pipetting out. Then if A is the alkalinity of the standard and X the required alkalinity of sample :— Dn Nd Since all operations were carried out at the same room temperature, no corrections for temperature are necessary. In spite of the greatest care consistent results could not be obtained by this method of analysis. A sample analysed against the same standard would sometimes give results varying as much as 0°5 mgrm. and occasionally 1°0 mgrm. OH %. The work on indicators by Salm (42) and its application to this question has only recently come to our notice, and it is our intention to experiment on this in future research. X=A 450 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. The figures quoted below as the results of analyses have been rounded off as whole numbers, since their interest lies in their comparative rather than their absolute value, for convenience they are quoted as “allalinities,” although we are fully conscious that the methods used do not warrant this assumption, and that their actual chemical significance is still obscure. The mean value for “outside water” was found to be fairly constant at 40°0 mgrm. OH°/,., which figure agrees with results obtained by others for average ocean water. Samples from the aquarium tanks never gave as high figures as this, the average being approximately 37°09 mgrm, OH*/,... From this it seems that the amount of base in equilibrium with CO, in tank-water is appreciably less than in outside water. A series of thirteen samples taken from seven miles beyond the Eddystone to well inside the Cattewater (an inner tidal harbour near Plymouth) showed a gradual lowering of the alkalinity from the normal 40, to 38 mgrm. OH°/,, as the water became more estuarine and polluted. The addition of Miquel’s sol. B to sea-water was found, on analysis, to reduce the “alkalinity” by an amount equivalent to 10 mgrm. OH */,, or more. The 1 ce. sol. B added to a litre of sea-water, in itself contains a certain amount of free acid, equivalent to less than 4mgrm. OH’/.... But this reduction of alkalinity cannot be accounted for by the addition of free acid alone, because if only a quarter of the amount of sol. B is added, the alkalinity of the sample will be found to be, if anything, only very slightly higher. Also, if the various constituents of sol. B are added as separate solutions, thus obviating any addition of free acid, a reduction equivalent to about 6 megrm. OH °/,, is still obtained. The presence of ferric chloride in sol. B gives a possible explanation of this phenomenon. If a solution of ferric chloride is added to a solution of a soluble carbonate, a reaction, which can be expressed by the following equation, takes place :— 3 R,CO,Aq. + Fe,Cl,Aq. = 6 RCI.Aq. + Fe,0,Aq. +3 CO,,. When the ferric chloride is added to sea-water, the final result will be that a certain amount of the “excess base” which was in equi- librium with CO,, will then be in equilibrium with the chlorine, available on the precipitation of hydrated ferric oxide, with a consequent liberation of CO,, and a reduction in “alkalinity” will, therefore, take place. An analogy between the actions of Miquel’s sol. B and animal charcoal can be seen in the fact that water treated with animal charcoal also shows a reduced “alkalinity,” the amount being very variable in different samples. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 451 Sea-water treated with H,O, also showed a lowering of the alka- linity, but in a much less degree when, as usual, minimal quantities were used. Control experiments on double-distilled water, which had been treated with these substances, were tried, but great difficulty was found in obtaining an end point with the indicator. As far as could be judged, distilled water treated with sol. B (quantities as with sea- water) showed a negative “ alkalinity,’ equivalent to about 8 mgrm. OH’/.., and in the case of animal charcoal a positive alkalinity equivalent to 6 mgrm. OH*/,., but the colour change was so slow that these results are only the roughest estimates. The possibility that the above results are due to some effect on the indicator, which entirely cloaks the true alkalinity, must always be taken into consideration. Before any attempts at analysis had been made, the probability that considerable differences might be found in the alkalinity of the various media had presented itself. Improvement in the growth of diatom cultures was found to result from the purely empirical addition of NaHCoO,, this result being most marked in normal Miquel sea-water, outside water + sol. B only, and Berkefeld water. No growth could be obtained in either tank-water or Miquel sea-water to which had been added 1 cc. HCl (pure, concentrated) per litre, but on again raising the alkalinity of the latter by the addition of NaHCO, or KOH good normal growths resulted. Richter (18) and H. Gill (5), also, both state that a weak alkaline reaction is necessary for the growth of diatoms. In our most recent experiments, all the media have been analysed for alkalinity, and those given in detail below illustrate the importance of determining this factor. Cultures of Thalassiosira decipiens were made in the following media :— A. Tank-water. Control. Poor growth, hardly normal. Later, good growth of minute forms, ete. B. Tank-water treated with cold commercial animal charcoal and filtered. Very good growth indeed. C. Tank-water treated with cold pure an. char. and filtered. Very poor growth, comparable to A without minute forms. D. Tank-water treated with pure an. char. as in C, but the an. char. was added red hot. Fair growth, much superior to C, but not up to B. The sample of pure an. char. used here had been previously found to give very poor results, and it was also quite contrary to our experience that any improvement in growth should be obtained by adding it hot. 452 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. But if we examine the results of analyses of these media for alkalinity a probable explanation presents itself. The following figures are only comparative :— A—38 mgerm. OH*/.. (used as standard). B—37 sa, 3 (higher than usual). C—16—S,, i (very low indeed). D—34 _,, a It will be seen that the amount of growth in each treated sample follows the alkalinity very closely. Solutions of Na,CO,, NaHCO; and HCl were made up, so that 4 ce. of any one contained an amount of acid or alkali equivalent to 10 mgrm. OH. From these a series of normal Miquel sea-waters of different alkalinities were prepared. Cultures of Zhalassiosira de- cipiens were grown in these media. A. Normal Miquel sea-water. Control. A= 32-7 mgrm. OH °/,.. Perfectly normal growth. B. Ditto+4 ec. Na,CO, per litre. A=41'7 mgrm. OH*/,, (= +9°0).* No difference between this culture and A. C. Ditto+8 ec. Na,CO, per litre. A=50-2 mgrm. OH */,, (= + 17°5). Best culture in series in quality and quantity. D Ditto+4 cc. NaHCO, per litre. A=42-4 mgrm. OH*/,, (= +9°7). Slightly better than control. E. Ditto+8 ec. NaHCO, per litre. A=51:'5 mgrm. OH*/,, (= +18°8). As D. F. Ditto +4 cc. HCl per litre. A=22°2 mgrm. OH */,, (= —10°5). Fair growth but never up to control, exhausted much sooner. G. Ditto+8 cc. HCl per litre. A=11:1 mgrm. OH*/,, (= —21°6). Poorest in series. Except in the cases where the alkalinity was lowered by the addition of HCl, the results obtained from this series were not up to expecta- tion. Nevertheless the majority showed a distinct improvement from increased “ alkalinity” and in C, where the alkalinity had been raised 175 merm. OH*/,,, this improvement was very marked. Another point illustrated by cultural experiment is that in two samples of an. char. water, one with “outside” and the other with “tank-water” as a basis, the amount of growth in the latter consider- ably exceeded that in the former, and at the same time it was found that, with the tank-water, the alkalinity had not been reduced to the same extent as in the case of the outside water. How far apparently anomalous results, which have so frequently * Figures in parentheses are difference in alkalinity from control, in mgrm. OH °/,.. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 453 occurred in our experimental work, could be explained by unforeseen changes in “alkalinity,” can only be answered by future research. Salinity.—The salinity (or amount of salts dissolved in a litre of sea-water) of the outside water used in these experiments only varied between small limits, S=34'5 -35°5°/,,.. The salinity of “ tank-water ” is also fairly constant, the average being about S=34:9°/,,; water is only pumped up into the reservoirs at high water, spring tides, and unless the salinity on analysis is well above S=34:'5°/,, no water is taken. Experiments to show what effect salinity pure and simple had on the growth of diatoms were undertaken. Samples of sea-water of various salinities were prepared by diluting down “outside water” with double-distilled water, and by concentrating “outside water” by slow evaporation. Two litres of “outside water” S=34:°9 were evaporated down to the bulk of one litre, giving a 507/* concentra- tion. Miquel solutions 4 cc. A, 2 cc. B, were now added, and the solution was divided into ten culture vessels, 20 cc. in each. Double- distilled water was added, 2 ce. to the first, 4 cc. to the second, 20 ce. to the last, so that a series of media were obtained, varying in salinity from normal to nearly 507% concentration, each containing the same amount of Miquel’s nutrient solutions. These were inoculated from a mixed culture of Skeletonema costatum, Biddulphia mobiliensis, and Coscinodiscus excentricus. A good growth took place in all except the two with highest concentration. Of these two, the last remained practically sterile and the growth in the other was very poor. The limit of concentration, therefore, seems to lie between 35 and 407. In the same way series of lowered salinities were prepared, and cultures of the same diatoms were grown in these. Dilution up to 100% did not seem to make any difference at all in the quantity or quality of growth. In a series extending the dilution to 2007 even in the cultures of lowest salinity, a fair quantity of growth took place. The range of salinities covered by the various series was S=12"/,, to S=60°/,, and within these limits no effect on growth could be observed, except in the very highest, where a distinct deterioration was noted. An attempt to grow Coscinodiscus excentricus in tap water + Miquel’s solutions was tried, and it was thought that some slight multiplication took place, although it was certainly not at all considerable. In- oculating a culture of normal Miquel sea-water from this after six weeks gave no growth. Light. Of all the factors controlling the rate of growth of a culture, * i.e. from every 100 cc. sea-water 50 cc. HO had been subtracted. 454 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. light seems to be by far the most important. Without light a culture soon dies off completely, showing marked signs of malnutrition very soon after having been placed in the dark, the brown pigment being the first to go, and later the chlorophyll. A culture (Thalassiosira) placed in the dark for five months was found to be completely killed, the diatoms being quite colourless. In cultures kept in bulbous flasks or any spherical vessel, the strongest and earliest growth always takes place at the side of the vessel away from the source of light, where the light will be found to be concentrated owing to the lens effect of a sphere of water. By painting a flask black on the outside up to the water-line of the medium, a very marked diminution in the rate of growth was obtained. The total growth was not affected, but depends on the available quantity of food-stuffs present. Experiments on the reaction of cultures to different rays of the spectrum, obtained by coloured glass, were tried, but no results obtained. Miquel obtained marked results with yellow light, but in our experience, with plankton diatoms, satisfactory cultures could not be obtained under these conditions. Temperature. The highest temperature which diatoms and allied forms can stand was about uniform for all the species tested, and lay between 35°-40° C. Cultures of the following species, viz. Asterionella japonica, Nitzschia closteriwm, minute naviculoid diatom, Pleurococeus mucosus, Chilomonas sp., were slowly heated in a water bath, and at every rise of 5°C. from 15°C. to 45°C., a few drops of the culture were pipetted out and a fresh flask inoculated. In all the flasks cultures were obtained where the heating process had not been carried above 35°C., but none in those where the temperature had exceeded this. In the earlier stages of experimentation the cultures of diatoms were kept in various places about the Laboratory, and so were under quite different temperature conditions. Those placed in the warmer situations, Le. near hot-water pipes, as a rule gave the most satis- factory results. In all the later work the cultures have been kept in one room, and an attempt has been made to keep the temperature of this room as nearly as possible constant at 15°C. A continuous record of its temperature has been kept by means of a recording thermograph, and no very great change of temperature has been noted. In a few isolated cases the temperature has dropped as low as 9°C., and in hot weather has risen just above 20°C., but these have only been for very short periods, the average temperature having kept remarkably constant. An apparatus in which flasks could be kept at ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 455 different uniform temperatures from 10° to 25°C., by means of hot air, was used, but no really satisfactory result could be obtained. About 17°C. seemed to give the maximum growth, and the cultures below this temperature were usually superior to those above. General Conclusions. The general conclusions to be drawn from the experiments described in this section, which were made with a view to determining the conditions that underlie the successful culture of diatoms, may now be discussed. Although the experiments have in- volved the making of some 750 different cultures, our conclusions on many of the questions raised are still indefinite, and much further work will be necessary before a satisfactory answer can be given to them. If we wish to obtain the maximum quantity of healthy growth of a plankton diatom, the diatom must first be obtained as free as possible from all other organisms, if not in a “pure” culture, at least in a “persistent ” culture. All culture media should be sterilized either by heat or filtration, and the experiments should be conducted under sterile conditions. Starting with normal sea-water as the basis for the culture medium, it seems to be first necessary to raise the concentration of the nitrates, and possibly also of the phosphates, in solution. But this simple addition of nutrient materials will not in itself suffice. Some other action, such as that exerted by Miquel’s sol. B, by animal charcoal, or by peroxide of hydrogen, seems to be imperative in nearly every case. The exact nature of this action we have not been able conclusively to determine. If the substance contained in sol. B were purely nutritive in character, we should expect that, when altera- tions in the amounts of the different ingredients were made, or when any one of the ingredients was omitted altogether, the differences in the quantity of growth would show a direct relation to the kind of modification introduced. But our usual experience has been that sol. B can be modified within certain limits, without producing any appreciable effect upon the resulting cultures, whilst if these limits are exceeded, there is an almost complete inhibition of growth. In supplying a necessary increase of phosphates, both Miquel’s sol. B and animal charcoal may and probably do act as “nutritive ” substances, but, since the addition of phosphates alone does not yield cultures comparable with those produced by either of these, and since, excepting phosphates, there is no possible common nutritive substance in their composition, we are led to conclude that, in addition to any nutritive effect, they must exert some other action. This view is supported by the results obtained by using H,O.. This substance cannot be directly “nutritive,” although it may be so indirectly, by oxidizing into useful NEW SERIES.—VOL. VIII No. 5. Maren, 1910. Dak 456 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. food-material substances which the diatoms are incapable of using in their metabolism, e.g. nitrites into nitrates. The absence of any increase in phosphates, when using H,O,, may possibly be the reason why better results were not obtained with this medium. The action which, in addition to any nutritive value, we must assume that sol. B, animal charcoal, and H,O, can all effect, would appear to fall into the class of “ protective” actions (p. 439). It is quite conceivable that, with different samples of sea-water, this “protective” action is not neces- sary in every case, and this would account for the anomalous results met with when using sea-water + nitrates + phosphates only, in which medium sometimes good cultures, but more often the reverse, are obtained. The effect of Miquel’s sol. B, animal charcoal, and H,O, on the “alkalinity ” of the sea-water, also points to some chemical change, which does not directly enter into the metabolism of the plants. It may be pointed out that the action of such substances as finely powdered carbon, and ferric oxide precipitates, has been shown to pro- duce a favourable effect on nutrient solutions used for the culture of certain higher plants, and it has been suggested that the beneficial action of these substances is the removal of toxic elements from the media (Breazeale, 3). Such removal of toxins would fall under our definition of “ protective” action. Of nutritive substances, other than those already mentioned, we have still to consider (1) silica and (2) dissolved oxygen and carbonic acid. Having regard to the conditions under which our cultures have been grown, Le. in glass flasks, the question of silica does not seem to enter into the problems which we have discussed. A few words must, however, be said as to the dissolved gases. Whipple (62) and Bald- win (44) have drawn attention to the observed relations, which are found in natural waters, between algal growths and the amounts of dissolved oxygen and carbonic acid. That these factors are of great importance cannot be doubted, but in our cultures it seems reasonable to suppose that the conditions of saturation of these gases are the same in all, since series of cultures in standard media, such as Miquel sea-water or Berkefeld water, can be set up with the certainty that, if not every one, at least a very high percentage, will give normal results. Of the purely physical factors, light is by far the most important. Within limits, the rate of growth in a suitable medium seems to depend directly on the intensity of the light (Whipple, 60). Absence of light, as would be expected, soon completely kills the diatoms. Temperature also seems to affect the rate of growth to a certain extent, but for those temperatures at which we have experimented it does not appear to alter the quantity of growth. