348 Sir R. Schomburgk on some new Fossil Shells. 
I found this unique shell near the summit of Bissex Hill, im- 
bedded in siliceous limestone. I am glad that my discovery of 
this new shell has afforded Professor Forbes an opportunity to 
name it after the learned Professor Ehrenberg, who, by his dis- 
covery of a new class of animalcules in the rocks of Barbados, has 
added another claim to our thanks for his indefatigable researches 
into the history of the most minute forms of organic life. 
Mr. Edward Packer of Springfield forwarded to me during 
my stay in Barbados, a specimen of rock consisting of dark gray 
limestone inclosing small quartz pebbles, in which numerous 
shells of the genera Nucula, Lucina, Pleurotoma and Venus were 
so firmly imbedded as to form one mass. According to his de- 
scription, this block lies isolated in the neighbourhood of Spring- 
field, andl do not recollect having met with a similar rock in situ 
during my rambles in the island. I have to regret that the spe- 
cimens of shells which I received from Mr. Packer were mostly 
very imperfect ; this refers chiefly to the Lucina and Pleurotoma. 
One of the species of Nucula was very perfect, which, at my re- 
quest, my friend Professor Forbes has named after Mr. Edward 
Packer, a gentleman who has taken great interest in my researches 
while in Barbados, and offered me many facilities in prosecuting 
them. 
I have consented, not without some hesitation, to the specific 
name of the second species, upon which my kind friend Pro- 
fessor Forbes has insisted. 
Fam. ARC ACE A, Blainv. and Lam. 
Nucula (Led a) Packeri, E. Forbes. (Figs. 2 and 3.) 
** N. testa oblonga, subtumida, transverse striata, longitudinaliter ob- 
lique unisulcata ; latere postico productiore, attenuate, angulato, 
subacuto ; antero rotundato ; margine ventrali simplici, subsinuato ; 
lunula oblongo-lanceolata, carinis elevatis cincta. 
Shell ovate or oblong, rather tumid, produced slightly retrally 
into a subcompressed acutely-angled beak, which is separated 
from the rest of the shell by a shallow furrow ; the other extre- 
mity is rounded. The surface is crossed by very numerous 
transverse striae with sharp intermediate ridges. The beaks are 
prominent. The lunule is well-defined and smooth, and bounded 
by two ridges, one of which is the margin of the upper part of 
the valves. The margins of the shell are smooth. Transverse 
dimension of an inch : beak to frontal margin y^^ of an inch. 
^^This form is allied to several existing tropical and subtropical 
Nuculce, and to some crag forms. 
Nucula Schomburgkii, E. Forbes. (Figs. 4 and 5.) 
N. testa ovato-elliptica, valde insequilaterali, tumida, postice rotun- 
data,antice abrupte truncata, lineis sa?pe divaricatis sculpta; umbo- 
nibus subterminalibus ; lunula lanceolata, marginibus denticulatis. 
