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THE PLEISTOCENE SITE OF IPSWICH.
street-diggings are made, and sometimes fossils of those old Glacial days have been unearthed in even Westgate and Carr streets. I t is not, perhaps, too m u c h to suggest that the presence of this terrace, high above even the winter floods and yet within convenient reach of the river, was a main reason why our earlyhistoric people began to erect a town upon the spot. T h e wide piain, traversed by good water and well sheltered northerly, constitutes an ideal home : its soil was dry and well open to the south, the basic water-supply was ample and access to the sea free, though sufficiently distant for protection from piratical rovers. River Orwell must be thanked for all these benefits as, through countless ages, it has cut its course adown t h e Valley and, in the later stages of so gigantic a task, washed out the broad terrace that is the town's backbone to-day.
ON PLUMAGE OF THE BY CHESTER G .
DOUGHTY,
GANNET. B.A.
THE fresblv disembodied skin of a Gannet (Sula bassana, L.) without head or legs, with only half a wing but a complete white tail, showing it to be a mature bird, was discovered on t h e shore at Gorleston on 8 December 1932, though not much of a prize to the hardened old beach-combing Naturalist. But later I found the other half of the wing about fifty yards away and, noticing its white primary ; saw it must be taken home for further investigation. A few days afterwards I came upon the other wing some quarter-mile f r o m the original d e b r i s : and thus assembled very useful material, exhibiting three peculiarities in the plumage : (i) It does not moult its feathers in pairs, i.e. the corresponding feathers on the two sides of the body ; (ii) T h e new feathers of a pair, when produced, do not always agree with each other in markings and c o l o u r ; and (iii) It has a distinct tendency to produce white feathers, where they should be dark. Attention ought to be called to these facts, because most ornithologists have few or no opportunities of handling Gannets in t h e flesh. I must point out that the juvenile is an entirely dark bird specklcd with w h i t e ; and that the mature one, after numerous moults, is an entirely white bird with the exception of its ten long primaries, which are very dark brown, and of its head and neck, which are pale b u f f : these remarks apply to the plumage only and not the soft parts. T h e effect of (i) therefore is sometimes rather curious. It appears that an old all-dark secondary quill may be replaced by a new all-white quill at a Single moult, and consequently a new white secondary in one wing may be paired by an old dark secondary in the other ; and, when it is
ON P L U M A G E OF T H E
GANNET.
159
remembered that there are thirty secondaries to the wing, the effect of such irregularity in moulting, aggravated by (ii), may produce one wing very differently coloured from the other. However, as my half wing had only four secondaries attached, it is with the primaries that we are mainly concerned. i. In the right wing the first long primary was six inches in the web (10f), the sixth three inches (8) and the eighth three ; in the left wing the second primary was 10J inches ( 1 1 ) : the measurement in brackets gives the length in inches of the feather in the web when fully grown. We have, therefore, three sprouting feathers in the right wing against one, and that nearly full-grown. in the left. T h e remaining primaries in each wing were full-grown, but the fourth in the right like the fifth and seventh in the left appeared to be new feathers. All the coverts of the sprouting and apparently new primaries seemed new feathers but fully grown, except in the case of the sixth and eighth primaries in the right wing : the covert of the former was U inches (4) and of the latter 2 inches (3-|). ii. T h e ninth and tenth long primaries illustrate this point, but are dealt with under iii. T h e covert of the ninth long primary was apparently an old feather in each w i n g ; in the right one it was all dark except a small patch of white at the base, and mainly on the inner but partly on the outer web ; in the left one this feather was pure white. In the right wing the first secondary was