348 Sir R. Schoraburgk 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, and 1 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- 

 fessoi* Forbes has insisted. 



Fam. ARCACEA, Blainv. and Lam.. 

 Nucula (Leda) Packeri, E. Forbes. (Figs. 2 and 3.) 

 ** N. testa oblonga, subtumida, transverse striata, longitudinaliter ob- 

 lique unisulcata ; latere postico productiore, attenuate, angulato, 

 subacute ; antero rotundato ; margine ventrali simplici, subsinuato ; 

 lunula oblongo-Ianceolata, 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 -f-^ of an inch : beak to frontal margin j^q of an inch. 



"This form is allied to several existing tropical and subtropical 

 Nucula, and to some crag forms. 



Nucula Schomburgkii, E. Forbes. (Figs. 4 and 5.) 

 *' N. testa ovato-elliptica, valde inaequilaterali, tumida, postice rotun- 

 data,antice abrupte truncata, lineis ssepe divaricatis sculpta; umbo- 

 nibus subterminalibus ; lunula lanceolata, marginibus denticulatis. 