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 457 Salinity, apart from the quantities of available nutrient materials, can be varied within large mits without appreciable effect on the diatoms. Il. MIXED CULTURES. In what has been said up to the present, we have been dealing with persistent cultures containing a single species of diatom, which are comparatively, if not entirely, free from admixture of other organisms, The study of cultures which contain a considerable mixture of organ- isms 1s not without interest. A number of experiments have been made on the following lines. About 10,000 ec. of water, taken at some distance from shore, was placed in a tall bell-jar fitted with a “plunger,” which keeps the water in constant movement. (Journ. Mar. Biol. Assoc., Vol. 5, p. 176). The water was treated with Miquel’s solutions in normal propor- tions, and a considerable quantity of plankton taken with a fine-meshed net (150 meshes to the inch) was added, say, 10 or 20 ce. of a moderately rich sample of tow-netting. The experiments were made during the spring and summer months, and the general course of events has been the same, with a certain amount of difference in detail according to the nature of the plankton present at the time. During the first two days the water often became cloudy, owing to the rapid multiplication of small flagellate infusoria, though this was not always the case. Plankton Copepods and other animals gradually died off, though some survived for as long as a week or ten days. The plankton diatoms, on the other hand, generally multiplied rapidly during the early days of the experiments, the first to become abundant in the body of the water being usually Skeletonema costatum, which at the end of a week might be so thick, that a number of chains could be seen in every drop of water examined with the microscope. Along with the Skeletonema were found other plankton diatoms, such as Lauderia borealis, Chactoceras (two or three species), Biddulphia mobi- liensis, Ditylium Brightwellii, and in nearly every case Thalassiosira decipiens. These latter diatoms were present in moderate numbers only, when the Skeletonema was at its height; but as the Skeletonema died down they increased in quantity. At the same time Nitzschia closterium commenced to appear, both amongst the precipitate on the bottom of the jar, and in the general body of the water. Small green flagellates often began to get numerous also at this stage. The true plankton diatoms were at their height about a fortnight after the experiments were started. At this time a great many diatoms of all 458 ON THE ARTIFICIAL CULTURE OF MARINE PLANKION ORGANISMS. kinds were to be found amongst the precipitate at the bottom of the jar, Asterionella japonica and Coscinodiseus excentricus being often numerous here. During the course of the next week, however, Nitzschia elosterium rapidly increased in quantity until, not only the sides of the jar were coated with it, but the whole mass of the water became thick and opaque. By this time the plankton diatoms had all disappeared, with the exception of those which may survive for a con- siderable period amongst the precipitate at the bottom of the jar. Bottom diatoms (Mavicula, ete.) had begun to grow on the sides of the jar, and small green and brown alge (Dlewrococeus mucosus, Ketocarpus, etc.) also appeared. Infusoria (Huwplotes and other smaller forms) then became numerous, and as the WVitzschia and bottom diatoms increased on the glass, large numbers of Amoebe made their appearance among them. The jars continued in this condition for many months, the alge becoming more and more predominant. From these experiments, as well as from instances of mixed cultures obtained in the course of our attempts to secure persistent cultures of single species of diatoms, it seems usual that, in a culture obtained by inoculating Miquel sea-water with plankton taken freshly from the sea, the true plankton diatoms are the first to develop in considerable numbers. Subsequently bottom diatoms and ale of various kinds become abundant, and the true plankton forms die out. A complete explanation of this sequence of events would probably be of a very complicated character, and we have practically no evidence from our experiments which bears very directly on the question. It would seem, however, that the early predominance of the plankton forms in the cultures would naturally follow from the fact that, in the plankton material used for inoculation, these plankton forms are numerous, whilst bottom diatoms and spores of alg are rare. The subsequent very great predominance of such a species as Nitzschia clos- terium may be due simply to a very much more rapid growth rate, though it is difficult to avoid the impression that the organisms which finally take possession of the cultures, are in some way directly inimical to those which they supersede, not merely by robbing them of their food-supply, but perhaps, also, by the production of toxic substances. This suggestion does not, however, give an adequate explanation of the essential facts concerning these organisms. We have to consider two sets of species: (1) the true Plankton form:, which flourish in the open sea and can be grown quite easily in the laboratory, provided the cultures remain pure; and (2) what we may call “aquarium” or “bottom forms,” which under experimental conditions invariably take possession, when present in mixed cultures, whilst the plankton forms. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 459 are killed off. Why is it that, although species of the second class are always present in small numbers in plankton taken from the sea, they are there altogether outnumbered by the true Plankton forms, whereas under conditions such as those of our experiments they invariably succeed in gaining the upper hand? What are the factors which determine the difference in behaviour of these two sets of organisms in the sea and in the culture vessels? The whole question offers a very fruitful field for further experiment. The evidence at present available is so slight that further discussion of it here is not likely to be of much service. The details of two experiments which we have made, bearing on the subject of mixed cultures, may, however, be recorded. A flask, containing about 1000 ce. of sea-water treated with Miquel’s solutions, was inoculated with approximately equal amounts of certain persistent cultures of diatoms, which we possessed at the time. The following diatoms were in this way introduced :—Chaetoceras constrictum, Biddulphia mobiliensis, Skeletonema costatum, Coscinodiscus excentricus, Streptotheca thamensis. The flagellate (Chilomoias sp.) was also intro- duced, since it was present in the culture of Coscinodiscus, The experi- ment was started on August 26th, 1907. On September 6th (11 days) Biddulphia, Coscinodiseus and Chaetoceras were increasing rapidly and were very healthy. Skeletonema was not so good, and no Streptotheca was found. On October 2nd (37 days) Biddulphia was numerous and healthy, Coscinodiscus was healthy but not so numerous. Sheletoneiia was poor, and Chaetoceras was not seen. Flagellates (Chilomonas) had become very numerous. On October 31st (66 days) all the diatoms were in very poor condition, Cosc/nodiscus being slightly better than the others. The flagellates (Chilomonas) were extremely thick, giving the water a deep red colour. Subsequently a small green alga (Plewrococcus mucosus) appeared, having probably been derived from the Coseinodiscus culture. This increased very greatly in quantity, whilst the flagellates became inconspicuous. On July 28th, 1909 (1 year 11 months), some Coseinodiscus, which were still in a healthy condition, were seen in a sample examined from the flask. A great quantity of Plewrococcus, in a healthy condition, was also present, but no other organisms were noted. On this date a subculture was made from the fiask in normal outside Miquel. The subculture gave a considerable growth of Skeletonena, the cells being, however, of a very abnormal character, and a good many normal and 460 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. healthy Coscinodiscus were found in each sample examined. The whole culture was crowded with Chilomonas in a very active state, which gave the whole contents of the flask a deep red-brown colour. Up to August 24th, the green alga (Pleurococcus) had not become sufficiently abundant to be detected by the naked-eye appearance of the flask, though it could be seen in samples examined with the microscope. In another experiment, a flask of Miquel sea-water was inoculated (May 4th, 1908) from two cultures, one containing the green alga (Pleurococeus mucosus) and the other Thalassiosira decipiens. At first both did well, and on May 20th (16 days) there was a very good crop both of the diatom and the alga. Gradually, however, the alga became predominant, and on October 14th (165 days) only quite empty frustules of TZhalassiosvra could be found, whilst the growth of Plewrococeus was abundant and healthy. The only case where a diatom was observed to flourish in the presence of this green alga was in a culture of Nitzschia, a bottom form. In this case a very abundant growth of the diatom was obtained, but the Plewrococecus did not multiply to any extent, although it could always be found on microscopic examination. Ill. NOTES ON PARTICULAR SPECIES OF DIATOMS, ON THEIR METHODS OF REPRODUCTION, AND ON OTHER ALG OCCURRING IN CULTURES. A list has been already given (p. 425) of those species of diatoms which we have obtained in “ persistent” cultures. Of these, a species belonging to the genus Zhalassiosira has been used for experimental work in the great majority of cases. We are not quite certain as to the identity of the species, but since it most resembles 7. decipiens, Grun., we have called it by that name, although it does not exactly conform to the published descriptions of that form. The most characteristic feature of this particular species is the eccentric mark- ings on the valves, which are also seen on the valves of the diatom Coscinodiscus excentricus, Ehr., and, as is typical of the genus, the frustules are united into chains by a delicate filament. Jdrgensen (50, p. 96) describes the valves as “decidedly convex,’ Gran (49) as “ flat,” and both agree that there are marginal spines and a single asymmetrical spine. Our cultural forms are united together by a filament into chains, some of which are made up of five hundred cells and more, but the distance between each is considerably smaller than that figured by Gran, The valves are quite flat and the marginal spines are often ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 461 present, although this is not always the case. The odd asymmetrical apiculus can nearly always be seen. The eccentric markings have only been observed in a few isolated cases, and are then usually very indis- tinct. In one culture these markings on the valves were very distinct, and were also easily seen on the megafrustules (cf. below) which developed in it, but in none of the several generations of cultures started from this one have we been able to find any traces of marking at all. The genus seems to be in considerable confusion, and it is prob- able that the conflicting descriptions given by different observers are due to variations in what is really one species. Persistent cultures of Coscinodiscus excentricus, Ehr., have also been obtained, and it is interesting to note that this diatom sometimes forms chains, but they are rather exceptional. These chains are never as long as those commonly found with Zhalassiosira, two or four cells only being the rule. The filament joining the valves is also finer and more easily broken. The two species are quite distinct, and cultures of them can be discriminated by a practised eye. Two species of the genus Liddulphia are commonly met with in our cultures, namely Biddulphia mobiliensis (Bail.), Grun., and Bid- dulphia regia, M. Schultze. These two forms are generally regarded as one species, but Ostenfeld (54) has recently shown that they are really distinct. We have obtained persistent cultures of both forms from several different samples of plankton, and the two species are easily recognizable, never merging into one another. When Petri dishes, inoculated from plankton (see p. 425), contain both species, the colonies can be easily distinguished with a small hand lens. The most generally accepted theory of the reproduction of the diatomaceze is briefly that the cells divide by simple fission, but on account of the rigid character of the cell walls each division necessitates a decrease in size of the new valve, since this must always be formed inside the old valve. So the frustules gradually get smaller and smaller as multiplication proceeds, thus necessitating some process by which the original size can be re-established. This takes place by the formation of what are known as auxospores, which ultimately form megafrustules, and these in turn multiply by division until the minimum limit of size has again been reached. There are also several special processes of reproduction, but no occurrence of any of these has been noted in our work (cf. Miquel, 14). The diatoms in our cultures multiply by simple fission, and although there is, in nearly every case, a considerable diminution in size when compared with specimens from the plankton, this diminution soon 462 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. seems to reach a limit, where further decrease does not take place. In chains of Thalassiosira, several hundred cells in length, no difference in size between individuals could be made out. Auxospores are commonly formed with every species, but only in the cultures of Coscinodiscus and Thalassiosira have megafrustules been found, and in these they are very exceptional. These megafrustules seem to divide once or twice and then die or form new auxospores. What exactly is the fate of these auxospores, which are often exceedingly numerous, we have not been able to make out. It seems that cultural conditions are not favourable to this mode of reproduction, and that the auxo- spores do not further the multiplication of the diatom at all. If this were not the case, stages of the formation of auxospores into frustules must have been seen in some at least of the very numerous samples examined. As it is, what has been said to take place is, that the cell contents expand and force apart the valves of the diatom and emerge as a spherical body about three or four times the diameter of the parent cell. The chromatophores and diatomin then collect to one side, form- ing a compact cap against the cell wall. Beyond this point no stages have been found, except in the case of the few cultures where mega- frustules were formed. In these the chromatophores, ete., gradually formed into the shape of the diatom (Coscinodiscus), the silicious coat with plain eccentric markings was easily seen inside the spore, and lastly, the cell wall of the spore burst, leaving the megafrustule free. The megafrustule was measured and found to have a diameter three times that of the parent cell. In the case of the diatom we have very largely used for feeding larvee, ete, namely Nitzschia closterium, forma minutissima, a great number of cultures have been made, all originating from the single drop from which the first persistent culture was obtained. The total amount of growth in all the various cultures has been enormous, and the number of generations must be quite inconceivable. No diminu- tion in size has, however, been appreciable, and no sign of any method of re-establishment of size has been seen, although these cultures have been under constant observation for over two years. This seems to prove that the theory of gradual decrease in size with successive generations cannot be generally applied. The following experiment on the rate of multiplication of Thalas- siosira in normal Miquel sea-water was carried out. A single drop from a fresh and vigorous culture was kept under a microscope as a hanging-drop preparation in a moist chamber. The number of diatoms in this drop was counted from time to time, and the results are given in the following table :— ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 463 Number of Geometric Day. frustules. progression. 11th : 59 63 14th aa 62 e 68 19th : : 85 F : 85 27th 4 : 140 : s 120 34th ; 170 : 160 41st 2 : 190 : 5 220 The curve obtained by plotting the number of diatoms against the number of days approximates the curve of an ordinary geometric progression, where the ratio is two and the periods are equal to sixteen days. To show this the figures read off from the curve at the same intervals as the diatoms are appended in the table. From this it will be seen that, after a start had been made and before exhaustion set in, the numbers obtained agree fairly closely with the assumption that every diatom divided once in a period of sixteen days. Probably in normal cultural conditions the rate of multiplication greatly exceeds this figure on account of better lighting, etc. (ep. Miquel, 12). Besides diatoms, many other organisms appear in these cultures. We are indebted to Prof. G. 8. West for the identification of a form of unicellular alga, which is very common and difficult to avoid when attempting to obtain persistent cultures of the Diatomacee, namely Pleurococcus mucosus (Kutz.), Rabenh. This small green alga, if once introduced into a culture of a plankton diatom, will soon multiply at the expense of the latter with its ultimate extinction. It is very hardy and cultures of it in almost every medium seem to last in- definitely. Multiplication beyond a certain point probably does not occur, but the cells retain their colour and normal shape and will start active reproduction if suitable nutrient material is provided. In cultures inoculated from plankton many other forms of unicellular and filamentous alge thrive. Several species belonging to the classes fthodophycee and Myxophycee commonly oceur, but we have not been able to identify them. The most usual filamentous forms of Chlorophycee are Enteromorpha, Vaucheria, Rhizoclonium, ete. It is interesting to note that it was the unintentional appearance of young plants of Laminaria digitata in some of our Petri dishes that led Mr. Drew (4) to cultivate this alga in Miquel sea-water and so discover its early life history. Cultivations of marine alge by these methods would without doubt yield many new species, and would also provide rich material for the study of their modes of reproduction. Many forms of flagellates live either together with diatoms or alone. Among these is an unidentified species of Chilomonas which we have obtained in persistent culture. It multiplies very rapidly, colouring 464 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. the whole medium a deep red-brown. It flourishes in Miquel sea-water, and its nutrition is evidently autotrophic. In one culture in Miquel sea-water inoculated with plankton a number of Coccospheres de- veloped, probably Coccosphwra atlantica, Ostenf. Other flagellates and ciliated infusoria are very commonly met with, such as Lodo, Huplotes, Huglena, etc., which all seem to depend on the diatoms or other vegetable organisms for their food material. IV. THE REARING OF MARINE LARVAL. In the rearing of pelagic larval forms of marine animals,* the principle which we have followed has been to introduce into pure, sterile sea-water the larve to be reared, together with a pure culture of a suitable food. As far as practicable all other organisms have been excluded from the rearing vessels. It should be added that the food used in all successful experiments has been of a vegetable nature, and has continued to grow actively in the vessels. This is important from the point of view of oxygen supply. Under the above conditions, or rather under the nearest approach to them at which we have been able to arrive, no change of water has been found necessary. Methods.—It will, perhaps, best make the matter plain if we first of all describe the actual procedure which we now follow in the case of such an animal as Hehinus esculentus or EL. acutus. The water to be used is first of all prepared by treating water from the aquarium tanks with powdered animal charcoal, filtering it through a Berkefeld filter (p. 431), and collecting it in sterilized glass vessels. All instruments and pipettes are sterilized by baking in an oven, and a fresh sterile pipette is used for each operation during the progress of the work. Specimens of Hehinus are then opened until a perfectly ripe female has been found, that is to say, one in which the eggs separate quite freely, when a portion of the ovary is shaken in sea-water. Pieces of ovary taken from a little below the exposed surface are then placed in sterile sea-water in a shallow glass dish and shaken with forceps in order to get the eggs well separated, or a number of eggs from the centre of the ovary are drawn up with a pipette and placed in the water. A very small quantity of active sperm from a ripe male is then added, very little being sufficient to fertilize a large number of eggs. Excess of sperm should be avoided owing to its liability to putrefy. After an interval of ten or fifteen minutes the water containing the eggs is filtered through bolting silk of 100 meshes per inch, which just allows single eggs to pass through, whilst keeping * See Bibliography ; especially Grave (26), MacBride (28-30), Doncaster (25), ete. ON THE ARTIFICIAL CULLTURE OF MARINE PLANKTON ORGANISMS. 