222 H. L. Han-kins — Buccal Plates in Echinocorys. 



bone now figured (Fig. 4). It is of a brown colour and much 

 mineralized. I was told that the gravel came fi'om Bedfordshire, 

 possibly from the Biddenham pits, where Mr. Wyatt obtained many 

 flint implements. It shows at one end cut marks on both surfaces. 

 Dr. Duckworth informs me that it is from the lower end of the 

 posterior part of the left humerus of a large ungulate, probably 

 Bos taurus, and he has pointed out the position of the fragment 

 (Fig. 5), showing that the hollow, which so conveniently fits the fore- 

 finger and causes the thing to lend itself so readily to the hand, as 

 Sir Joseph Prestwich remarked to me, is a part of the natural 

 configuration of the bone. It does not seem probable that a fragment 

 of tliat shape should splinter off such a bone unless it was broken 

 intentionally. The article seems just suitable to be used spoon- 

 fashion, and it would serve well for scraping the marrow out of 

 a split bone. If that was its purpose, I think it is a rare instance 

 of finding a Palaeolithic implement intended for personal convenience. 



VI. — The Plates of the Buccal Membrane in Echinocorys. 



By Herbert L. Hawkins, M.Sc, F.G.S., Lecturer in Geology, University 



College, Beading. 



A SPECIMEN of Echinocorys showing the plates of the peristome 

 was exhibited at the Conversazione of the Geologists' Association 

 in 1910 by Mr. W. H. Bennett, and has, through the courtesy of that 

 gentleman, been forwarded to me for detailed examination. In view 

 of the perfect preservation of the peristomial structures, and the 

 extreme rarity of their discovery, I have thought it advisable to 

 publish the following short description. A comparison is made 

 between the sti'ucture shown in this specimen and that described by 

 Loven in the young stages of Echinocardium. 



Description of the Test. The broken test, of which only the 

 anterior part of the base is preserved, was found by ^Jr. Bennett on 

 beach reefs 100 yards east of the steps at 'Black Rock', Brighton, 

 in the upper part of the zone of Marsupites. The form would seem, 

 judging by the fragment remaining, to have been a characteristic 

 example of the variety of Echinocorys vulgaris called pyramidatus by 

 English workers, this variety being almost restricted to the Marsupite- 

 zone. The base is almost flat, and the sides are curved up from it 

 through rather more than a right angle, making the edge of the 

 adoral surface coincident with the greatest width of the test. 



The flatness of the base is interrupted around the peristome, which is 

 situated in a considerable hollow. The portion of the test between 

 the anterior margin and the peristome is inclined sharply towards the 

 interior of the Echinoid, and on the other side of the peristome the 

 plastron rapidly regains the ambital level. Part of the concavity 

 thus formed contains the large podial pores and their attendant 

 tubercles, the deepest part alone being occupied by the peristome. 



The Shape of the Peristome. The peristome is a roughly elliptical 

 aperture, whose greatest width (transverse measurement) is 6'1 mm. 

 This diameter is towards the posterior part of the opening. The 

 greatest length (antero-posterior measurement) is 4-4 mm,, this being 



