Eliminius modestus

240

PREHISTORIC MAMMALIA

Machaerodus sp. Sabre toothed Tiger. Fossils of this extinct family are extremely rare in this country so it cannot be expected many would be found in East Anglia. Teeth referable to Machaerodus are recorded from Red Crag. An incomplete canine tooth is in the Ipswich Museum from the Norwich Crag at Covehithe. This was originally referred to Homotherium because it appeared to lack the serrations on the posterior edge which exhibits marked signs of wear. Close examination, however, reveals a row of minute dark marks which correspond to the spaces between the serrations of the anterior edge. These undoubtedly indicate the former presence of serrations on both edges as may be seen on the perfectly preserved tooth from the Cromer Forest Bed now in the British Museum.

Machaerodus has serrations on both edges of the canines, Homotherium has them on the anterior edge only and a third genus has none at all. This family had its origins back in the Eocene epoch (F. E. Beddard, " M A M M A L I A ", Cambridge Natural History, 1 9 0 2 , p. 4 0 2 ) and O . Schmit, " M A M M A L I A ", International Science series, 1894, p. 276), thought it became extinct during the Miocene epoch which lasted about 20 million years. Lydekker " Catalogue of British Fossil Mammals " 1894, lists remains of unknown date (possibly derived), from Kent's Cavern, Torquay.

T h e latter may be of more recent date than the Forest Bed, but the evidence indicates the survival of at least one genus into the Pleistocene (first-interglacial of about half a million years ago).

ELMINIUS MODESTUS (Darwin) from the Stour Estuary by

J.

COLLINS

the collection of fossil material from the Inter-glacial deposits on the North bank of the River Stour at Stutton on 9th July, 1959, large numbers of the recent barnacle Elminius modestus (Darwin) were observed on pebbles exposed at low tide.

A search was made to see if any specimens could be found attached to other objects and one dead Shore-crab, (Carcinides maenas L.,) was found with four individuals on its carapace. Also on the carapace were three specimens of Baianus improvisus (Darwin).

T h e basal length of the largest specimen ofE. modestus was 6.5 mm. while the largest specimen of B. improvisus, which was seen to be overlapping an individual of E. modestus, was 5.4 mm.

DĂœRING

ELIMINUS MODESTUS

241

Primarily an Australian barnacle, E. modestus was first recorded in British waters (Chichester Harbour) by Bishop in 1947, and it is thought that it was introduced sometime during the war on the hulls of ships, whose passage from Australia had been speeded up.

In 1947/ 48 it was recorded from different parts of the SufTolk coast and since then it has spread to many parts of our coast-line.

(Crisp 1958).

While small, E. modestus may easily be recognised by its shell being composed of only four compartments instead of six.

REFERENCES

Bishop, M. W. H. 1947. Establishment of an immigrant barnacle in British waters. Nature, Lond. Vol. 159 p. 501.

Crisp, D. J. 1958. The spread of Eliminius modestus (Darwin) in North-weat Europe. J. mar. biol. Assoc.U.K. (37) 483 - 520.

Darwin, C. 1854. A Monograph on the sub-class Cirripedia.

Sessile Barnacles. Ray Soc., Lond.

FEEDING

HABITS OF NOCTULE (.NYCTALUS NOCTULA)

by THE

BATS

EARL OF CRANBROOK

are common at Great Glemham and in summer are seen Aying in numbers on the park in front of Great Glemham House. In July and August of 1959 they had not been seen in their usual numbers on that area and Mr. Axell's obssrvations (page 271) led me to look at a similar but much larger dump on the edge of Framlingham Aerodrome about | mile away. This dump was also alive with crickets and at dusk many noctules appeared Aying low over the dump and were seen to take crickets in Aight on a number of occasions. My experience is that on the ground crickets are not easy to catch, running and jumping to avoid capture at the approach of a possible predator. On the wing in the air however they are poor Ayers, Ay in a straight line and continue to Ay in a straight line if chased, making no attempt to take evasive action. Their senses in Aight must be as acute on the ground and this apparent insensibility to the presence of danger while in the air is presumably due to the fact that they are physically NOCTULES