465 back clusters of eggs or other large material. The filtrate is divided amongst a number of tall narrow beakers containing sterile sea- water, and the beakers, after being covered with a glass plate, are placed where the temperature will be uniform and not rise much above 15° C. In the course of twenty-four hours the healthy larve will swim up to the surface and can be easily seen and removed from vessels of this shape. They are transferred by means of sterile pipettes to jars* of sterile sea-water, about fifty to seventy larvee being put in each jar of 2000 c.c. sea-water. At the same time, a good pipetteful of a pure culture of diatom is added to each jar. The small diatom Nitzschia closterivm, forma minutissima, we have found most useful, as its size is suitable, and it grows well in animal-charcoal tank-water, floating throughout the body of the water, and so being in intimate ad- mixture with the larvee. The jars are placed in a moderate light and at as even a temperature as possible.t No further attention is necessary until the larvee have metamorphosed. The metamorphosis takes place in from six to nine weeks after fertilization. Larvee may be taken out from time to time and examined to see if they are feeding well. If the diatoms do not grow sufficiently rapidly in the jar, more should be added from the culture flasks. We are more often troubled, however, towards the end of an experiment by an excessive abundance of diatoms. In this case the jar may either be put in a darker place or some of the water may be drawn off and replaced by a fresh supply of sterile sea-water. Care should be taken to have a sufficient supply of food at the beginning of the experiment, so that the larve may be able to feed as soon as they are ready for food. The method just described can be modified in various ways without detriment to the result. Sufficient sterilization of the water may be effected by heating to 70° C. for fifteen minutes, after which it should be aerated by violent shaking; “outside” water may be used instead of “tank-water,’ and may be treated with Miquel’s solutions in the ordinary way, to ensure a satisfactory growth of the food-diatom. With regard to the food organisms, we have tried to obtain as large a variety of these in pure culture as possible, and then to make trial of a number of them with each batch of larvee on which we have experimented. If no suitable pure cultures are available, success can sometimes be obtained by adding a few drops of tow-netting, collected with a fine-meshed net (180 meshes per inch), directly to the treated « The vessels we use are ordinary green glass sweet-jars, having a capacity of about 2000 c.c., which are kept covered with the glass stoppers provided with such jars, from which the cork band has been removed, + In hot weather we often stand the jars in one of the tanks of circulating aquarium water, which maintains them at a very uniform temperature. 466 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. sterile water containing the larve. In this case one depends on the chance of a suitable food organism growing in the vessel unaccom- panied by any destructive organism. On several occasions a satis- factory result has been reached by proceeding in this way, and the method is generally worth a trial, seeing that the number of larve obtainable from an ordinary fertilization is very large, and many cufferent experiments are easily made with them. We will now give details of some of the results obtained by making use of the methods deseribed, or of their modifications. Hehinus acutus——The first successful experiment was made with this species. Eggs fertilized on June 13th, 1905, produced healthy larve, 50 to 75 of which were placed, three days later, in a glass jar containing 2000 cc. of outside sea-water, filtered through animal charcoal, to which modified Miquel solutions were added. They were fed on a diatom culture, containing a small species of Chaetoceras, which did not form chains, a small diatom probably belonging to the genus Melosira, a small Naviculoid diatom, two minute flagellates, and a small green organism, probably one of the Pleurococcacee. The vessel stood in a shallow tank, through which a stream of aquarium water was flowing, and the temperature was fairly constant at 15° or 16° C.,, though there is one record of 19° C. at the end of July. The first two young Hehinus were seen on July 25th, 42 days after fertilization, and on August Ist 20 were counted. On August 5th (the 53rd day) a careful search through the jar gave 21 young Hchinus of normal size attached to the glass, 6 minute but fully formed Lehinus, about 23 still] in the Pluteus stage, roughly half of which were well advanced. On August 16th some of the water, which had not been changed since the beginning of the experiment, was replaced by “outside” water. On October 5th (16 weeks after fertilization) 12 Hchinus were still alive. Some pieces of red seaweed were placed in the jar, upon which the Hehinus fixed themselves and fed. Several of these specimens lived for over a year, but sufficient attention was not given to finding suitable food for them after the metamorphosis, so that they did not grow very large. Echinus esculentus.—Three successful experiments have been made with #, esculentus. In the first (eggs fertilized April 5th, 1907) “ out- side” water treated with animal charcoal and filtered through filter- cloth, but not otherwise sterilized, was used. A number of jars of 2000 cc. capacity containing larve were set up, and, to the most of these, various diatom cultures then in our possession were added, none of which, however, gave a satisfactory result. In two jars, on the ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 467 other hand, to which no culture was added, there was considerable growth of diatoms and of a flagellate, wpon which the Plutei fed. The first young Hehinus were recorded in both jars on June 8th (64 days), but may have been present a few days earlier. Eventually from 30 to 40 metamorphosed in one jar and about 12 in the other. The temperature varied from 10°5° C. to 12°5° C. In the second experiment (eggs fertilized June 8th, 1908), made with similar water, the larve were fed on a pure culture of WNitzschia closterium, var., and six had completely metamorphosed on July 26th (48 days after fertilization), two more subsequently coming through, The temperature was generally 15° to 16° or 17° C. In the third experiment (eggs fertilized March 29th, 1909) aquarium tank-water treated with animal charcoal and then filtered through a Berkefeld filter was used. Plutei, fed with a pure culture of a small flagellate (probably Chilomonas sp.) grew satisfactorily, and eight young Echinus were found on June Sth (68 days after fertilization), which had probably metamorphosed some days earlier. Two other jars in which Nitzschia closterium, var., was used as food, were not successful, probably because the growth of diatoms became too thick towards the end of the experiment. ichinus miliaris, In the first experiment with this species animal- charcoal Berkefeld water was used, each jar containing as usual 2000 cc. In one jar the Plutei, from eggs fertilized on August 27th, 1907, were fed on a pure culture of Nitzschia closterium, var.. On October 4th, Le. thirty-eight days after fertilization, one Hchinus had just metamor- phosed. On October 29th about a dozen healthy-looking Achini were climbing about the jar, and many were still in a healthy condition on January 8th, 1908. Temperatures: September, 15° to 19° C., October, 16° dropping to 13° towards end, November, 12° to 11° C., December, 15° to 10° C. To another jar containing larvee from the same batch a few drops of fresh Plankton were added as food. The Plutei in this case fed on flagellates and Nitzschia which grew in the jar, and several metamor- phosed. In a second experiment with eggs fertilized on September 15th, 1907, the larvee were fed with Wetzschia closterium, but although there were a few well-advanced Plutei still living on January 8th, 1908, none com- pleted the metamorphosis. _ Cucumaria saxicola. A female Cucumaria, one of a number ina dish containing “outside” water, laid eggs, which were fertilized, and segmented on May 12th, 1906. A number of these were placed in a 468 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. flask in 800 cc. of “outside” water, which had been sterilized by heating and then treated with animal charcoal and filtered. About 1 cc. of fine plankton, containing diatoms, was added to the flask on May 12th. On May 25th some of the water was poured off and a new supply added. As the amount of food seemed small, some culture of a green alga (Plewrococcus mucosus (Kutz.), Rabenh.) was added, and this con- tinued to grow well in the flask. The larvee continued healthy and formed young Cucumaria, of which many were still alive on July 25th, 1907, i.e. fourteen months after fertilization. Some of the water was changed in this flask on May 30th, 1906, June 18th, 1906, September 15th, 1906, and July 25th, 1907. Although many of these Cucumaria remained quite healthy they did not grow to any great size. Probably the food which was suitable to the larve and early stages, ought to have been changed as the animals grew older. Pomatoceros triqueter. The larvee of Pomatoccros are perhaps the easiest to rear, and give the most certain results of any with which we have experimented. They do well on the minute variety of Nitzschia closteritum, but will feed upon almost any small diatom. Since the adults live in calcareous tubes attached to stones, and the tubes have to be broken open before the eggs can be obtained, it 1s not easy to get the latter free from infection of other organisms. If, therefore, the eggs are fertilized and placed in sterilized animal-charcoal water with only moderate precautions, sufficient growth of diatoms or other organisms will generally take place in the jar to feed the larve and bring them to the adult state. When once fixed to the glass the worms are very hardy and healthy, and a stream of ordinary aquarium water can be run through the jar. They then grow rapidly and attain a size equal to any found on the shore. The following experiment may be given in detail to illustrate the time occupied in development. On August 29th, 1907, eggs of Pomatoceros triqueter were fertilized in animal-charcoal Berkefeld water, and some pure culture of Witzeschia closterium, var., added. The larve fed well, and on October Ist (ie. thirty-three days after fertilization) a great number had fixed on the sides of the jar and made quite normal tubes. A constant stream of the ordinary aquarium water was then allowed to run through the jar, and the worms continued to grow and flourish, reaching a large size, and are still alive and healthy (November, 1909). A similar result was obtained from the same batch of eggs by feeding on a pure culture of a flagellate infusorian. Temperatures during these two experiments were between 15° C. and 19° C. Chaetopterus variopedatus. Four experiments were made with this ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 469 species. The food which gave most promise of success was the diatom Nitzschia closteriwm, var. Larvee from eggs fertilized on July 20th, 1908, fed on this material lived until October 30th, and reached an advanced stage. They did not, however, adopt the adult habit and form tubes. Two larvee were also reared to an advanced stage by using flagellates and, in later stages, the diatom Sheletonema costatwm as food. Sabellaria alveolata. One experiment only was made with this species on eggs fertilized on July 19th, 1908. The eggs were fertilized in “outside” water and the larve subsequently transferred to jars containing animal-charcoal Berkefeld aquarium water. They were fed on a pure culture of Vitzschia closteriwm, var., and kept healthy and active and developed well until nearly the end of October, when, simultan- eously with a sudden drop in the temperature from 15° and 16° C. to 12° and 9° C., they sank to the bottom of the vessel and in about three days were all dead. Temperatures:—During July and August, the temperature kept fairly constant at about 17° C., with a range from 15° to i9° C. During September it was generally about 15° C., and continued at about this level until the fall in the middle of October. Archidoris tuberculata. A good many trials have been made to rear the larvee of nudibranchiate molluscs, but up to the present not much success has been achieved. The best experiment was one made with larvee of Archidoris tuberculata. A number of veligers of this species hatched out on May 8th, 1908, from some spawn, which had just been collected from the shore. Some of these were put in a flask containing 1000 ec. of sterilized animal-charcoal water and about 1 c.c. of fine plankton was added. On May 14th a few veligers were transferred to another flask of sterilized animal-charcoal water and some pure culture of the green alga, Plewrococcus mucosus, was added. Whereas the larvee in the original flask did not live long, those provided with the green alga fed well and developed for some time. A number of them were active and vigorous on July 4th, ie. 51 days after hatching, and several were still swimming at the end of July. On August 15th none could be seen moving, but two of those which lay on the bottom, when examined with the microscope, showed no sign of decomposition. The animal was retracted in the shell, but the tissue looked healthy, and the eye-spots and otoliths could be seen. The growth in the flask seemed to be a quite pure culture of Plewrococcus. Larvee were examined again on September 14th, and appeared much as in August, the tissue still showing no sign of dis- 470 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. integration. The flask was not again examined microscopically until July 25th of the following year (1907). No sign of the larve could then be seen, but the culture of Plewrococcus remained pure and healthy. Subsequent experiments were made with spawn, which was deposited by the females in confinement. Although the spawn hatched and gave apparently healthy larvie, these did not live for more than a few days. Calanus finmarchicus. A single experiment is perhaps worth re- cording, as showing that it ought to be possible to rear this species without great difficulty. On August 8th, 1905, to a flask containing 1000 ce. of outside water (unsterilized) there was added 3. cc. of ~Miquel’s solution B and 4 cc. of a 1°5 per cent solution of anhydrous sodium carbonate. A few Calanus finmarchicus and some decapod Zoeas were put in, together with a quantity of a culture containing mixed diatoms. On September 8th all the Zoeas were dead, but three Calanus were alive, and Nitzschia and a number of bottom diatoms were very plentiful. On September 17th the three large Calanus were alive and vigorous, and a considerable number of Nawplii were seen in the flask. By September 22nd two of the Nawpli had developed into young Calanus. These, however, did not live for more than a week or ten days, and the adults also died. The flask was abandoned on November 13th, the water in it not having been changed since the commencement of the experiment. Echinus hybrid. A successful experiment on crossing #. esculentus and #H. acutus was carried out by Mr. W. De Morgan, who was working at the Plymouth Laboratory. We provided him with treated water and diatom cultures for food, and he followed our methods. We are indebted to him for allowing us to publish these results. Some eggs from a ripe #. esculentus were fertilized by active sperm from Z. acutus in sterilized water on March 29th, 1900. Healthy larvee were obtained and were transferred two days later to tank- water, which had been treated with animal charcoal and filtered through a Berkefeld filter. A culture of Nitzschia closterium, var., was added as food, and the larve developed rapidly, feeding well. Several were completely metamorphosed on May 7th, or thirty-nine days after fertilization. In all thirty young hybrids were obtained, and a number of these are still alive and feeding on red weeds. Sacculina carcini. Mr. Geoffrey Smith has recorded the fact (Quart. Journ. Mier. Sei., LI, 1907, p. 625) that he was able to rear the larve of Saceulina up to the Cypris stage, when they attached themselves to ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 471 their host, Carcinus maenas. These larve were kept in aquarium tank-water treated with animal charcoal and filtered through a Berkefeld filter. In this case the question of food did not arise, as the larve do not feed after hatching. It must be noted, however, that these larvee had previously been reared by Miiller and by Delage. Summary of Method for Rearing Larve. We have found that the best results in rearing marine larve have been attained by taking the following precautions :— 1. The eggs of the female selected must be really ripe, and the spermatozoa of the male active. 2. The smallest quantity of sperm necessary to fertilize the eggs should be used. 5. Sterile sea-water, treated in such a way that diatoms, etc., will grow well in it, should be used. No frequent change of water is then necessary. 4, All dishes, jars, instruments, and pipettes should be carefully sterilized before use. Every possible effort should be made to prevent the introduction into the rearing-jars of any organisms other than the larve to be reared, and organisms on which they feed. The jars should be covered with loosely fitting glass covers. . The eggs after fertilization must be separated from all foreign matter, pieces of ovary, or testis, etc. As soon as the larvee swim up they should be pipetted off into fresh vessels of treated water, so as to leave behind any unsegmented eggs, etc. 6. The food organisms should be small in size, so that the larvee can draw them into the mouth by ciliary currents. The food should distribute itself through the body of the liquid and not settle too readily on the bottom of the vessel. (This is one of the great advantages of the diatom Nitzschia closteriwm, forma minutissima. ) 7. The food should be abundant early, so that the larve may commence feeding as soon as they are able to do so. The food, however, must not be allowed to get excessively thick in the water. It can be kept down by diminishing the light .or by changing some of the water. 8. The temperature should be kept as constant as possible. Within limits, the actual degree of temperature is not so important as the avoidance of rapid change of temperature. 9. A good north light, not exposed to direct sunlight, is most suit- able for the rearing-jars. NEW SERIES.—VOL. VIII. NO. 5. Marcu, 1910. 2K Or 472 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 10. In determining the amount of water to be used in any particular vessel, regard must be had to the amount of water surface exposed to the air, which should be large in proportion to the volume of the water. 11. A change of food is generally required after the metamorphosis 12. 13. 14. 15. 16. 17. 18. 19. 20. of the larve. BIBLIOGRAPHY. ; Cultures. : Beijerinck, M. W.—Das Assimilationsprodukt der Kolensiiure in den Chromato- phoren der Diatomeen. Rec. Trav. Bot. Neerland, 1, 1904, p. 28. . Benecke, W.—Uber farblose Diatomeen der Kieler Féhrde. Pringsh. Jahrb., XxXv, 1900, p. 567. . Breazeale, J. F.—Effect of Certain Solids upon the Growth of Seedlings in Water Cultures. Botanical Gazette, x11, 1906, p. 54. . Drew, G. H.—The Reproduction and early Development of Laminaria digitata and L. saccharina. Annals of Botany, xxtv, 1910, p. 177. . Gill, C. Houghton.—See Van Heurck, H. 21 and 57. . Karsten, G.—Die Formanderungen von Skeletonema costatum, Grun., und ihre Abhangigheit von dusseren Faktoren. Wiss, Meeresunters. Kiel. N.F., III, 1898, p. 5. . Karsten, G.—Ueber farblose Diatomeen. Flora, LxXxx1x, 1901, p. 404. . Lockwood, 8. M.—Raising Diatoms in the Laboratory. Journ. New York Mier. Soc., 1886, p. 153. . Lockwood, S. M.—Aberrant Forms in cultivated Diatoms. Amer. Monthly Micr. Journ., 1893, p. 259. Lockwood, 8S. M.—Forms anomales chez les Diatomées cultivées artificiellement. Le Diatomiste, 11, 1893-96, p.9. Ann. de Micrographie, x, 1898, p. 1. . Miquel, P.—De la Culture artificielle des Diatomées. Le Diatomiste, 1, 1890-93, pp. 78, 93, 121, 149, 165. Le Micrographie Préperature, v, 1897, p- 69. Miquel, P.—Recherches expérimentales sur la physiologie, la morphologie, et la pathologie des Diatomées. Ann. de Micrographie, rv, 1891-92, pp. 278, 321, 408, 529; v, 1893, pp. 437, 521; x, 1898, pp. 49,177, 182. Le Micro, Préperature, x1, 1908, p. 174; x11, 1904, p. 32. Miquel, P.—Du rétablissement de la taille et de la rectification de la forme chez les Diatomées. Le Diatomiste, 11, 1893-96, pp. 61, 88. Miquel, P.—Des Spores des Diatomées. Le Diatomiste, 11, 1893-6, p. 26. Miquel, P.—Du noyau chez les Diatomées. Le Diatomiste, 11, 1893-96, p. 105. Le Micro. Préperature, x11, 1904, p. 167 ; x111, 1905, p. 83. Richter, O.—Reinkulturen von Diatomeen. Ber. deut. bot. Gesell., xxz, 1903, p. 493. Richter, O.—Uber Reinkulturen von Diatomeen und die Notwendigkeit der Kieselsiure fiir Nitzeschia palea (Kiitz). W. Sm. Verh. d. Gesell. dent. Naturf. u. Azzte. Breslau, 11, 1904, p. 249. Richter, O.—Zur physiologie der Diatomeen. S. B. K. Akad. Wiss. Wien, cxv, 1906, p. 935. . Richter, O.—Ueber die Notwendigkeit des Natriums fiir eine farblose Meeres- diatomee. Wiesner-Festschrift. Wien, 1908, p. 167. Senft, E.—Ueber die Agar-Agar Diatomeen, Zeit. d. Allgem. dst. Apotheker- Vereines, 1902, n. 9, figs. 1-9. 36. 37. 42. 43. ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 473 21. Van Heurck, H.—Notice biographique sur C. Houghton Gill. Le Diatomiste, 11, 1893-96, p. 125. 2. Van Heurck, H.—Culture des Diatomées. Zeit. f. angew. Mikrosk., 111, 1897, pp. 195 and 225. Rearing. . Agassiz, A.