possibly a new feather; it was entirely dark, with a paler patch at base on inner web ; in the left this feather was undoubtedly new and was mainly dark with a rather darker patch at base on inner web than in" the case of its fellow, but with a clear-cut white wedge at top of inner web that did not quite reach the lateral margin. Of the four feathers forming the bastard wing, the fourth was apparently new in the right wing, and the first and second and fourth equally apparently in the lett. The first feather in the right was pure white; the first and apparently newer feather in the left was, curiously, entirely • The third feather in the right was dark, but whitish on inner web at base ; the third in the left was the same, but this an 3 n ^ l r 0 W m a r g i n a l s t r i P o f P u r e w h i t e on inner web near with each t ^ m a i n i n g f e a t h e r s o f t h e bastard wing corresponded both i!'! 1C n i ? u h a n d t e n t h l o n g P r i m a r i e s > normally dark, were t C n t h P r i m a r y o f right wing had a very narrow and l T snort stnp 0 f dark brown running along the quill on inner g a b ° u t a n i n c h f r o m base of web and continued by a h'n left Win"'?! \ h e q u i U t 0 a b o u t o n e i n c h f r o m its a Pex. In much 1 I P a t c h o c c u r r e d o n t h e ninth primary and was at one n T 8 ^ j I ? a m l y o n o u t e r w e b > reaching to outer margin q U l U W a s d a r k w h e r e h a h u t t e d upon the dark nat h . the nniii f ! ? t h r e n c e n g h t U P t o i t s extreme apex. Otherwise 4 ms ol these four primaries were white. T h e other primaries
160
ON PLUMAGE OF THE GANNET.
had the usual dark quills, with white bases. For some unknown reason the ninth primary of the right wing, and tenth of the left, were extremely abraded. It seems to me most curious that the first secondaries should have been entirely or mainly dark, when the ninth and tenth primaries were white. All the other secondaries on the whole and half wings, and those attached to the skin, were pure white.
ENTOMOLOGICAL CAPTURES DUNWICH.
ABOUT
BY K. G. BLAIR, D.SC., F.E.S., F.Z.S. THE end of one of the dryest summers of recent years was not particularly promising for an entomological holiday, but it was hoped that the extensive marshes of the Dunwich district would have suffered last September as little as anywhere from the long period of drought. This hope was not altogether realised; nevertheless, a few captures of especial interest were made. T h e dykes in these marshes held little in the way of brackishwater beetles, but Ochthebius marinus, Pyk., was plentiful in some places. One specimen of Hydaticus seminiger, DeG. (NEW to Suffolk), was found alive in the edge of the sea just east of Minsmere marshes, but the beetle could not be found in those marshes themselves. On sandy slopes at the foot of cliffs there Microglossa nidicola, Fair., had fallen in plenty, from nests of Sand-martins above them, on to a large clump of Milfoil, along with Olibrus corticalis, Pz., Rhinoncus castor, F. and Trachyploeus scabriculus, L., which were mostly under Sorrel, while odd specimens of Strophosomus faber, Hbst., Apion laevicolle, Kby. (NEW to Suffolk), Lindes ciliaris, Schm. (Tr. Suff. Nat. Soc. 1930, p. 123), Anthicus florahs, L. and Sericoderns lateralis, Gylwere'also taken. With them was Sibinia signata, Gyl. = primita. Hb., confirming a somewhat doubtful Suffolk record of 1S9 [already later confirmed by examples taken in June at Barton Mills (E. A. Elliott); in April at roots of Marram-grass on K e s s i n g l a n d sandhills (Bedwell) ; and beaten from oak in a Sandy fir-wood at Brandon (Morley).—Ed.]. A gap in the cliff-top one windy day produced a host of small beetles, sitting in a pocket on the face of the cliff; these were mainly Staphylinidae: Atheta spp., Tachyusa atra, Grav., Tachyporus spp., Quedius semiaeneus, Ste. and boops, Grav., Gabrius trossulus, Nd., etc., together with Mecinuspyraster, Hbst., Anthicus antherinus, L., a few Longitarsus and numbers of smaß Hymenoptera. T h e prize of this remarkable assembly is a Single example of Aleochara inconspicua, Aube (NEW to Suffolk), thus placing firmly on the British List, and adding to Beare s oi 1930, a species whose sole claim to inclusion has hitherto been