—Revision of the Echini. Cambridge, Mass., 1872-4. 4. Cowles, R. P. Notes on the Rearing of the larve of Polygordius. Johns Hopkins Univ. Circulars xxu, No. 161, 1903. 5. Doncaster, L.—On rearing the later stages of Echinoid Larvee. Cambridge Phil. Soe., x11, 19038, p. 48. . Grave, C.—A Method of Rearing Marine Larve. Science, N.S. xv, 1902, p. 579. . Lillie, R. S.—The Structure and Development of the Nephr.dia of Avenicola. Mittheil. Zool. Sta. Neapel., xvi, 1904-6, p. 341. . MacBride, E. W.—The Rearing of Larvee of -Echinide. Reports, Brit. Assoc., Dover, 1899, p. 438. . MacBride, E. W.—Notes on the Rearing of Echinoid Larvee, Journ. Mar. Biol. Assoc., N.S. vi, 1900-3, p. 94. . MacBride, E. W.—The Development of Hchinus esculentus, together with some points in the Development of H. miliaris and £. acutus. Phil. Trans. Roy. Soc., B. cxcv, 1903, p. 285. . Theél, H—On the Development of Echinocyamus pusillus. Nova Acta R. Soc. Sci; Upsala, 1892. 2. Zeleny, C.—The Rearing of Serpulid Larvee, with Notes on the Behaviour of the Young Animals. Biol. Bull. Woods Holl., viz, 1905, p. 308. Chemistry. 3. Dittmar, W.—On the Alkalinity of Ocean Water. Rept. Challenger Expdt., 1873-76, Chem. 1, p. 124. London, 1884. . Fox, C. J. J—On the co-efficients of Absorption of the Atmospheric gases in Distilled water and Sea-water. Parti, “Carbonic acid.” Publ. de Cireonstanee. Conseil internat. pour l’expl. de la mer. No. 44, 1909. Copenhagen. 5. van ’t Hoff, J. H—Zur Bildung der ozeanischen Salzablagerungen. Braunsch- weig, 1905. Knudsen, M.—Hydrography. Danish Ingolf-Expedtn., 1, part 2, p. 21, 1899. Copenhagen. Krogh, A.—On the tension of Carbonic Acid in natural waters, and especially in the sea. Meddelelser om Grénland, xxv, 1904, p. 333. Copen- hagen. . Raben, E.—Uber quantitative Bestimmung von Stickstoffverbindungen in Meer- wasser. Wissensch. Meeresunts. Kiel, viii, 1905, pp. 81, 279. . Raben, E.—Quantitative Bestimmung der im Meerwasser gelisten Kiselsiure. Wissensch. Meeresunters. Kiel, vi11, 1905, p. 99, 286. . Ringer, W. E—Die Alkalinitaet des Meereswassers. Verh. uit. Rijksinstituut v.h. onderzoek d. zee, 1v, 1909. Helder. . Ringer, W. E., and Klingen, F. I. M. P.—Uber die Bestimmung von Stickstoff- verbindungen im Meereswasser. Verh. uit Rijkinstituut v.h. onder- zoek d. zee., 1, 1907-8. Helder. Salm, E.—Studie iiber Indikatoren. Zeitsch. f. Phys. Chemie. Lvi1, 1906, p. 471. Tornée, H.—On the Carbonic acid in Sea-water. Norwegian North-Atlantic Expdt. (1876-8), Chem. 11, p. 24. Christiania, 1880. 474 ON THE ARTIFICIAL CULTURE OF MARINE PLANKTON ORGANISMS. 44 General. . Baldwin, H. B., and Whipple, G. C.—Observed relations between Oxygen, Carbonic acid, and Algze growths in Weequahie Lake, Newark, New Jersey. Papers and Repts. Amer. Public Health Assoc., xxxu1, 1906. . Brandt, K.—Beitriige zur Kenntniss der chemischen Zusammensetzung des Planktons. Wissensch. Meeresunters. Kiel, 111, 1898, p. 43. . Brandt, K.—Ueber den Stoffwechsel im Meere. Wissensch. Meeresunters. Kiel, 1v, 1899, p. 215 ; v1, 1902, p. 23. 47. Brandt, K.—Ueber die Bedeutung der Stickstoffverbindungen fiir die produk- tion im Meere. Beihefte z. Bot. Centralblatt., xv1, 1904. 48. Brandt, K.—On the production and conditions of production in the sea. Rap- ports et Proces-Verbaux. Conseil internat. pour l’expl. de la mer, TL. Appdix. D. Copenhagen, 1905. 49, Gran, H. H.—Diatomeen. Nordisches Plankton. Kiel u. Leipzig, 1908. Botanischer Teil, x1x. 50. Jorgensen, E.—The Protist plankton and diatoms in bottom samples. Hydro- graphical and Biological Investigations. Bergen, 1906. 51. Klebahn, H.—Ein Uberblick iiber die neuere Diatomeenlitteratur. Archiv. fur Protistenkunde, 1, 1902, p. 421. 52. Lemmermann-Bremen, E.—Flagellate, Chlorophycee, Coccosphzerales und Silicoflagellatee. Nordisches Plankton, Kiel u. Leipzig, 1908. Botani- scher Teil, xx. 53. Oltmanns, F.— Morphologie und Biologie der Algen (with bibliography). Two vols. Jena, 1905. 54, Ostenfeld, C. H.—On the immigration of Biddulphia sinensis, Grev., and its occurrence in the North Sea during 1903-7, ete. Meddelelser fra Komm. for Havunderségelser. Plankton Series 1, No. 6, Copenhagen, 1908. 55. Pfeffer, W.—The Physiology of Plants (English edition). Three vols. Oxford, 62. 1900. 56. Smith, G. P. Darnell--—On the oxidation of Ammonia in Sea-water. Journ. Mar. Biol. Assoc., N.S. 111, 1893-5, p. 304. . Van Heurck, H.—A Treatise on the Diatomace:e (translated by W. E. Baxter). London, 1896. . Vernon, H. M.—The relations between Marine Animal and Vegetable Life. Mittheil. Zool. Sta. Neapel., x111, 1898-9, p. 341. . Whipple, G. C.—Some experiments on the Growth of Diatoms. Technology Quarterly, 1x, 1896, p. 145. Boston. . Whipple, G. C.—The Microscopy of Drinking Water (and bibliography). New York, 1908. . Whipple, G. C., and Jackson, D. D.—Asterionella, its Biography, its Chemistry, and its effect on water supplies. Journ. N.E. Waterworks Assn., xiv, 1899, p. 1. Whipple, G. C., and Parker, H. N.—On the amount of oxygen and carbonic acid dissolved in natural waters, and the effect of these gases upon the occurrence of microscopic organisms. Trans. Amer. Micr. Soc., xu. 1901-2, p. 103. [ 475 ] On the Species Upogebia stellata and Gebia deltura. By W. De Morgan, F.Z.S. As remarked by Stebbing (4 History of Recent Crustacea, p. 185): “Upogebia, Leach, 1814, was founded to receive another species dis- covered by the industrious Montagu, and described by him in 1805 (1808) as Cancer astacus stellatus. . .. It seems to have escaped the notice of writers subsequent to Leach that the earliest name of this genus was Upogebia, which therefore must be retained in preference to Leach’s own alteration of it into Gebia, or Risso’s Gebios.” Some doubt still appears to exist whether Upogebia stellata (Leach) and Gebia deltura (Leach) are distinct, or merely sexual forms of the same species. Leach gives excellent figures of Gebia stellata (Malac. Podolph. Brit., table xxi, figs. 1-9) and Gebia deltura (figs. 9-10). He regarded them as distinct species, and remarks of Gebia deltura: “This species lives with Gebia stellata, with which it was confounded, until the distinctions were discovered by Mr. J. D. C. Sowerby.” I am unable to find out whether Mr. Sowerby recorded his description. Bell (British Stalk-eyed Crustacea, pp. 223-5) describes Gebia stellata and Gebia deltura under the genus Gebia (Leach), of the Thalassinide, and gives good figures of both. He appears to doubt, however, whether they are distinct species, and of G. deltura writes: ‘This species, if it be indeed distinct, differs from the former, G. ste//ata, in the follow- ing particulars: the whole animal is very much larger, sometimes not less than twice the length, and more than proportionately wider. The carapace is much broader and more spreading at the sides. The legs are more robust ; the arm of the first pair is not more than twice as long as it is broad, the wrist even shorter than broad, the hand thicker, and the fingers more nearly of equal length. The sete of the external antenne are shorter in proportion, being, according to Leach’s figure, not more than half the length of the body. The abdomen is broader, more spread, and much less firm in its texture, the sides being almost membranaceous, and the abdominal false feet larger and more voluminous than in the other species. The different Jamelle of the 476 ON THE SPECIES UPOGEBIA STELLATA AND GEBIA DELTURA. tail differ also in some particulars, the exterior being rather broader than it is long, and the middle one, or terminal segment, of the abdomen nearly quadrate. In all other respects the two species very greatly resemble each other.” In a note Bell remarks: “The term ‘deltoid’ appears to be very much misplaced in describing this part.” If Leach referred to the central lamella of the tail, the term is mis- leading, as that plate is certainly subquadrate in form. But, as pointed out by Stebbing (History of Crustacea, p. 186), Leach was no doubt referring to the minor branch of the Uropods, which may reasonably be described as “ deltoid.” Bell further remarks: “I confess I am very doubtful if it will not prove on further investigation that the two British forms, and perhaps also G. littoralis of Risso, constitute but one species. The form and development cf the abdomen, and the great development of the abdominal false feet in G. deltura, are certainly very much like peculiarities belonging to the female sex, and calculated for the support and protection of the ova.” Norman appears to consider that there is only one species. In his Crustacea of Devon and Coriwall, p. 12, he has :— “ Unogebia stellata (Montagu) = Gebia deltura (Leach).” At the Marine Biological Laboratory, Plymouth, I have had the opportunity of examining a good many specimens of both forms, both alive and in spirit. The two forms are always found together at Salcombe, and a day’s hunting may produce a dozen specimens. Sted/ata is rather more common than deltwra. I have kept several of the ste//ata foym in berry under circulation, and the zozas have hatched out, and one specimen of the de/tura form, in berry, which also hatched. In neither case, however, was I able to rear the larve. There are thus males and females of both forms. The genital opening of both forms is situated in the females on the basipodite of the 3rd thoracic appendage, and is covered by a diaphragm. It is very easy to see. In the males, the opening is on the basipodite of the 5th thoracic segment. Close to it, there is a small tuft of sete. It is not so easy to distinguish as in the female. The females of both forms possess modified copulatory appendages, and may be recognised by them, as they are absent in the males. Among the Thalassinide, Upogebia forms a rare exception to the general rule on this point (vide Calman, in 7’reatise of Zoology, ed. by Ray Lankester, part vii, p. 274). ON THE SPECIES UPOGEBIA STELLATA AND GEBIA DELTURA. 477 In large specimens it is easy to distinguish between deléwra and stellata. The width of the abdominal plates in deltura is very noticeable, and the rostrum is blunter. It is altogether a more massive animal, and the spotted appearance, whence the name stellata, Daa ih caked WY WY yi" y ng tyr Uy Oh Wy ACL a? Pe ee Tn /) VA 8 }) Latte wip TNX i eee | Fic. 1.—Upogebia stellata, showing spine. Cam. luc, x 27. Fic. 2.—Gebia deltura. Cam. luc. x 27. is wanting. In deltura the dactylopod is stouter and blunter, and more nearly equals the process of the propodite in length. On the inner side, where the dactylopod hinges, there are two blunt spines. In sfellata the “fingers” are much slighter, the dactylopod longer and slenderer, and the opposite process smaller, than in deltura. 478 ON THE SPECIES UPOGEBIA STELLATA AND GEBIA DELTURA. The hairs on the rostrum and carapace, and also on the edges of the abdominal plates, are longer and thicker in dedéwra than in stellata, and give it a more shaggy appearance. In small specimens, however, these differences are not so marked. But stellata has one mark which always distinguishes it from deltwra, namely, a small spine on the curved edge of the frontal margin of the carapace behind the eye-stalks. In ordinary specimens it is easily seen; in very small ones a lens may be required to detect it, but its presence in sfe/lata is constant. In deltwra it is absent, and the margin of the carapace forms an unbroken curve. The spine is shown in the figure (¢/. Figs. 1 and 2). This spine is not shown in the figures of either Leach or Bell. It would hardly be visible on so small a scale; also, it would hardly be seen in the position in which the animal is drawn. From the above considerations it appears that Upogebia stellata and Gebia deltura are clearly distinct species. [ 479 ] Marine Biological Association of the Ciuited Aingdom. Report of the Council, 1908-9. The Council and Officers. Four ordinary meetings and one special meeting of the Council have been held during the year, at which the average attendance has been ten. The Laboratories at Plymouth and Lowestoft have both been visited by Committees of the Council. The thanks of the Council are due to the Councils of the Royal Society and of the Linnean Society for the use of their rooms for the meetings. The Council have been requested by H.M. Government to continue the work which they have been doing in connection with the Inter- national Fishery Investigations for a further year. The Laboratories. No large repairs have been necessary to the buildings and machinery at Plymouth. The new centrifugal pump has continued to give satisfactory results, and the self-sown invertebrate fauna in the tanks of the aquarium has been larger than usual. At Lowestoft, arrange- ments have been made with the landlord of the house occupied by the Association to continue the tenancy for a further year. The Boats. The steam-trawler Huzley has carried out the international work in the North Sea and English Channel. She was laid up at Plymouth for three months during the winter. The Oithona has worked at Plymouth during the summer months, the collecting in the winter being done, as in previous years, by the sailing-boat Anton Dohrn. The Staff. Mr. R. A. Todd and Dr. W. Wallace have been promoted to the rank of Naturalist, whilst Mr. G. T. Atkinson and Mr. H. J. B. 480 REPORT OF THE COUNCIL. Wollaston have been appointed Assistant Naturalists. The staff is now composed as follows :— Director—E. J. ALLEN, D.Sc. PiymMoutH Laporatory. Assistant Director—L. R. CRAWSHAY, M.A. Hydrographer (International Investigations)—D. J. MatrHews. Assistant Naturalists—A, E. HEFForRD, B.Sc., E. W. NELson. Assistant Naturalist (International Investigations)—A. J. MASON-JONES, M.SC. Lowestorr Lasoratory (International Investigations). Assistant Director —J. O. BoruLky, M.A. Naturalists—-_W. WALLACE, D.SC. R. A. Topp, B.sc. Statistical Assistant—Miss R. M. LEg, M.A. Assistant Naturalists—G. T. ATKINSON. H. J. Buchanan WO.LASTON. Occupation of Tables. The following Naturalists have occupied tables at the Plymouth Laboratory during the year :— Miss BainpripGeE, London (Fish Parasites). Miss Bamrorp, Cambridge (General Zoology). F. J. Bripeman, London (Sponges). A. F. Coventry, Oxford (Cell Lineage). W, C. De Morean, Plymouth (Crustacea and Echinoderms), E. R. Downine, pH.d., Marquette, Michigan (Arenicola). G. H. Drew, Plymouth (Pathology of Fishes). Sir CHARLES ELio7, K.c.M.G., Sheffield (Nudibranchs). T. J. Evans, m.a., Sheffield (General Zoology). F. W.GAMBLE, F.R.S., Manchester (Colour Physiology of Crustacea and Fishes). T. GoopEY, B.Sc., Birmingham (Aurelia). F. H. Grave y, m.sc., Manchester (Polychete Larve). G. H. GROSVENOR, M.A., Oxford (Actinia). Miss A. IsGRove, M.sc., Manchester (Mollusca), J. W. JENKINSON, M.A., Oxford (Embryology). W. O. R. Kine, Cambridge (Polycheetes). C. H. Martin, B.A., Glasgow (Protozoa). J. PEARSON, D.Sc., Liverpool (Cancer). F. A. Ports, B.A., Cambridge (Maldanidae). C. SHEARER, M.A., Cambridge (Histriobdella). Rey. J. H. Scares, London (General Zoology). Rey. G. Wappinerton, London (General Zoology). R. WHITEHOUSE, B.SC., Birmingham (Fishes). H. J. B. Wouaston, Lowestoft (Fishes). W. WoopianpD, D.sc., London (Gobius). In addition to the above, twenty-four students attended the Labora- tory during the Easter vacation, when Mr. G. H. Grosvenor conducted the usual course of instruction in Marine Biology. 5 REPORT OF THE COUNCIL. 481 The Library. The thanks of the Association are due for the following books and current numbers of periodicals presented to the Library during the past year :-— Académie Imp. des Sciences de St. Pétersbourg. Bulletin. American Museum of Natural History. Bulletin. Report. American Microscopical Society. Transactions. ' American Philosophical Society. Proceedings. Armstrong College. Calendar. Australian Museum. Records. Report. Bergens Museum. Aarbog. An Account of the Crustacea of Norway, etc. ; by G. O. Sars. Bernice Pauahi Bishop Museum, Honolulu. Occasional Papers. —— Fauna Hawaiiensis. Memoirs. Board of Agriculture and Fisheries. Annual Report of Proceedings under the Salmon and Freshwater Fisheries Acts. — Annual Report of Proceedings under Acts relating to Sea Fisheries. Report of Proceedings of Annual Meeting. Return of the Number of Steam Trawlers Registered at Ports in the States of Western Europe in 1907. —— Report on the Research Work of the Board in relation to the Plaice Fisheries of the North Sea. Boston Society of Natural History. Proceedings. Bristol Naturalists Society, Proceedings. British Association for the Advancement of Science. Report. British Museum, National Antarctic Expedition, 1901-4. Natural History. Guide to the Gallery of Fishes in the Department of Zoology. Brooklyn Institute of Arts and Sciences. Cold Spring Harbor Monographs. —— Science Bulletin. Bryn Mawr College. Monographs, Reprint Series. Bulletin Scientifique de la France et de Ja Belgique. Cairo Zoological Gardens. Report. —— Special Report. California Academy of Sciences. Proceedings. College of Science, Tokyo. Journai. College voor de Zeevisscherijen. Verslag van den Staat der Nederlandsche Zeevisscherijen. ; Colombo Museum. Spolia Zeylanica. Conchological Society of Great Britain and Ireland. Journal of Conchology. Conseil perm. internat. pour Exploration de la Mer. Bulletin Trimestriel des Résultats acquis pendant les Croisitres Périodiques. —— Bulletin Statistique. — — Publications de Circonstance. ——- Rapports et Procés-Verbaux des Réunions. Cuerpo de Ingenieros de Minas del Peru. Boletin. Danish Biological Station. Report to the Board of Agriculture. 482 REPORT OF THE COUNCIL. Kgl. Danske Videnskabernes Selskab, Oversigt. —— Skrifter. Dept. of Agriculture, ete., Ireland. Reports. —— Scientific Investigations. —— The Department’s Fishery Cruiser Helga. Dept. of Commerce and Labor, U.S.A. Pamphlets. —— Report of the Commissioner of Fisheries. Dept. of Fisheries, New South Wales. Annual Report. —— Edible Fishes of New South Wales. By D. G. Stead. —— New Fishes from New South Wales. By D. G. Stead. —— The Beaked Salmon (Gonorhynchus gonorhynchus, Linnaeus). By D. G. Stead. Dept. of Marine and Fisheries, Canada. Annual Report. —— Supplement to the 32nd Annual Report. —— Georgian Bay Fisheries Commission, 1905-8. Report and Recommenda- tions. —— Dominion British Columbia Fisheries Commission, 1905-7. Report and Recommendations. Deutsche Zoologische Gesellschaft. Verhandlungen. Deutcher Fischerei Verein. Zeitschrift fiir Fischerei. Deutscher Seefischerei Verein. Mitteilungen. Dominion Museum, New Zealand. Bulletin. Falmouth Observatory. Meteorological and Magnetic Reports. La Feuille des Jeunes Naturalistes. Field Museum of Natural History. Annual Report. —— Publications. Finnlandische Hydrographisch-Biologische Untersuchungen, Fisheries Society of Japan. Journal. The Fisherman’s Nautical Almanac ; by O. T. Olsen. Fishery Board of Scotland. Annual Report. Fiskeri-Beretning, 1907-8. Government Museum, Madras, Report. Illinois State Laboratory of Natural History. Bulletin. Imperial University, Tokyo. Calendar. Indian Museum. Illustrations of the Zoology of R.I.M.S. Ship Investigator. Institut de Zoologie, Montpellier. Travaux. Internationale Meeresforschung. Jahresbericht. R. Irish Academy. Proceedings. Kansas University. Science Bulletin. Kommission zur wissenschaftlichen Untersuchung der Deutschen Meere, ete. Wissenschaftliche Meeresuntersuchungen. Kommissionen for Havunderségelser, Copenhagen. Meddelelser, series Fiskeri, Hydrografi, Plankton. Skrifter. Kgl. Norske Videnskabernes Selskab. Skrifter. Laboratoire Biologique de St. Pétersbourg. Bulletin. Lancashire Sea Fisheries Laboratory. Report. Lancashire and Western Sea Fisheries. Superintendent’s Report. Leland Stanford Junior University. Publications. Linnean Society, N. 8S. Wales. Proceedings. Liverpool Biological Society. Proceedings and Transactions, REPORT OF THE COUNCIL. 483 Liverpool Marine Biology Committee. Marine Biological Station at Port Erin. Report. Manchester Microscopical Society. Annual Report and Transactions. Marine Biological Association of the West of Scotland. Report. Marine Biological Laboratory, Woods Holl. Biological Bulletin. Mededeelingen over Visscherij. Meteorological Office. Monthly Pilot Charts, North Atlantic and Mediterranean, —— Monthly Pilot Chaits, Indian Ocean and Red Sea. —— Annual Report of the Committee. R. Microscopical Society. Journal. Ministére de l’Instruction Publique, France. Nouvelles Archives des Missions Scientifiques. Ministére de la Marine, France. Travaux du Service Scientific des Péches Maritimes en 1906. Musée Oceanographique de Monaco, Bulletin. Museo de La Plata. Anales. —— Revista. Museo Nacional, Buenos Aires. Anales. Museum of Comparative Zoology, Harvard College. Bulletin. —— Memoirs. ——— Report. Muséum National d’Histoire Naturelle, Paris. Bulletin. ——- Nouvelles Archives. The Museums Journal. Naturforschende Gessellschaft in Basel. Verhandlungen. Naturhistorischen Museum, Hamburg. Mitteilungen. Neapel. Mitteilungen aus der Zoologischen Station. Nederlandsche Dierkundige Vereeniging. Verslag. —— Tijdschrift. New York Academy of Sciences. Annals. New York Zoological Society. Bulletin. —-— Report. New Zealand Institute. Transactions and Proceedings. Nikolsk : ?Etablissement de Pisciculture. Iz Nikol ‘skagho R‘ibovoduagho Zavoda. Norges Fiskeristyrelse. Aarsberetning vedkommende Norges Fiskerier. Northumberland Sea Fisheries Committee. Report on Scientific Investigations. La Nuova Notarisia. Oberlin College. The Wilson Bulletin. Otago Acclimatisation Society. Report. Work of Acclimatisation ; by R. Chisholm. Owens College, Manchester. On anew Phytophagous Mite, Lohmannia insignis, Berl. var. dissimilis n. var., with notes on other species of economic im- portance ; by C. G. Hewitt. —— The Physical Basis of Hereditary Characters ; by 8. J. Hickson. —— On the systematic position of Ewnephthya maldivensis, Hickson ; by 8. J. Hickson, — The Percy Sladen Trust Expedition to the Indian Ocean in 1905, XIX. The Stylasterina of the Indian Ocean; by 8. J. Hickson and H. M. England. — On the Structure of Dendrosoma radians ; by 8. J. Hickson and J. T. Wadsworth. 484 REPORT OF THE COUNCIL. Oxford University Museum, Catalogue of Books added to the Radcliffe Library. Physiographiske Forening. Christiania. Nyt Magazin for Naturvidenskaberne. Plymouth Museum and Art Gallery. Annual Report. Quarterly Journal of Microscopical Science. (Presented by Sir E. Ray Lankester, K.C.B., F.R.S.) Queensland Museum. Annals. Rijksinstituut voor het Onderzoek der Zee. Helder. . Jaarboek. Verhandelingen. —— Vangstatistieken van Hollandsche Stoomtrawlers. Royal Society of Edinburgh. Proceedings. — — Transactions. Royal Society of London. Philosophical Transactions. —— Proceedings. —— National Antarctic Expedition, 1901-04, Physical Observations. Meteor- ology. Album of Photographs and Sketches. Reports of the Evolution Committee. —— Year-Book. Royal Society of Victoria. Proceedings. Selskabet for de Norske Fiskeriers Fremme. Norsk Fiskeritidende. Senckenbergische naturforschende Gesellschaft, Frankfurt. Bericht. Smithsonian Institution. A Further Report on the Ostracoda of the U.S. National Museum ; by R. W. Sharpe. —— North American Parasitic Copepods: A List of those found upon the Fishes of the Pacific Coast, with descriptions of new genera and species ; by C. B, Wilson. —— The Isopod Crustacean, Ancinus depressus (Say.) ; by H. Richardson. —— Comatilia, a Remarkable New Genus of Unstalked Crinoids ; by A. H. Clark. —— Four New Species of Isopods from the Coast of California; by S. J. Holmes and M. E. Gay. —_—- Some New Isopods of the Family Gnathiidae from the Atlantic Coast of North America ; by H. Richardson. —— The Amphipoda collected by the U.S. Bureau of Fisheries’ Steamer Albatross off the West Coast of North America, in 1903 and 1904, with descriptions of a new family and several new genera and species ; by 8. J. Holmes. —— The American Species of Snapping Shrimps of the Genus Synalpheus ; by H. Coutiere. —— Alcyonaria of the Californian Coast ; by C. C. Nutting. Sociedad Scientifica de Sao Paulo. Revista. Société Belge de Géologie, etc. Bulletin. —— Nouvelle Mémoires. Société Centrale d’Aquiculture et de Péche. Bulletin. Société d’Océanographie du Golfe de Gascogne. Rapports. Société Suisse de Péche et Pisciculture. Bulletin. Société Imp. Russe de Pisciculture et de Péeche. Vyestnik R‘ibopom‘shleunosti. Société Zoologique de France. Bulletin. ; —— Mémoires. South African Central Locust Bureau. Report. South African Museum. Annals. -—_— Report. ? REPORT OF THE COUNCIL. 485 Station de Pisciculture et d’Hydrobiologie, Toulouse. Bulletin Populaire. Station de Recherches Maritimes, Ostende. Travaux. Svenska Hydrografisk Biologiska Kommissionens. Skrifter. Kgl. Svenska Vetenskaps-Akademien, Arkiv for Botanik. —— Arkiv for Zoologie. Transvaal Museum, Annals. —— Report. Unione Zoologica Italiana. Rendiconto. United States Bureau of Fisheries. Bulletin. United States National Herbarium. Contributions. United States Natural Museum. Bulletin. —— Proceedings. R. Universita di Napoli, Museo Zoologico, Annuario. —— Centenario della Cattedra di Zoologia nella R. Universita di Napoli, 1806-1906. University of California. Publications. Zoology, Physiology, Botany. University of Pennsylvania. University Bulletins. ——-~ Catalogue. —— Contributions from the Botanical Laboratory. —— Proceedings of “ University Day.” —— Provost’s Report. University of Toronto. Studies. Kgl. Vetenskaps Societeten, Upsala. Nova Acta. Visschershaven, Ijmuiden. Jaarsverslag. Zoological Society of Japan. Annotationes Zoologice Japonenses. Zoological Society of London. Proceedings. —— Transactions. Zoological Museum, Copenhagen. The Danish Ingolf-Expedition. Zoologischen Museum, Berlin. Bericht. —— Mitteilungen. Anon. Bericht iiber die von Herrn Dr, Déderlein in Japan gesammelten Pycnogoniden ; by A. Ortmann. —— Uebersicht der von P. Schmidt und W. Braschnikow in den Ostasiatischen Ufergewissern gesammelten Pantopoden ; by W. Schimkewitsch. —— Zur Pantopoden-fauna des Sibirischen Eismeeres, Mr. E. T. Browne. Uber die Nesselkapseln von Hydra ; by H. Grenacher, —— Zur Frage tiber die Keimblatterbildung bei den Hydromedusen ; by W. Gerd. —— Uber die Entwicklung der Aurelia aurita und der Colylorhiza borbonica ; by A. Goette. —— Note on Selaginopsis (= Polycerias Hincksiz, Mereschkowsky), and on the Circumpolar Distribution of certain Hydrozvoa ; by A. M. Norman. —— Om Forngelsen af Ernaeringsindividerne hos Hydroiderne ; by G. M. R. Levinsen. —~~ Uber eine neue Form des Generations-wechsels bei den Medusen und iiber die Verwandtschaft der Geryoniden und Aeginiden ; by E. Haeckel. —— Preliminary Report of the Biological Results of a Cruise in H.M.S. Valorous to Davis Strait in 1875 ; by J. Gwyn Jeffreys. 486 REPORT OF THE COUNCIL. Mr. E. T. Browne, Report on the Physical Investigations carried on by P. Herbert Carpenter in H.M.S. Valorows during her return voyage from Disco Island in August, 1875 ; by W. B. Carpenter. —— Review on “Das System der Medusen” von Dr. Ernst Haeckel; by A. Agassiz. —— Ueber Tastapparate bei Hucharis multicornis ; by Th. Eimer. —— Histoire Naturelle des Polypes composés d’Eau douce ; by Dumortier and Van Beneden. —— Poriferen, Anthozoen, Ctenophoren und Wiirmer von Jan Mayen ; by E. von Marenzeller. —— Auszug aus den Beobachtungen tiber die Siphonophoren von Neapel und Messina angestellt im Winter 1859-60 ; by W. Keferstein and E. Ehlers. ——. De Zoophytorum et historia et dignitate systematica ; by R. Leuckart. Dr. G. H. Fowler. Biscayan Plankton collected during a cruise of H.M.S. Research in 1900. VIII-X. Dr. H. R. Mill. Symons’s Meteorological Magazine. Mr. E. W. Nelson. Microscopy; by E. J. Spitta. Dr. A. E. Shipley. On the Fauna of the Bradford Coke Bed Effluent ; by Dr. A. Meixner. To the authors of the Memoirs mentioned below the thanks of the Association are due for separate copies of their works presented to the Library :— Ameghino, F. Le Litige des Scories et des Terres Cuites Anthropiques des Formations néogenes de la République Argentine. Bainbridge, M. E. Notes on some Parasitic Copepoda; with a description of a new species of Chondracanthus. Church, A. H. The Polymorphy of Cutleria multifida (Grev.). Cligny, A. Sur un nouveau genre de Zeidés. Deux Clupeides a supprimer de la Nomenclature Harengula latulus, C. et V., et Meletta phalerica (Risso). Cole, G. W. Bermuda in Periodical Literature. Cooper, W. F., and Robinson, L. E. On six new species of Ixodidae, including a second species of the new Genus Rhipicentor, N. and W. Cotton, A. D. Leathesia crispa, Harv. Dakin, W. J. The Osmotic Concentration of the Blood of Fishes taken from Sea-water of Naturally Varying Concentration. —_— Methods of Plankton Research. —— Notes on the Alimentary Canal and food of the Copepoda. Darbishire, A. D. On the Result of Crossing Round with Wrinkled Peas, with Especial Reference to their Starch-grains. —— An Experimental Estimation of the Theory of Ancestral Contributions in Heredity. —— Some Tables for illustrating Statistical Correlation. Davenport, C. B. Determination of Dominance in Mendelian Inheritance, —— Heredity and Mendel’s Law. —— Inheritance in Canaries. —— Co-operation in Science. Davenport, G. C., and Davenport, C. B. Heredity of Eye-colour in Man. —— Heredity of Hair-form in Man. . REPORT OF THE COUNCIL. 487 Dorée, C. The Occurrence and Distribution of Cholesterol and allied bodies in the Animal Kingdom. Driesch, Hans, Zwei Mitteilungen zur Restitution der Tubularia. —— Zur Theorie der Organischen Symmetrie. —— Uber eine fundamentale Klasse morphogenetischer Regulationen. Eliot, C. On the Genus Cumanotus. —— Reports on the Marine Biology of the Soudanese Red Sea, XI. Notes on a Collection of Nudibranchs from the Red Sea. Elmhirst, R. Notes on Nudibranchiate Molluscs. Foster, E. Notes on the Free-swimming Copepods of the waters in the vicinity of the Gulf Biologie Station, Louisiana. Goodey, T. On the presence of Gonadial Grooves in a Medusa, Aurelia aurita. Gough, L. H. Notes on South African Parasites. Harmer, S. F. Address to the Zoological Section. [British Association. ] Harrison, R. G. Regeneration of Peripheral Nerves. Herdman, W. A. Address delivered at the Anniversary Meeting of the Linnean Society, May 24th, 1908. Hjort, J. Review of Norwegian Fishery and Marine Investigations. Hoffbauer, C. Weitere Beitrage zur Alters-und Wachstumsbestimmung der Fische, spez. des Karpfens. Horst, R. On the Supposed Identity of Nereis (Neanthes) succinea, Leuck., and N. perrieri, St. Jos. —— On a Bhawania specimen. A Contribution to our Knowledge of the Chrysopetalide. Janet, C. Histolyse, sans phagocytose, des muscles vibrateurs du vol, chez les reines des Fourmis. —— Histogénese du tissu adipeux remplagant les muscles vibrateurs histolysés apres le vol nuptial, chez les reines des Fourmis. —— Histolyse des muscles de mise en place des ailes, apres le vol nuptial, chez les reines de Fourmis. —— Anatomie du corselet et histolyse des muscles vibrateurs, aprés le vol nuptial, chez la reine de la Fourmi (Lasius niger). M‘Intosh, W. C. Notes from the Gatty Marine Laboratory. Man, J. G. de. Description of a new species of the genus Sesarma, Say., from the Andaman Islands. —— On Caridina nilotica (Roux) and its varieties, —— Decapod Crustacea, with an Account of a small collection from Brackish Water near Calcutta and in the Dacca District, Eastern Bengal. Martin, C. H. Notes on some Oligochaets found on the Scottish Loch Survey. —— Notes on some Turbellaria from Scottish Lochs. —— The Nematocysts of Turbellaria. —— Weldonia parayguensis, a doubtful form from the fresh water of Paraguay. Montgomery, T. H. On the Morphology of the Excretory Organs of Metazoa ; A Critical Review. Moore, J. P. Descriptions of New Species of Spioniform Annelids. —— Description of a New Species of Annelid from Woods Hole. —— Some Polychaetous Annelids of the Northern Pacific Coast of North America. Norman, A. M. The Podosomata (= Pyecnogonida) of the Temperate Atlantic and Arctic Oceans. Nuttall, G. H. F., Cooper, W. F., and Robinson, L. E. On the Structure of “ Hallers Organ” in the Ixodoidea. —— On the Structure of the Spiracles of a Tick—‘‘ Haemaphysalis punctata,” Canestrini and Fanzago. NEW SERIES.—VOL. VIII. No. 5. Marcu, 1910. PAST 488 REPORT OF THE COUNCIL. Pfeffer, G. Teuthologische Bemerkungen. Prince, E. E. Presidental Address [Royal Society of Canada], The Biological Investigation of Canadian Waters, with Special Reference to the Govern- ment Biological Stations. Pitter, A. Die Ernahrung der Fische. Sauvageau, C. Le Professeur David Carazzi de VUniversité de Padoue (Italie), les Huitres de Marennes et la Diatomée Bleue. Schaeberle, J. M. On the Origin and Age of the Sedimentary Rocks. Sedgwick, A. A Student’s Text-Book of Zoology. Vol. III. Shipley, A. E. Interim Report on the Parasites of Grouse. Note on Cystidicola farionis, Fischer. A Threadworm parasitic in the swim-bladder of a Trout. —— Note on the Occurrence of Triaenophorus nodulosus, Rud., in the Norfolk Broads. —— A Cause of Appendicitis and other Intestinal Lesions in Man and other Vertebrates. Sumner, F. B. The Biological Laboratory of the Bureau of Fisheries at Woods Hole, Mass. Report of Work for the Season of 1907. Tattersall, W. M. Two new Mysidae from Brackish Water in the Ganges Delta. Trybom, F. Die im Jahre 1906 ausgefiihrten schwedischen Untersuchungen mit markierten Plattfischen in der Ostsee. ——Nachtrag zum Bericht tiber die mit Schollen und Hummern an der Westkiiste Schwedens ausgefiihrten Markierungen. Vincent, S., and Thompson, F. D. The Islets of Langerhans and the Zymo- genous Tubules in the Vertebrate Pancreas, with special reference to ae Panereas of the Lower Vertebrates. Walker, A. O. Amphipoda Gammaridea from the Indian Ocean, British East Africa, and the Red Sea. Woodruff, L. L. Effects of Alcohol on the Life Cycle of Infusoria. —— The Life Cycle of Paramecium when subjected to a Varied Environment. General Work at the Plymouth Laboratory. A report by Mr. L. R. Crawshay has been published in the Journal of the Association (Vol. VIII, Pt. 3) on an experiment in the keeping of Salmon in sea-water at the Plymouth Laboratory, which was carried out for the Duke of Bedford. Salmon smolts, which were two years old when first transferred to sea-water in February, 1906, showed signs of maturity in November of the same year. They were then transferred to fresh water, and produced fertile ova. In March, 1907, the fish were returned to sea-water, and they were again returned to fresh water, and spawned in the autumn of that year. The smolts in the above experiment had been reared artificially in the hatchery at Endsleigh. A similar experiment is now being carried on with wild smolts. Two reports on the Western Mackerel Fishery have been published REPORT OF THE COUNCIL. 489 in the Journal. One, by Mr. G. E. Bullen, deals with the food of the mackerel, and suggests a correlation between the abundance of mackerel on the fishing grounds off the Cornish coast in May, and the amount of Copepod plankton, upon which the fish feed, present in the water at the time. The second paper, by Dr. Allen, attempts to carry the question a step further, and shows some evidence for thinking that the abundance of mackerel in May varies with the amount of sunshine in the earlier months of the year (February and March). It is suggested that the amount of sunshine influences the growth of diatoms and other plant life, which in its turn influences the Copepod plankton upon which the mackerel feed. Mr. E. W. Nelson has again been engaged, in association with Dr. Allen, in experiments on the cultivation of marine plankton diatoms and the rearing of pelagic larve. A report on this work is now in preparation. Mr. A. E. Hefford has been occupied in studying the reproduction of teleostean fishes in the neighbourhood of Plymouth by means of obser- vations of the gonads of mature fishes, and of the eggs and larve taken in tow-nettings, and in a modified form of the Petersen young- fish trawl. Records have been kept of the pelagic eggs collected at regular intervals during the early months of the present year. The eggs, with few exceptions, were kept alive in the Laboratory, and observations were made on the developing embryos and the early larval stages. An outstanding feature of the investigation is the preponderance in abundance, though not in number of species, of the eggs of unmarket- able fishes over those of marketable forms, those of JJotella and of Callionymus lyra being particularly abundant and of continuous occurrence. The commencement of spawning for most of the species observed appears to have been earlier this year than usual. The International Fishery Investigations. The following is a summary of the work done, and of the conclusions arrived at by the scientific staff working under the direction of the Council. Section I-NORTH SEA WORK. A. WORK OF THE SS. “HUXLEY.” From June Ist, 1908, to the end of May, 1909, the Hualey made nine voyages, in the course of which 193 hauls of the commercial trawl were made, together with 116 hauls of various smaller nets and gear. The total number of voyages made by the Huzley from the commence- 490 REPORT OF THE COUNCIL. ment of the investigations to the present time is 108; the totat number of hauls made with commercial trawls is 1447, that with smaller gear, 1269. TRAWLING INVESTIGATIONS.—The investigation of fixed stations and fixed lines, which was carried out in the spring of 1908, was repeated in June and August of that year, the gear used being the same as on the first occasion. Trawling also took place along the East Anglian coast, and in The Wash, for the collection of soles; and on the Dutch, Danish, and English coasts, in order to obtain plaice for Vitality Experiments and for Transplantation. The Association is indebted to the Eastern Sea Fisheries District Committee, and to Mr. H Donnison, their Inspector, for assistance rendered by the Protector in connection with the first of these operations. The Huxley also obtained eight boxes of plaice from Teignmouth Bay, for the purpose of otolith investigation. DREDGING INVESTIGATIONS.— Various descriptions of small gear were used both at the fixed stations and elsewhere. During the year 39 samples of the sea bottom were added to the collection already made. FisH MEAsuRED.—Over 107,000 fish were measured at sea during the year. As in past years, the entire catch was measured on nearly all occasions. The details as to the number of plaice, haddock, and other species dealt with are as follows :— YEAR. PLAICE. HaAppbock. OTHERS. TorTats. 1903-875 8 139,964, -48'513... (295,247 oe) 483 724 100829) 225 77734820 “L105 37153. ee eal Totals 174,785 50,323 366,400 ... 591,508 During the past winter the measurements and maturity examination of plaice have been continued on the smacks and fish-market at Lowestoft. From the end of October, 1908, to the close of March, 1909, over 17,000 plaice from the south part of the North Sea have been dealt with. MARKING EXPERIMENTS.—From the commencement of the investiga- tions 15,887 plaice, together with 713 soles and 552 other fish, have now been marked and liberated by the Association. Of these, 3515 plaice, 51 soles, and 110 other fish have been recovered. During the year 1908-9, 1385 marked plaice were liberated ap- proximately at the position at which they were captured. The majority of these were marked in the southern extremity of the North Sea, in March, with a view to casting further light on the movements * Excluding certain small fish caught in small gear in 1907. REPORT OF THE COUNCIL. 491 of the large spent fish which are then leaving this portion of the sea. It is intended to conduct similar experiments in January, 1910, as the plaice whose movements it is desired to study can usually be obtained in greater numbers earlier in the year. Over three thousand fish also were taken in the North Sea and transplanted to other grounds. Of these, 2550 were transplanted to the Dogger Bank, having been procured in about equal numbers on the English, Dutch, and Danish coasts. Plaice taken to the Dogger Bank from the Dutch and Danish coasts in May, 1908, were found, on recapture in December last, to have differed somewhat in their rate of growth. It was accordingly considered advisable to secure comparable data as to the growth rate, on the Dogger Bank, of plaice brought from different localities. During the year 473 plaice were taken to the Devon bays. Twenty-three plaice were brought from the Barents Sea by a member of the staff on the steam trawler Princess Lowise, and notwithstanding the great change in temperature experienced on the voyage, were liberated in apparently good condition in the North Sea. Twelve of these fish have been recovered, and were found to have grown at a rapid rate. The following table gives the particulars as to the numbers of plaice recaptured during the year, with the exception of these twelve fish. Recovered from Ordinary Recovered after Trans- Marking plantation to Year of Liberation. Experiments, Dogger Bank. Devon Bays. Prior to June 11,1906 ... me 4 13 sae June 1, 1906, to May 31, 1907 ... 25 96 — eS WN, . 19082) S140 211 ae > 27908 : 1909... 293 49 30 Total ae sit pee 20 369 30 There have thus been recaptured during the year 861 plaice. VITALITY EXPERIMENTS.—The plaice caught in ten hauls of the trawl, 3407 in all, were subjected to experiments designed to deter- mine the length of time it is necessary to keep trawled plaice in circulating sea-water, in order satisfactorily to test their condition. While no period was found in all cases sufficient for such tests, the retention of the fish for twenty hours in the tanks, with periodic removal of dead fish, appears greatly to reduce the errors of experi- ment. A discussion of these experiments has been added to the report on the previous Vitality Experiments carried out by the Association, which has now been published. 492 REPORT OF THE COUNCIL. B. LABORATORY WORK. AGE AND GROWTH OF PLAicE.—During the last year a report has been issued dealing with the size and age of plaice at maturity in the North Sea and English Channel. A report has been in preparation dealing with observations on the age and size of over 19,500 plaice collected at different seasons and in different years over a wide area of the North Sea and in the western part of the English Channel. The ages of these fishes have been determined by examination of their otoliths or ear-stones. The investigation of this material has enabled the average size of plaice of given age on many different fishing grounds to be determined, and has brought to light some interesting differences. Considerable pains have been taken to determine the true average growth of plaice in the region between the English and Dutch coasts, a task which is complicated by the circumstance that the size of plaice of the same age varies according to the distance from land. This difficulty has been overcome by determining the ages and sizes of all plaice caught in continuous lines of trawlings extending from the Dutch coasts into the open sea. The results of several series of observations along these lines agree very closely. They show, among other things, that the average growth of plaice in this region during the first three years is at the rate of 6-7 cm. a year: plaice of three years old averaging 20-21 om. (about 8 inches) in length. In the western part of the Channel growth of young plaice is more rapid, the average length at three years old being 28 em. (11 inches). Plaice do not arrive on the Dogger Bank in any considerable num- bers until they are about four years old. In the following year, judging from the average size of five-year-old plaice in this region, they grow faster than plaice of the same age in the southern and eastern parts of the North Sea. This observation is in harmony with the results of the transplantation experiments. A somewhat sudden diminution in the average rate of growth takes place at the age at which the majority spawn for the first time. In the western part of the Channel these phenomena occur about two years earlier than in the central part of the North Sea. An investigation of the proportions of the sexes at different ages in collections from the North Sea and English Channel has also brought to light interesting differences, which also appear to be associated with the age at which maturity first occurs in the two sexes in the two regions. A comparison of the number of plaice of different ages caught per REPORT OF THE COUNCIL. 493 hour with the trawl (1) in May and (2) in September at various distances along a line between Texel and the Leman Banks, has shown that the mass of each age group is situated further from the Dutch coast in the latter than in the former month. These observations distinctly indicate an off-shore movement of shoals of successive ages in the course of the summer, as has been shown by the results of marking experiments. These results thus confirm conclusions arrived at by Garstang (Internat. Investigations, Mar. Biol. Assoc. Report I, p. 93) from a study of the trawling investigations carried out by the s.s. Hualey concerning the source of the plaice found on the Leman Banks and Ground, and those of Redeke (Proces Verbaux, III, Ap. H) concerning the distribution of plaice off the Dutch coast. TRAWLING INVESTIGATIONS.—The particulars of the trawling stations of the ss. Huzley in 1904-5, illustrated by charts of the trawling courses, have been published, together with detailed measurements of the plaice caught in these years, and summaries, in 10 cm. groups, of these and other species of fish taken in each haul. An examination of the catch per hour of plaice and dabs taken at the fixed trawling stations during 1908 with the otter and beam trawls, both partially covered by small-meshed net and uncovered, has been made, with a view to gaining information as to the constancy of action of each description of gear, and of the relative powers of capture of the otter and beam trawls. Catches from comparable hauls made in earlier years have also been examined, and the catches from day and night hauls made under similar conditions compared. From this examination it appears that the day and night catches of plaice made by the s.s. Huxley in the North Sea as far north as the Dogger Bank do not differ appreciably. The comparative catching powers of the otter and beam trawls agreed closely with those arrived at by Garstang (Report on the Trawling Investigations, 1902-3, Internat. Investigations, Mar. Biol. Assoc. Report I, 1902-8, p. 74) for the action of these nets in the same region on a similar bottom. EXPERIMENTS WITH SMALL-MESHED NETS COVERING THE COMMERCIAL TRAWLS.—The measurements of fish taken in trawls covered in whole or in part by small-meshed net have been tabulated. Eliminating twenty experiments in which the net was torn, a total of over 112,700 fish, taken in 118 hauls, have been treated. In all these experiments the cod-end was covered, sometimes alone, sometimes with part of the batings, with all the batings, with the batings and square, or with all the trawl except the belly. The 494 REPORT OF THE COUNCIL. following table shows the numbers of fish of various species dealt with :— NUMBER Measured. Computed. Tora.s. Plaice 12,009 o..- — jee e260 Dabs AV ou, tan. sh OOSGO OL eee OOOO Haddock 524070" ax — eae le) Cod TT SOt pis. — pel pielS6 Whiting 14556 ... 6,447 .. 21,003 Totals 96.648 ..- 16,085 ... 112733 From a first examination of the results the following table has been drawn up, showing approximately for the various species the sizes at which 50 per cent of the fish are retained in the cod-end :— OrreR TRAWL. BEAM TRAWL. Plaice — 10°5 em. Dabs 14 em. 12° sem: Haddock 19 cm. = Whiting 19-20 cm. 14°5 em. Cod ca. 20em. ca. 14 em. It will be seen that the beam trawl, which has a smaller mesh than has the otter, retains a larger percentage of the smaller fish. Markina EXpeRIMENTS.—The plaice-marking experiments of the years 1906-8 are under examination. The results of these experiments confirm conclusions drawn from previous experiments made in the Southern Bight and on the Eastern Grounds, and add considerably to the knowledge of the movements of plaice on the Flamborough Off and adjacent grounds. INVERTEBRATE Fauna.—The report on the Invertebrate Fauna is approaching completion. The records have been classified in grounds whose delimitation has been carried out with reference primarily to the texture of the bottom, with, in the case of the larger grounds, subdivisions based on depth or average salinity, or made by arbitrary lines. A study has also been made of the frequency of capture of the various species in the grounds chosen, and of the comparative in- portance of depth and texture in determining distribution in the North Sea. Borrom Dxposirs.—A report on the bottom deposits is approaching completion. It is based on the examination of 568 samples, together with records obtained from material brought up in trawling and dredging. The distribution of various grades of deposit has been REPORT OF THE COUNCIL. 495 studied, and a provisional division of the southern part of the North Sea into grounds on the basis of the textures of the bottom carried out. S0TTOM TRAILER EXPERIMENTS.—The particulars obtained from the cards returned from Mr. Bidder’s Bottom Trailer experiments have been arranged and analysed. Three new series of experiments conducted in 1906 have been examined, and three old series of 1904 and 1905 revised. ‘The direction of the bottom currents and the approximate velocities have been ascertained. The series are mutually confirmatory in their indications. A very large number of the bottles have been recovered, 81 per cent of the cards from the first series having been returned. The percentage returned within twelve months of their being put out is between 50 and 60 per cent. C. FISHERMEN’S RECORDS. A report on the Lowestoft Trawling Records, dealing with plaice and soles, has been completed and published. A report on the catches of plaice, soles, turbot, and brill by the Grimsby trawlers is approaching completion. The monthly average catches in different areas have been calculated and analysed. The report deals with 13,246 hauls, made from 1904 to 1907, during nearly 50,000 hours’ fishing. All these species are found to be relatively very numerous on the Eastern Grounds, off the Danish coasts, and to decrease rapidly from east to west, and all, with the exceytion’ of brill, show fairly regular seasonal variations in several areas. Plaice show an off-shore move- ment from the Eastern Ground in the summer, large plaice appear to migrate southwards in the winter, while small plaice disappear almost entirely from the catches at this time. Soles show a very definite distribution. They are limited to the grounds south of a line drawn from the Horn Reef North Grounds to the neighbourhood of Flamborough Head. North of this line in the region investigated they are very scarce. Turbot and brill have also been examined. The records are now being examined with regard to the catches of cod, haddock, and whiting, and the monthly averages for the period 1904 to 1907 have been calculated for each area. The records have yielded material for determining the relation between various statistical units, and factors connecting the rate of fishing per voyage, per day, per haul, and per hour have been calculated. 496 REPORT OF THE COUNCIL. Section [Il.—HYDROGRAPHIC AND PLANKTON WORK IN THE ENGLISH CHANNEL. In August, 1908, the southerly flow of comparatively fresh water from the Irish Channel was well marked, and the salinity at Station 4, near Parson’s Bank, was much lower than in mid channel on the line from Plymouth to Ushant. Any division into layers of varying salinity was less than might have been expected during this month. By November salinities had increased everywhere in the English Channel, and were nearly the same from surface to bottom. In the Trish Channel, however, the salter water normally found under the north coast of Cornwall had spread some distance seawards, under the influence of strong easterly winds, as a thin surface film. Hydrographic investigations had, at the end of 1908, been carried out in the English Channel for six years, and had shown that the water eastward of Start Point is nearly always of the same composi- tion from surface to bottom. In view of the fact that surface water samples are collected every fortnight on four cross-Channel steamers, it was decided to confine the work eastwards of a line drawn from Start Point to the Channel Islands to surface observations only, and to add seven other stations to the westward of the area usually investigated. Five of these new stations lie on the eighth meridian, and No. 37, the most southerly, is a short distance beyond the edge of the continental plateau. The depths here vary very irregularly, but soundings of from 400 to 500 fathoms are to be expected. The February cruise of 1909 was the first made under the new pro- gramme, The water was everywhere nearly homosaline: at Station 37 the salinity was 35°53 °/,, at all depths down to 450 m. (246 fthms.). Unfortunately the wire was not long enough to allow of observations below this depth, and no bottom was found. The observations in the Irish Channel in May, 1909, show rather complicated conditions, a thick layer of salt water being here super- imposed on one of lower salinity. It is probable that this distribution is due, as in November, to strong easterly winds. At Station 37 the conditions were the same as in February, with the exception that the temperatures were slightly lower, and the surface layer had risen to 35°61°/,, salinity. On the bottom, however, which was not reached in February, the water had a salinity of 35°62°/,, and a temperature of 13°. The high bottom salinity has been noticed by several observers, and is generally attributed to a current from the Mediterranean. Until further confirmation is forthcoming, however, the high temperature must be considered doubtful, as it was measured REPORT OF THE COUNCIL. 497 with a single reversing thermometer, and these instruments ought to be used in pairs, owing to their lability occasionally to give incorrect readings. Samples of Plankton have been taken as usual on the quarterly cruises, and also at fortnightly periods on light-vessels on the southern and western coasts, and by the s.s. Devonia midway between Plymouth and the Channel Islands. Weekly samples have been taken at Plymouth. The records of species caught on the quarterly cruises are published in the Bulletins of the International Council. Zooplankton was very abundant in May, August, and November, in the Bristol Channel and around the Scillies. During May, Pseudo- calanus preponderated in the samples from this region. In August and November, Calanus was present in greater quantity at the western stations. A new species of Tintinnus, which first appeared at E. 20 (off Start Point) in November, 1907, was found occasionally during May, August, and November, 1908, at isolated points from 8.W. of Milford, through the English Channel, to the eastern stations, while a few specimens were taken in a netting from Longsands, in the North Sea, during August. Noctiluca appeared off Milford in May, 1908, and was abundant in the Bristol Channel in August. It gradually spread eastward during November, and has been found very thickly distributed in the mouth of the Channel and at Plymouth during February and May, 1909. During the year no less than five species of Ceratium, characteristic of warm seas, have been taken as far east as the Casquets area. Four were taken in February, 1908, west of Ushant. In May, one of these species dropped out and another appeared in its place. Two were taken in August and four in November. One species appeared off Milford in November. Observations have been made on the food of Noctiluca, and records kept of the diatoms found in them at various times. 498 REPORT OF THE COUNCIL. Published Memoirs. The following papers, either wholly or in part the outcome of work done at the Laboratory, have been published elsewhere than in the official publications of the Association :— Downina, E. R.—The Connections of the Gonadial Blood Vessels and the Form of the Nephridia in the Arenicolide. Biological Bulletin, vol. 16, 1909, pp. 246-258. GAMBLE, F. W.—The Influence of Light on the Coloration of Certain Marine Animals (Hippolyte, Wrasses). Transactions Manchester Literary and Philosophical Society. January 12, 1909. Goopey, T.—A Further Note on the Gonadial Grooves of a Medusa, Aurelia Aurita. Proceed. Zool. Soc., 1909, pp. 78-81. Martin, C. H.—Some Observations on Acinetaria. Quart. Journ. Mier. Sci., vol. 53, 1909, pp. 629-664. Donations and Receipts. The receipts for the year for the ordinary work of the Association include the grants from His Majesty’s Treasury (£1000) and the Worshipful Company of Fishmongers (£400), Special Donations (£273), Annual Subscriptions (£114), Rent of Tables in the Laboratory (£55), Sale of Specimens (£441), Admission to Tank Room (£120). The following is a list of the Special Donations :— Colonel W. Harding G. H. Fowler, Esq., PH.D. E. T. Browne, Esq. . : John F. P. Rawlinson, Esq., K.c., M.P. A. E. Shipley, Esq., D.SC., F.R.S. The Duke of Bedford, kK.c. W. Ambrose Harding, Esq. E. Waterhouse, Esq. Lord Avebury, F.R.8. The Earl of St. Germans The Right Hon. A. J. Balfour, MP. Professor A. Bevan . R. Gurney, Esq. EK. H. Parker, Esq. F. G. Sinclair, Esq. Ay jon py ps eS FEW RG) RS) SS Sy SH i S Ne SSJS SS Cer Gl Ol S are (oe ont ny SU ie ) So eo eo ee —2 on S pat ro) ASE eek (oo 0 pena nares SRS nS te bo ~l oS So | REPORT OF THE COUNCIL. = 499 Vice-Presidents, Officers, and Council. The following is the list of gentlemen proposed by the Council for election for the year 1909-10 :— President. Sir Ray Lanxkester, K.C.B., LL.D., F.R.S. Vice-Presidents. The Duke of ABERcorRN, K.G., C.B. The Duke of Breprorp, K.G. The Earl of St. GERMANS. The Earl of Duct, F.R.S. Lord Avepory, F.R.S. Lord TwrrpmoutaH, K.T. Lord WatsineHaM, F.R.S. The Right Hon. A. J. Baurour, M.P., F.R.S. Members G. L. ALwarD, Esq. W. T. Catan, Esq., D.Sc. Prof. A. Denpy, D.Sc., F.R.S. Sir CHARLES Extot, K.C.M.G. G. HERBERT Fow er, Esq., Pu.D. F. W. GamBte, D.Sc., F.R.S. Prof. WALTER GARSTANG, D.Sc. S. F. Harmer, Esq., Sc.D., F.R.S. The Right Hon. Joserpa CHAMBER- LAIN, M.P. The Right Hon. Austen CHAMBER- LAIN, M.P. A. C. L. Gunter, Esq., F.R.S. Sir Joan Murray, K.C.B., F.R.S. Rey. Canon Norman, D.C.L., F.R.S. Epwin WateruHovuss, Esq. of Council. | | | | Commander M. W. CamMpBELL HeEp- wortTH, C.B., R.N.R. E. W. L. Hott, Esq. J. J. Listrr, Esq., F.R.S. P. CHALMERS MitTcHELL, Esq., D.Sc., F.R.S. Epa@ar Scauste|r, Esq., D.Sc. Prof. D’Arcy W. THomeson, C.B. Chairman of Council. A. E. Saipiey, Esq., D.Sc., F.R.S. Hon. Treasurer. J. A. TRAVERS, Esq. Hon. Secretary. EK. J. ALLEN, Esq., D.Sc. The following Governors are also members of the Council :-— G. P, BrppEr, Esq., M.A. E. S. Hansoury, Esq. (Prime Warden of the Fishmongers’ Company). E. L. Beckwitn, Esq. (Fishmongers’ Company). Sir. RicHarp Martin, Bart. (Fish- mongers’ Company). Prof. G. C. Bourng, D.Sc. (Oxford University). A. E. Sarprey, Esq., D.Sc., F.R.S. (Cam- bridge University). Prof. W. A. Herpman, D.Sc., F.R.S., (British Association). Dr. Statement of Receipts and Payments for = Ce al £ eh To Current Income :— H. Mi. Dreasuiny 7 s2eceecs. se.easananntaee treme ateaeeten 1,000 0 0 Bishmongers' (Companyccccssessessoeeceesesactee reenter 400 0 0 ANAT USHMAN NNOTAS 6 cope consedosuonnapsoccecopponbennononTe ily 2) © Rentyof Walles: crass gasneconstec.seaseuhdecataeenassaanneene yy ILO) to », Extraordinary Receipts :— Donationsjasiper WepOGbans-csceenssseeete ee eeeeaatnsee reais 273 0 0 ,, Charter of Steamboats :— SiS ¥iaunley efor halfey Carat stn, eae ceccuttessdserenterecete 300 0 0 S.8. Ozthona, for special voyage... .n.c.0cerecrecsssercesne 2a 0) O 325 0 0 5, Special Grant from the Fishmongers’ Company made in advance to qualify Sir Richard B, Martin as life aeKerEOVOTSIO COVe HONS) COMUNE po dancnosoos sonddosdE oranausscAcK 500 0 90 £2,668 14 0 Examined and found correct. > (Signed) N. E. Warrnnovse, A.C.A. Antuur DENDY. W. T. CALMAN, L. W. BYRNE. 30th June, 1909. the Year ending 31st May, 1909. Gr. £ s. d. £ s By Balance from last year, viz. :— oan iromeaBaulkpaasesesccotensies «nicer nce eceaersere sssaecteis 700 0 0 Wess Cashwat i anke sam, smdenaataconesceeaceess £437 5 7 @ashyindhan Geserann sche scaasteceu sans alte) ae) ala 456 5 6 243 14 5, Current Expenditure :—- Salaries and Wages— Dir CCbOPe ras dacssassiesedeosestudseetess accucdghoadussendodan ote 200 0 0 PASSISEAN UE DMC CEOUT Was aays vate sieicen sng ww eanantvatcplyares asia 200 0 0 NGGUIT AIST eepeeeties eteeer sneha cee ee cscckeneeteccretesccere rs Higftay. (0) al SS MAMIOSs aN eC OSiew.cae-cinste GoedssaneoatacoansncSasesaanonde 391) 0 2eee ele zien dinavellimes Bix penSese tcc csuisssseascteten tyes cleries er gasducesensuac = 47 5 PA aVereremeced semeweccteacnecrceG as seeiassoeaach cetiosteies Hoseesaae TOTES AIOILIA TE; Ade cooeh odeminc Rag D SESE SCORER ASnCn TAT Ra Cee iCo Re pon ennatIone 132 11 3 JUGS SEMGEE ORO W800 bree Anadeedaan sone coer eaooneonacanS nantes 2B) iy GI 108 13 Buildings and Public Tank Room— Casey jatemmandeCanllernenadescckassens aden iwanecteh ce sumeene 07a 126 StockimosNanks: sMeedine ete. aajecsessascesass sons seeceens yy ay Mainiemancerand RenewallS\s5,.cc.ces sce seem -cececs eves vs.cn's Cll omne, Rent of Land, Rates, Taxes, and Insurance ............ 39 17 8 Amik 3) 0 ECsse NT TOISSIONELO eam ke At OOM ey aa. e sense atin secateee 120 010 141 8 Laboratory, Boats, and Sundry Expenses— aie: Stationery, Office Expenses, Printing, etc................ 155 8 7 Glass, Chemicals, and Apparatus......... £160 6 10 JEESEISENGSS. Sa nbesudeae dda oactennesen oe ance 46 0 0 114 6 10 BULEMASe Ol SPECIMENS: ...6.:t2n..cvurderearevacaesesetnsacns 55 14 4 Maintenance and Renewal of Boats, Nets, Gear, etc , exclusive of s.s. Huwley £173 14 9 SUES: SNES Ee 8 Axe cact ge poouetonacteruncocnccace is} iE al yey (0) 45) Insurance of Steamers— SLI 02 EAA as onutennen bbs cosceennbec core aednes 22ley al SS OULILOT Dirac cones sectaceciat acs deseo sonar tet 20138 7 236 4 10 Coal and Water for Steamers, excluding s.s. Hualey 98 3 6 814 18 9 BESS NANE Ole SPECIMENS CLCh see naseserencseedecsssee cone ce 441 2 11 873 15 Bamilealinbenes tyencn sehocenr sees ceseiteossstawensess ancveseicaececes 14 11 », Extraordinary Expenditure :— Purchase of s.s. Hualey— Second instalment of purchase price ..................65 lisa) (0) 0 ANGELES PRON WHOA Es Saremen ae cmmeic ta dis fosmoncm cer ne tas eg aise NG fy 7 Ua (The balance of the purchase price is secured by a Mortgage of the vessel repayable by annual instalments.) By Balance, including Special Grant of £500 per contra, applicable to the years ending 31st May, 1910 and 1911 Washvabr Bak can v desta savaensscne sdesterrachanseie dneeatieneess 713 10 3 WS himiTinh an deen sca seecocecsimcasestee sae wcetseeesaaek ce heactins 4 23 (27 12 6 ieSSMIBOATIAGUC LORAIN sees sc oes aveocssteecse aenmeonweeeees's 500 0 0 227 12 This Balance is apportioned as follows :-— rs AF CTIET USAC COUN beste aenie sie cece severccaenae eau a5, 09) Gl Repairs and Renewals Account............ See lee 227 12 6 £2,668 14 er oO Co sI to “I An Experiment in the Transplantation of Plaice from the Barents Sea (“ White Sea”) to the North Sea. By George T. Atkinson, Assistant Naturalist at the Lowestoft Laboratory. Asovut midnight on 26th June, 1908, at the close of a voyage to the White Sea fishing grounds, undertaken by Mr. A. E. Hefford and myself in the Hull steam trawler Princess Lowse, H 837, Captain Turner of that vessel did me the great favour of taking a short haul to procure plaice for transplantation to the North Sea. OBJECT OF THE EXPERIMENT.—The object of this experiment was to test if it were possible for plaice to survive such physical changes as are necessarily involved in this great change of habitat, and to see further if they would display any feature of growth. The result has been that not only do the fish appear to have survived, but they have grown in a most remarkable manner. The rate of growth shown by the last five specimens recaptured is much greater than that of North Sea plaice of the same sizes and sex, which have been marked in the same way and set out again on the grounds where they have been caught. The growth has been many times faster than that indicated by the otoliths of plaice in the portion of the Arctic Ocean from which they were brought.* This unusually rapid growth has been accompanied by considerable improvement of the fish as a marketable commodity. The object of the voyage in the Princess Louise was to continue the investigations, commenced in the oman, of the conditions of the plaice fishery in the Barents Sea.t It had been arranged to again accompany the Roman, H 948, but as Captain Leighton sailed a day earlier than was intended, he kindly arranged for Mr. Hefford and * Asan illustration of the extremely slow growth which obtains in these northern waters, I have in my possession a photograph by my colleague, Mr. R. A. Todd, of ten otoliths of as many fish of the VIII group (in these cases fish just nine years old), five of these fish are from the North Sea and five from the Barents Sea; 47, 48, 52, 52, and 54 cm. were the lengths of the former, which were all mature females: the lengths of the latter three im- mature females and two mature males were only 30, 30, 32, 27, and 29 cm. + Journ. Mar, Biol. Assoc., VIII, 1908, p. 71. TRANSPLANTING PLAICE FROM BARENTS SEA TO NORTH SEA. 503 myself to leave Hull with Captain Turner and to transfer to his own ship on the fishing grounds. Unfortunately we were unable to meet as arranged, and this mishap deprived us of the use of two tanks which I had sent on board the Roman.* Had these been available a larger number of fish could have been as easily dealt with. To take the place of these tanks, there were improvised five tubs, made from halves of the casks which the trawlers take to sea for the reception of fish livers. Each of these was scrubbed out and filled with water to the depth of eighteen inches, holding in this manner 15-20 gallons apiece. Changes of water were effected by means of buckets and the use of the ship’s hose at intervals. This primitive method was continued during the seven days occupied in steaming 1540 miles from the Barents Sea fishing grounds to the N.W. Rough of the Dogger, where the twenty-three surviving fish were marked and liberated. A much larger number had originally been placed in these tubs, but owing to the very limited space available and the lack of means for adequately changing the water the mortality at first was very heavy. We were fortunately favoured with moderate weather for the journey, except for some hours after coming out of the Norwegian fiords by the Lofoten Islands. Here the vessel, driven full speed in the face of a strong head wind, had the main deck frequently swept by the seas from the bows to the winch; however, the fish appeared to sufier no inconvenience and the tubs received no damage, being lashed on the after deck. Besides my colleague Mr. A. E. Hefford, and Captain Turner, I have also to thank the chief engineer of the Princess Lowise, Mr. Gardner, to whose resourcefulness in providing the tubs, and to whose interest, the successful issue of the experiment was in great measure due. CHANGES OF TEMPERATURE ON THE VOYAGE—One of the most strik- ing changes accompanying this journey south was naturally that of the temperature of the water in which the fish were being kept alive. On June 26th, on the fishing grounds, the bottom temperature varied between 34° and 35° F., whilst that of the surface was between 37° and 38° F. On June 27th, before reaching Nordkyn, the temperature was between 40° and 42°3° F., and on the 29th, at Tromsoé, had risen to 45° and 47:0", and reached 48°9° on the 30th, 49°5°-52-0° on July 1st, * I suggested to Captain Leighton that he should on the following voyage attempt to bring back some living plaice in these tanks, and brought to his notice the precautions to be observed to, obtain a successful result. In correspondence he informs me that he left the White Sea fishing grounds with about sixty fish, of which forty-two were alive on his arrival at the Humber. These were then iced and finally distributed amongst the members of the crew. NEW SERIES. —VOL. VIII. NO. 5. Marcu, 1910. 2M 504 AN EXPERIMENT IN THE TRANSPLANTATION OF PLAICE FROM 54°3°-55'7° on the 2nd, and on July 3rd, up to the time of setting out the fish, the temperature had ranged between 54°5° and 580° F. The extremes of temperature these fish experienced thus ranged over 24° F., without their appearing to have suffered from the rapidity with which the changes occurred. RECAPTURE OF THE FisH.—The following table gives particulars of the recapture of the individual fishes (see next page). The object in selecting the N.W. Rough as the point of liberation for these fish was that, in addition to being in the direct track of our vessel between the Norwegian and English coasts, it was a ground which offered a fair prospect of some of the fishes being returned if they survived. Unfortunately some Grimsby, Hartlepool, and Scar- borough trawlers, engaged in fishing for cod and haddock, chanced at once to visit the area of liberation, and in the first month eight fish were returned. Five more being subsequently recaptured gives the result that within one year 15 or 56°5'% have been returned. The latter five were caught in the fourth (two specimens), seventh, tenth, and eleventh months after lberation, and without exception show important and unusually rapid growths compared with those which have been observed in the case of North Sea fish of correspond- ing size and sex. These growths were accompanied by considerable improvement in the condition from the point of view of the market value of the fish. MOVEMENTS OF THE FisH.—A feature connected with the move- ments of the last five fish is that all but one had migrated from the deeper water (33 fms.) in which they were liberated, short distances on to the Dogger Bank (20 fms. and less). The furthest migrant was E 3880, which was taken on the Eastern- most Shoal, about sixty miles from the point of liberation. Another fish, E 3876, had moved about forty miles in the direction of the Middle Rough and was retaken by a Dutch steam trawler. It is curious to note that the Grimsby trawler which effected the recapture of the former specimen also took, at the same spot, a plaice (HZ 778), which I had myself transplanted to the Dogger from the Dutch coast in May, 1907. This fish had grown 18:5 cin. All the female fish brought from the White Sea appeared to be im- mature, the contrast between such and spent ones, so soon after the northern spawning season, being in most cases very marked without internal examination being absolutely necessary.* * A new feature in the biology of the plaice lies in the enormous depth at which the Barents Sea plaice spawn. In May, 1909, Captain Leighton informs me, they were found by our trawlers to be in spawning condition in great masses in 90 to 106 fathoms. ‘paungdeoar uvaq Apvalye aAvt] TOUT YS Ye) i ayy Jo % oF ‘SooUBISUT XIS UL pazOU SsaTatPIOAOM B1OM SMOISBIGE LETTS (% oz) SOOWEISUL UAVS UT Worye1eq!] JO SUIT} oy} 4B pozoU o10M SUOISRAGE USS FV} esayy Jo pajou oq Avut 4, ‘F.9P 6 ZESE AM * 4-98 P LOSE A +6.68 d SB8EH *8.16 5 OSVEM *S.LE P GB8E HW {L.pe 9 ossem 60-88 5 GISEA ‘196 d SI8EU *9FE P LIBEH *F-FF 5 GI8E A oe Aploqiy YV [[S o1v AO parp oavy YoryA Ys “UOTPLIOGT] WO .,§ “W,, PAJON “OUUT} SAL aT{} AO oAMYLUT 07 SuroUdUTUIoD ATJUoIeddy “yey Ata A *(0) ‘plo savok y Ayquowwddy "841 | oorryg sv uorztsod omes ut pur ‘Avp owes uo “yvoq outvs Aq yySuRD *(q) = "Wd Tp ‘YyQsueT opquqoad ‘poseuep sXva prey, ‘apeqs Ata *(v) we “SALON io) eee oe ees iy eee Ee : ee ; 3 =] S 72) (A4S | ) GEL 6-09 G-GP "12998 AD | “GSP 1 “1G 29 | 0G-LT windg wo ‘GN softtt Gol | g48e A | 0% eunpo = GTS] ? OL 6-68 6-68 Wy 498 AD or 0Z-81 ‘H0G ol “N,JG .b9 381 | SESE A | FL APT ce 6a. | “dsp ©g601 6-19 Gg. &P 48 AD = Gg "H,G .. N,0G bg “JT | p8sea | 46 “49a =e GO6T o ‘ a él é oh 9.68 8.48 "14-48 AD faa IL ‘HGP 6 N66 bo ‘IVT | O888H | 8t “4 — 9G >} ? 06% L-86 v-FS | WET 4 4S GUNG == 06 "H 0G 6 “"N,0Z 69 “381 | 91860 | 9 “AON 5 Ze eo | ‘dsp D68G gace 6-&E -- | == ho = (&qsuts “wooo uo punoq) | 0688 A | 94-2‘ a AT “UT } LOF 1.96 9.96 1} IS TH | “1,89 0 ',79 SG | 08-86 joodeaey Jog eH som gy) | T188H | 0a <* Rn OL “wd 6G (+P-6& 1.1¥ “It IS TH | “1,89 .0 “7G .b9 0& joodojyieyy Jo SEA satu gy, | pAseH | er “4B 3 6 | “urd | Sege | 1.78 | Gags "1498 AD = as “A 2G ol “N,2G opG “FBT | S888 | ot a 8 “ds 2 9bP 8.68 | &.0F "48 AD | a eek EUR Be SK Aefeeha FPG hy oC fed) Eo = a) ? 608 LE €-GE Ee: | ag baer (Aqswitt) ‘uooyuog wo punog) | esse a | 6g * = g P TL8 8.68 | 1-58 “14 ‘48 HS = ag ‘0. N,0 99 1 | Le88H | 9 Ly G fs) 16h | 8.9& 8-1E “4-48 AD ar: OV OT ot NFL ogo PT | Glee |g —Atur | SO6L ates *[aqUry aay deooy I a ae puv xeg | qysIeAy oat A fens pue [esso, WOVEN} EL ENEMMEMO) | ravster gy peytodey Aqieo07 JOON jo ey a ca a le a S SAME 2 Ney Bhs ee lS es ee nt le 2 oS 2 ee ee eee I : a AUALd VOU AO SUVTINOILYVd = ‘Sa]IU QFEL "vo sqng urskep J pattavo : ‘su pH AES IP NO 69 FT “Bog syusivg wo pozurpdsuvdy, 2 ‘sup Se HL OT oN ,8 49 “WIT “(e688 A-1L8e W) orTd 2 “806T ‘prs A[ne ‘“NOILVUAAIT AO SUVINOMLYVd ‘poqyuvdsues} oorepg oy Jo eangdvoor pue uoryetoqiy Jo saepnotjaed oy SuULMOYS oTQeI, PCC RAL 506 AN EXPERIMENT IN THE TRANSPLANTATION OF PLAICE FROM All the males, on the other hand, were above the average size at. which this sex is found mature in the Barents Sea; two were actually found to be spent on being returned to the Laboratory after a few days of liberty. This fact makes the growth observed all the more a matter of surprise, as we usually find large male plaice grow very slowly. * E 3884, caught in February, was observed to be recently spent, and had thus taken part in one reproductive period in the North Sea. The ovaries of E3875 were such as one observes in female plaice which are apparently maturing for the first time. On the basis of these last five fish, as discussed below, it would be absurd to attempt to base any definite conclusions. In discussing them, the main desire is to bring to notice the suggestive results that this small experiment has attained, so that when the opportunity again arises similar experiments may be attempted on a larger scale, since it can no longer be doubted that a rational development of the plaice fishery of the North Sea would be possible under a carefully planned scheme of transplantations. Below have been drawn up a few notes on the changes of which the last five fish returned have given evidence, regarded from the following points of view :— . 1. Increase in size. 2. Increase in weight. 9 3. Increase in value. 1. INCREASE IN SizE—The eight fish caught in July all show a slight shrinkage, as is usual in marked fishes retaken shortly after liberation. It is usual with some investigators to estimate shrinkage between death and remeasurement at 0°5 cm., but in order to depress the observed growths rather than to exaggerate them this convention has been disregarded throughout. The two specimens reported in November had increased in length from (male) 34:4 to 38:1 cm., and (female) 35°8 to 39°6, or 3°7 and 3°8 em. respectively. The next fish was retaken in February, and the growth from 43°5 to 47°3, or 3°8 cm., is a very rapid growth for such a large male. Another male fish came back in May, and had increased 6 cm., from 33°9 to 39°9 cm. The last fish returned gives an astonish- ing increase for so large a fish, having grown from 42°5 to 50°3, or 78 cm. (female). * It is interesting to note in comparison with this experiment, that Strodtmann trans- planted plaice from the Baltic to the Elbe L.V., making the passage to the North Sea through the Kiel Cana]. These were chiefly mature fish, and though many were retaken very few had grown at all after several months in their new surroundings, Cf. Reichard, Die deutschen Versuche mit gezeichneten Schollen II, p. 34. THE BARENTS SEA (“WHITE SEA”) TO THE NORTH SEA. 507 How rapid these individual growths are in comparison with those of the North Sea fish can be seen by reference to any published report. To illustrate this rapidity, a number of records have been taken from the English marking experiments in various localities in the North Sea. These have been put together in the form of a table, and fish have been chosen which mostly resemble the five White Sea plaice in original size, the sex being of necessity also the same. At the head of each of five columns is given the label number of the White Sea plaice with its original size, growth, and number of days at liberty. Below each comes a list of North Sea fishes marked in the same way, and set out again in whatever part of the North Sea they happen to have been caught. Comparison can thus with ease be made by taking any of the North Sea fish and comparing the growth, or period at liberty, given at the top of the column :— TABLE IL. Table showing growth in the periods stated of normal North Sea marked plaice to compare with five specimens transplanted from the Barents Sea. E 3876 6 34-4 E 3880 2 358 E 3884 ¢ 48°5 ] E 3893 3 33°9 EB 3875 2 42°5 grew grew grew grew grew 3°7 em. in 126 days. || 3°S em. in 188 days. || 3°8 em. in 239 days. || 6:0 em. in 315 days. || 7°S em, in 352 days. Growth. | Days out. || Growth. | Days out. || Growth. Days out. || Growth. | Days out. Growth, | Days out. 0:4 83 iy 116 0:0 1 i) Oxo) 82 0°4 1438 eel opie: —0°2 148 =i) a 136 0°9 119 0:2 142 0°8 97 0'1 176 : : : sar lle : 01 197 1:4 141 1:0 Pat | 0°3 162 || ono 112 heats 212 40) 2 |) ale 1:0 154) Li) 058 230 2°4 TCI | hee lhl 234 a ‘i || : | : OL 7, 282. 0°7 195 Dae 156 09 | 286 0°3 123 0-7 296 1°9 196 1:0 183 1°3 293 0°6 142 16 314 fae | x : : A ze 2°0 326 10 252 a ite) 193 0°53 | 314 | 2°0 262 1:8 350 ; 42 = 4 é : | 4°3 353 2°6 292 2°9 272 0°8 321 0:2 | 267 1°4 360 ‘ ; Ba ’ : 1°6 414 3°0 273 aa) 277 al 340 3°4 287 3°] 450 4°4 275 3'1 361 Osi = Bho) 4-7 315 2°5 458 : : 4 . ; 2°9 462 1°9 293 4°9 373 0°5 | 410 2°5 338 21 469 . ; | - y 4°0 487 5°4 453 81 618 | 31 676 1°6 453 13 489 0°3 481 10°0 649 | | 4°3 462 1'0 498 12 506 || 441 802 | | 3-1 eigen any | | S 09 511 7 1°4 556 | | 4°2 Be 6-2 564 | | | A 5'0 596 | = She 1-4 680 I 4°3 839 5'6 781 ekKNv“ww—"—5. —__ __ _* ——_— All originally All originally || All originally All originally All originally $ 34:0—35'0 em. || 9 34°9—36°5 cm. || 6 39°0—42°7 em. || 6 33°0—33°9 cm. || 2 39°0—44°7 cm. er ee Ee 2M2 508 AN EXPERIMENT IN THE TRANSPLANTATION OF PLAICE FROM a Although the above lists are not exhaustive and the growths quoted have been taken more or less at random, it can be clearly seen how slowly North Sea plaice of the stated lengths grew, as compared with these fish transplanted from the White Sea. As compared with the first transplanted plaice only two growths of North Sea fish are noticed to be in excess, and these individuals had been at liberty respectively twice and three times as long after marking. Comparing the growth of E 3880 with that of similar sized North Sea fishes, we find it only surpassed by specimens which have been out twree, nearly thrice, four and a half, and nearly six times as long. No growth is observed to equal that shown in the case of E 3884, 3893, or 3875, though some of the periods of liberty are more than twice as long. These growths are truly remarkable, in consideration of the prob- able age of the specimens concerned, and in view of the slow growth old plaice have been frequently shown to display. It may be mentioned that further, but incomplete, investigations of the otoliths of the smallest plaice yet found on the White Sea grounds amply bear out the indications of slow growth afforded in my earlier report. 2. INCREASE IN WEIGHT.—AII the fish have been weighed after their recovery by the fishermen, but, as the relation between length and weight of White Sea plaice in their normal condition is unknown at present, it is not possible to state exactly by how much the last five individuals have increased their bulk. In view of the additions which have been demonstrated as regards length, and in view of the fattened condition of the fish, the weight increments must have been very con- siderable. A tentative estimate can be deduced from the following data. The weights of the eight fish caught in July compared with the average weight of Dogger plaice of the same sizes determined by Masterman* show deficiencies amounting to 17°35, 23°5, 41°5, 38-1, 29:1, 31°0, 22:9, and 26°8 per cent respectively. The average deficit amounts to just under 29%. It cannot at present be said how closely this determination displays the actual deficiency in condition for which the White Sea plaice are noted, but it at least has the merit of bearing out the experience of practical men as to the inferiority of these fish as compared with those from the North Sea. * Report on the Research Work of the Board of Agriculture and Fisheries in relation to the Plaice Fisheries of the North Sea. Cd. 4738. London, 1909. THE BARENTS SEA (“WHITE SEA”) TO THE NORTH SEA. 509 I propose to estimate the increase in weight of the five fish re- ferred to on two bases :— A. That the original weight of each fish was equal to that of a normal Dogger plaice. B. That the weights thus obtained (A) are on an average 297% too high, as was ascertained for the July fish. Estimate A: for the original weight being obviously too high, we can be satisfied that any increase shown on this basis is below that actually attained. It is further possible that increments based on Estimate B understate those actually attained. The resulting figures are given in Table III below. TABLE III. Table showing estimated increase in the weight of five plaice transplanted from the White Sea to the North Sea, based on two estimates of their original weight. A. That the plaice were equal in weight to Dogger plaice of corre- sponding sizes. B. That estimate A gives an original weight value 29% too high in accordance with observations made on eight fish in July, ; r ‘Estimated Original Weight. Increase in Weight. %, Inerease,. Seer Ultimate Weight. aa A. B. Estimate A | Estimate B.| Est. A. Est. B. E. crammes. crammes, grammes. grammes, grammes, | , L, 3876 | 485 344 590 105 246 | 21°6 fs 3880 528 315 | 742 214 367 40°5 97°6 3884 | 843 599 1095 252 496 29°9 82°8 3893 | 405 288 | 702 297 414 73°3 VAS 7 3875 813 577 1535 722 958 88°8 166°0 | | | From this table it can be seen that, on the lowest possible estimate, the two fish which had been at liberty the longest (and this period less than a year and including a winter) had increased by about three- quarters of their original weight (73°37 and 8887); the fish which had been at liberty shorter periods also displaying corroborative increments. The data are too small to permit of further discussion, but by kind permission of my colleague, Dr. Wallace, I am able to put forward in contrast to the above figures data from his forthcoming report. Dr. Wallace finds from otolith investigations that, as regards the plaice of the Dogger and Flamborough region, the weight of six-year- 510 AN EXPERIMENT IN THE TRANSPLANTATION OF PLAICE FROM old males (average size 37:0 cm.) shows an increment of less than 30% on that of those five years old, whilst the seven-year-old fish of this sex, having an average length of 38:1 cm., show less than 107 weight increment on fish a year younger. This oldest group is, how- ever, not sufficiently well represented for this result to be regarded as more than approximate. Dealing with the females, the six-year-old fish (average size 41:0 cm.) are found to average a little over 407 heavier than those of five years, and the seven-year-old fish (average size 44:1 cm.) show an increment of just over 20% as compared with the six-year-olds. Referring these figures, which are based on abundant material, back to the percentage weight increments of Estimate A in Table III, the indications in this table present a truly remarkable contrast in favour of the probably older plaice transplanted from the White Sea. 3, INCREASE IN VALUE.—The plaice fishery in the Barents Sea has only been conducted by our trawlers during four summers, and it would be premature to discuss the values of the product. These, however, have been adversely affected by two important considerations, the somewhat poor quality of the fish combined with excessive supplies in the summer months. A trade expert giving evidence before the Committee on Fishery Investigations expressed an opinion that the plaice sell at less than one- tenth the value of any other plaice (Committee on Fishery Investiga- tions, 1908. Minutes, Ud. 4304, p. 391). The White Sea plaice have not the coarse, dark appearance, which used to characterize the old, accumulated stock at Iceland, and would, after a few months fattening in the North Sea, be indistinguishable in. external appearance and doubtless too in food value from the indigen- ous population. Thus, if we may assume that each of the last five fish would have doubled its weight had it been at liberty a year, and basing the value of White Sea plaice at one-fifth that of North Sea plaice, each would have been worth at least ten times the price usually obtained. . It would be absurd, on the slender though corroborative evidence of the above results, to suggest that the transplantation of White Sea plaice wouid be practicable as a commercial undertaking. At the same time it must be admitted that even this would prove sounder economy as regards the development of the White Sea fishery than is the present plan of converting many tons of this valuable fish species into manure, as was done in the great gluts in the summer of 1909, The fact that plaice can be carried in safety such long distances and through such varying conditions, broadens the question of trans- THE BARENTS SEA (“ WHITE SEA’) TO THE NORTH SEA. 511 plantation. Might not, for instance, plaice be carried across the Atlantic and introduced to the Canadian coasts and the Banks of Newfoundland, where its congeners in other waters, the cod, haddock, and halibut, already occur? Or, again, might not the very small halibut, which have been brought to market by the trawlers in vast quantities from certain parts of Faxe Bay, Iceland, also be brought alive and set out on the North Sea grounds, where this valuable species was without a doubt much more abundant formerly than it is to-day? Such, and many practical questions of a similar nature, proffer a wide field for future research. PUBLICATIONS OF THE ASSOCIATION. + a Sree Journal of the Marine Biological Association. OLD SERIES. No. 1, Aucust, 1887 (only a few copies left, reserved for Libraries). No. 2, AuGcust, 1888. Price 1s. New Series (Royal 8vo). Volume I., 1889-90, 472 pp., 28 plates. Volume IT., 1891-2, 410 pp., 14 plates. Volume III., 1893-4, xxxvili. and 458 pp., 5 plates and 25 woodcuts. Volume IV., 1895-7, iv. and 425 pp. Volume V., 1897-9, 550 pp. and 16 plates. Volume VI., 1899-1903, 676 pp., 3 charts and 7 plates. Volume VII., 1904-6, 588 pp., 1 chart and 12 plates. Volume VIII. Nos. 1, 2, 3, 4, and 5. Separate numbers (generally 4 to one volume), in wrappers, from 1s. to 5s. each, according to size. London Agents: Messrs. Dutau & Co., 37 Soho Square, W. Cloth 4to, 150 pp., 18 plates (12 coloured). A TREATISE ON THE COMMON SOLE. BY J. T, CUNNINGHAM, M.A. F.RS.E., Late Fellow of University College, Oxford; Naturalist to the Association. Price to Members, 20s.; to Non-Members, 25s. Medium 8vo, 368 pages. 159 Illustrations and two Maps. Price 7s. 6d. net. (Macmillan & Co., London.) THE NATURAL HISTORY OF THE MARKETABLE MARINE FISHES OF THE BRITISH ISLANDS. Prepared expressly for the use of those interested in the Sea-fishing Industries, BY J. T. CUNNINGHAM, M.A, FORMERLY FELLOW OF UNIVERSITY COLLEGE, OXFORD ; NATURALIST ON THE STAFF OF THE MARINE BIOLOGICAL ASSOCIATION. GGith Preface bp E. RAY LANKESTER, M.A., LL.D., F.B.S., PROFESSOR OF COMPARATIVE ANATOMY IN THE UNIVERSITY OF OXFORD. PUBLICATIONS OF THE ASSOCIATION. cee ee Journal of the Marine Biological Association. OLD SERIES. No. 1, August, 1887 (only a few copies left, reserved for Libraries). No. 2, Aucust, 1888. Price 1s. New SERIES (Royal 8vo). Volume I., 1889-90, 472 pp., 28 plates. Volume IT., 1891-2, 410 pp., 14 plates. Volume IIT., 1893-4, xxxviii. and 458 pp.,.5 plates and 25 woodcuts. Volume IV., 1895-7, iv. and 425 pp. Volume V., 1897-9, 550 pp. and 16 plates. Volume VI., 1899-1903, 676 pp., 3 charts and 7 plates. Volume VII., 1904-6, 588 pp., 1 chart and 12 plates. Volume VIII., Nos. 1, 2, 3, and 4. Separate numbers (generally 4 to one volume), in wrappers, from ls. to 5s. each. according to size. London Agents: Messrs. Dunau & Co., 37 Soho Square, W. Cloth 4to, 150 pp., 18 plates (12 colowred), A TREATISE ON THE COMMON SOLE. BY J. T. CUNNINGHAM, M.A., F.R.S.E., Late Fellow of University College, Oxford; Naturalist to the Association. Price to Members, 20s.; to Non-Members, 25s. Medium 8vo, 368 pages. 159 Illustrations and two Maps. Price 7s. 6d. net. (Macmillan & Co., London.) THE NATURAL HISTORY OF THE MARKETABLE MARINE FISHES OF THE BRITISH ISLANDS. Prepared expressly for the use of those interested in the Sea-fishing Industries, BY J. T. CUNNINGHAM, M.A,, FORMERLY FELLOW OF UNIVERSITY COLLEGE, OXFORD ; NATURALIST ON THE STAFF OF THE MARINE BIOLOGICAL ASSOCIATION. GGith Preface bp E. RAY LANKESTER, M.A., LL.D., F.R.S., PROFESSOR OF COMPARATIVE ANATOMY IN THE UNIVERSITY OF OXFORD. 7 sid lieh ae 1 dle al a A. Acanella arbuscula, 9. Acanthodoris pilosa, 238. — subquadrata, 239. Acanthogorgia ridleyt, 9. —(Blepharogorgia) schrammi, 10. Actinia, from the North Sea, 215. Liga Strémii, 195. Aigeon Lacazet, 413. Holidia papillosa, 228. Molidiella aldert, 229. —- glauca, 229. Aiquipecten opercularis, 365. Agluophenia myriophyllum, 34. Alcyonaria, from the Bay of Biscay, 6. Alcyonium coralloides, 6. — digitatum, 7. Algee, occurring in cultures, 463. Allen, E. J., Mackerel and Sunshine, 394. — and Nelson, E. W., on the Artificial Culture of Marine Plankton Organisms, 421. Amblyops abbrieviata, 193. Amblyosyllis lineata, 199. Amphihelia oculata, 13. — ramed, 13. Amphorina aurantiaca, 230. Anachis costulata, 385. Anapagurus levis, 416. Anarrichas (minor 7), See Catfish. Anchialina agilis, 193. Ancula cristata, 240, Anomia ephippium, 362. Antennopsis norvegica, 33. Antennularia antennina, 33. —- ramosa, 33. NEW SERIES.—VOL, VIII. No. 5. Antipatharia from the Bay of Biscay, 10. Arca nodulosa, 363. — obhiqua, 363. Archidoris testudinaria, 238. — tuberculata, 238. -— — rearing, 469. Arnoglossus laterna, 3. -—— lophotes, 3. Aspidophryzus peltatus, 196. Astacilla longicornis, 196. Astarte sulcata, 367. Asterionella japonica. See Plankton diatoms. Atelecyclus septemdentatus, 417. Atkinson, George T., Notes on a Fishing Voyage to the Barents Sea in August, 1907, 71. — An Experiment in the Trans- plantation of Plaice from the Barents Sea (“White Sea”) to the North Sea, 502. Autolytides inermis, 202. Autolytus ehbiensis, 201. — longiferiens, 202. — macrophthalma, 201. — pictus, 201. B. Balance Sheet, 1906-7, 68. 4 221807285838) — — 1908-9, 500. Barents Sea, Notes on a Fishing Voyage to the, 71. — Transplantation of Plaice from, 502. Bathynectes swperba, 417. Biddulphia mobiliensis, See Plankton diatoms. 514 Biddulphia regia. See Plankton diatoms. Bimeria, Wright, 19. Bimeria arborea, nova species, 15, 20. — biscayana, nova species, 15, 20, — (Garveia) nutans, 19. — vestita, 20. Bolocera longicornis, 216. — tuedie, 215. Boreomysis arctica, 194. Bougainvillia, 41. Brachiopoda from the Bay of Biscay, 392. Browne, Edward T., The Hydroids collected by the Hualey from the north side of the Bay of Biscay in August, 1906, 15. — A New Method for Growing Hydroids in Small Aquaria by means of a Continuous Current Tube, 37. Buccinofusus berniciensis, 384. Bucecinum sp., 381. — undatum, 380. Bullen, G. E., Plankton Studies in Re- lation to the Western Mackerel Fishery, 269. Byrne, L. W., The Fishes collected by the Huxley from the north side of the Bay of Biscay in August, 1906, 1. C. Calanus finmarchicus, rearing, 470. Calliostoma cleopatra, 360, 375. — granulatum, 376. — miliaris, 375. — obesulum, 360, 375. Calycella fastigiata, 24. Campanularia hincksiwi, 24. — raridentata, 24. Capulus hungaricus, 376. Cardium minimum, 370. — (Levicardium) norvegicum, 370. Caridion Gordont, 410. Caryophyllia clavus, 11. Castalia fusca, 350. Catfish from the Barents Sea, 96. Cavolinia infleca, 386. — trispinosa, 360, 386. Cerianthus lloydit, 225. INDEX. - Cheetoceras constrictum. See Plankton diatoms. See Plankton diatoms. See Plankton diatoms. — decipiens, — densum. Chetopterus variopedatus, rearing, 468. Chlamys sulcatus, 364. Chondractinia digitata, 224. Cirolana borealis, 195, — Hanseni, 195. Clio pyramidata, 386. Clytia johnstont (Alder), 24. Cocconeis scutellum, var. minutissima. Sce Plankton diatoms. Cod from the Barents Sea, 95. — hermaphroditism in, 315. Conger vulgaris, 1. Conger with abnormal gonad, 318. Corallium maderense, 7. Coryphella gracilis, 233. — lineata, 233. — rufibranchialis, 234. — salmonacea, 235. Coscinodiscus excentricus. diatoms. — Granii. See Plankton diatoms. See Plankton Crangon Allmannt, 412. Cratena amend, 231. Crawshay, L. R., On an Experiment in the Keeping of Salmon (Salmo salar) at the Plymouth Laboratory, 303. — On Rock Remains in the Bed of the English Channel. An Account of the Dredgings carried out by s.s. Otthona in 1906, 99. Oryptolaria hunuilis, 29. Cucumaria saxicola, rearing, 467. Culture of Marine Plankton Organisms, 421. Cumanotus, 313. Cunningham, J. T., A Peculiarly Abnormal Specimen of the Turbot, 44. Current-tube for growing Hydroids, 39. Cuspidaria abbreviata, 372, — curta, 373. — cuspidata, 373. Cuspidella costata, 29. — grandis, 29. Cuthona nana, 230. INDEX. DS, Cyclopterus lumpus. See Lump-fish. — (Humicrotremus) spinosus, See Lump-fish. Cymonomus granulatus, 416. DY Dab from Barents Sea, 94. Decapoda from the Bay of Biscay, 407. — List of Species and Stations, 418. Delesse, on the English Channel, 178. De Morgan, W., On the Species Upogebia stellata and Gebia deltura, 475. Dendronotus arborescens, 237. Dentaliun entalis, 373. — panormitanum (panormum), 378. Desmophyllum eristagalli, 12. — Smithir, 12. Diphasia alata, 31. — ptnaster, 30. — prnnata, 31. — tamarisca, 31. Ditylium Brightwelliz. See Plankton diatoms. Doto coronata, 237. — fragilis, 237. — sp., 387. Dredgings carried out by s.s. Oithona in 1906, 99. E. Kbalia nux, 416. — tuberosa, 416. — tumefacta, 416. Echinus ucutus, rearing, 466. — esculentus, rearing, 466. — miliaris, rearing, 467. Eliot, C., On the Genus Cumanotus, 313. Elwes, Major E. V., Notes on the littoral Polycheta of Torquay, 197, 347. Emarginula fissura, 374. — multistriata, 360, 375. Epizoanthus couchii, 212. — merustatus, 225. — (?) rubicornis, 212. Eryasticus Clouet, 418. Eteone picta, 349. EKudendrium rameum, 23. — ramosum, 23. Kulalia nebulosa, 348. — viridis, 347. EHumida sanguinea, 348. EHupagurus bernhardus, 415. — carneus, 416. — Prideawai, 415. variabilis, 415. Euphausia Miilleri, 191. Eurycope longipes, 196. Eurydice truncata, 195. Eurysyllis paradoxa, 201. Husyllis tubifex, 198. Exogone gemmifera, 197. 1s Facelina drummondi, 236. Filellum serpens, 28. Fishes from the Bay of Biscay, 1. G. Gadus eglefinus. See Haddock. — morrhua. See Cod. Galathea nexa, 415. Galathodes tridentatus, 414. Galvina cingulata, 231. — pieta, 232. — tricolor, 232. Gari costulata, 370. Gastroptychus formosus, 414. Gebia deltura, 475. Geology of the English Channel, 118. Geryon sp., 417. Glycymeris glycymeris, 363. Gobius Jeffrysit, 3. Goniodoris castanea, 239. Gouldia minima, 369. Greenland Shark from the Barents Sea, 96. Grubea clavata, 198. Gymnacanthus tricuspis, 98. Et Haddock from the Barents Sea, 96. Haleciwm sessile, 29. Halibut from the Barents Sea, 95. Haplostylus Normani, 192. Hefford, A. E., Note on a Conger with Abnormal Gonad, 318. — Note on a Hermaphrodite Cod (Gadus morrhua), 315. 516 Hickson, S. J., The Alcyonaria, Antipatharia, and Madreporaria collected by the Hualey from the north side of the Bay of Biscay in August, 1906, 6. Hippoylossoides platessoides. See Long Rough Dab. Hippoglossus vulgaris. Hippolyte varians, 410. Hunt, A. R., Submarine Geology of the English Channel, 179. Hyas coarctatus, 418. Hydrallmania faleata, 32. Hydroids from the Bay of Biscay, 15. — List of species and stations, 16. — method for growing, 37. See Halibut. if Laniva maculosa, 196. Idaliella aspersa, 240, Inachus dorsettensis, 418. — leptochirus, 418. Isidiella elongata, 8. Isopoda from the Bay of Biscay, 189. K. Kemp, Stanley, The Decapoda col- lected by the Huzxley from the north side of the Bay of Biscay, in August, 1906, 407. L. Laemargus nvicrocephalus. See Green- land Shark. Lafoéa dumosa, 25, — fruticosa, var. gracillima, 25. — pinnata, 25. Lamellaria perspicua, 378. Lamellidoris bilamellata, 239. Larvie, rearing of, 464, Laudera borealis, See Plankton dia- toms, Leptomysis gracilis, 198. — sp., 194. Leptonereis Vaillanti, 351. Lictorella halecioides, 26. Lima excavata, 360, 366. — mariont, 359, 367. INDEX. Lima subauriculata, 367. Limopsis aurita, 362. — minuta, 362. Liomesus dalei, 381. Lispognathus Thomsont, 418. List of Governors, Founders, and Members, Ist October, 1908, 340, List of Institutions which have been supplied with specimens of marine animals and plants by the Marine Biological Associa- tion during two years ending 31st May, 1907, 265. List of Publications recording the re- sults of researches carried out under the auspices of the Marine Biological Association of the United Kingdom in their La- boratory at Plymouth or on the North Sea Coast from 1886- 1907, 241. Lomanotus genet, 236. Long Rough Dab from the Barents Sea, 95. Lophogaster typicus, 192. Lophohelia prolifera, 13. Luctnopsis undata, 368. Lump-fish from the Barents Sea, 98. Lyonsia norvegica, 371. M. Mackerel and sunshine, 394. — and Plankton, 269. Madreporaria from the Bay of Biscay, ne Magalia peramata, 350. Magellania craniwm, 392. — septigera, 392. Maurolicus borealis, 1. Meganyctiphanes norvegica, 191. Metridium dianthus, 224. Micronereis variegata, 350. Mollusca from the Bay of Biscay, 359. — List of species and stations, 389. Mihlfeldtia truncata, 393. — Munida bamffica, 415. Munna Boecki, 196. Mysideis insignis, 193. Mysidetes Farrani, 194. Mysidopsis didelphys, 193. INDEX. 517 N. Natica operculata, 369. —- (Lunatia) aldert, 377. — — catena, 377. — — montaqut, 377. — — operculata, 378. — — sordida, 316. Nematoscelis megalops, 191. Nepthys cirrosa, 350. — Hombergit, 349. Nereidae of the French and English coasts of the Channel, key, 357. Nereilepas fucata, 351. Nereis cultrifera, 352. — Dumerilvi, 351. -— wrorata, 352. — pelagica, 351. Nerophis aequoreus, var. exilis, 2. Nitzschia closterium. See Plankton diatoms. — seriata. See Plankton diatoms. Notophyllum foliosum, 349. Nucula nitida, 361. — sulcata, 361. Nudibranchiata from the North Sea, 227. Nyctiphanes Coucht, 191, O. Oculinidae, 13. Odontosyllis ctenostomata, 199. — gibba, 199. Onus biscayensis, 3. — Sp. 3. P: Palliolum similis, 365. — vitreus, 366. Pandalina brevirostris, 410. Pandalus leptocerus, 410, — propinquus, 410. Pandora inaequivalvis, 371. Paralepis sp., 2. Paramblyops rostrata, 198. Parantipathes larix, 10. Paraphellia expansa, 210. Parazoanthus dixont, 213. Pasiphaé princeps, 410. — sivado, 409. Pecten bruét, 359, 364. Periclimenes Korm, 411. Perisiphonia pectinata, 28. Phellia murocincta (Gosse), 47. Phialidiwm, 24. Philocheras bispinosus, var. neglects, 412. — echinulatus, 412. Phycis blenniordes, 2. Phyllodoce lamelligera, 349. — maculata, 348. — Paretti, 349. Phyllodocidae found on the French and English coasts of the Channel, key to Genera and Species, 353. Phyllosoma, 413. Pionosyllis divaricata, 198. — lamelligera, 198. Plaice from the Barents Sea, 74, 502. Plankton and the Mackerel Fishery, 269. — distribution of species, 292. — diatoms, culture of, 423. — — experiments with culture media, 436. — — list of species, 425. — — methods employed, 423. — — mixed cultures, 457. — — notes on particular species, 460. Plesionika martia, 410. Pleurobranchus sp., 387. Pleuronectes imanda. See Dab. — platessa. See Plaice. Plumularia elegantula, 32. — frutescens, 32. — setucea, 32. Polybius Henslowt, 417. Polychaeta of Torquay, 197. Polycheles typhlops, 413. Pomatoceros triqueter, rearing, 468. Pontophilus norvegicus, 413. — spinosus, 413 Portunus holsatus, 416. — pusillus, 417. — tuberculatus, 417. Processa canaliculata, 411. Pseudommea affine, 193. Pseudomuree richard, 360, 384. Pteridiwm Alleni, 4. 518 Publications recording results of re- searches :— Annelids, 257. Botanical, 263. Coelenterates, 259. | Crabs and Lobsters, 251. Crustacea, 255. Echinoderms, 258. Faunistic and General Papers, 261. Fishes, 241, 252. Molluses, 253. Nemertines and Turbellaria, 258. Oysters, 251. Polyzoa, 254. Protochordata, 253. Protozoa, 261. Sponges, 251, 260. Variation, 263. Puncturella noachina, 374. R. Raia radiata. See Starry Ray. Ranella gigantea, 360, 378. Rearing of marine larvee, 464. — methods, 464. — species, 466. Report of the Council, 1906-7, 49; 1907-8, 320 ; 1908-9, 479. Reynell, A., The Brachiopoda collected by the Huzley from the north side of the Bay of Biscay in August, 1906, 392. — The Mollusca collected by the Huzley from the north side of the Bay of Biscay in August, 1906, 359. Lhizosolenia stolterfothrt. diatoms. thodactinia crassicornis, 218. Rhopalomenia aglaopheniae, 361. Rocinela damnoniensis, 195. Rock remains in the bed of the Eng- lish Channel, 99, 118. See Plankton S. Sabellaria alveolata, rearing, 469. | Sacculina careint, rearing, 470. Sagartia coccinea, 208. — luciae, 207. — miniata, 221. INDEX. Sagartia pallida, var. rufa, 222. — sp. 223. — sphyrodeta, 210. — undata, 220. — viduata, 221. Sagartiidae from Plymouth, 207. Salmon, keeping of, 303. Saxicava arctica, 371. Scala clathrus, 379. — richardi, 360, 379. — trevelyana, 379. Scaphander lignarius, 385. Schistomysis ornata, 194. Schizopathes crassa, 11, Schizopoda from the Bay of Biscay, 189. Scopelus (Myctophum) glacialis, 2. Sergestes arcticus, 408. Sertularella gayi, 30. — polyzonias, 30. Sertularia abietina, 24, 28, 31. Striella norvegica, 192. Skeletonema costatum. See diatoms. Solea variegata, 3. Spisula elliptica, 368. Spongicola Koehlert, 408. Starry Ray from the Barents Sea, 97. Start Mackerel Fishery, 282. Stenorhynchus longirostris, 418. Stichopathes spiralis, 10. Stomphia coccinea, 219. Streptotheca thamensis. See Plankton diatoms. Syllidae, key to Genera, 203. — key to Species, 204. Syllis alternosetosa, 199. — krohnit, 200. — prolifera, 199. — spongicola, 199. Synaphobranchus prnnatus, 1. — crocodilus, 2. — (M.), punctatus, 2. Syncoryne eximia, 37. Syndosmya prismatica, 368. Plankton ys Tattersall, W. M., the Schizopoda and Isopoda collected by the Hualey from the north side of the Bay of Biscay in August, 1906, 189 INDEX, 519 Tealia coriacea, 219. Thalassiosira decipiens. See Plankton diatoms. Thracia papyracea, 372. Torellia vestita, 380. Tritonia hombergi, 238. — plebeta, 238. Tritonofusus fusiformis, 383. — gracilis, 381. — turritus, 382. _ — (Siphonorbis) jeffreysianus, 382. — — propinquus, 382. Trophon muricatus, 384. Trypanosyllis celiaca, 201. — zebra, 200. Tubularia sp., 24. Turbot, abnormal specimen of, 45. Turritella communis, 379. Los Upogebia stelluta, 475, Uroptychus Bouviert, 414. — nitidus, var. concolor, 414. — rubrovittatus, 413. Urticina crassicornis, 218. Vi: Venus (Ventricola) casina, 369. — (Timoclea) ovata, 369. Volsella phaseolina, 365. W. Walton, C. L., Actiniz collected by the ss. Huzley in the North Sea during the summer of 1907, 215 — Notes on some Sagartiide and Zoanthide from Plymouth, 207. — Nudibranchiata collected in the North Sea by the ss. Hualey during July and August, 1907, 227. — On Phellia murocincta (Gosse), 47. Western Spring Mackerel Fishery, 270. Worth, R. Hansford, The Dredgings of the Marine Biological Associa- tion (1895-1906), as a Contribu- tion to the Knowledge of the Geology of the English Channel, 118. Worth, R. N., Geology of English Channel, 187. Z. Zeugopterus megastoma, 3. Zoanthide from Plymouth, 207. Zygophylax biarmata, 27. PRINTED BY WILLIAM BRENDON AND SON, LTD. 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