MR. LOVELL REEVE ON TESTACELLA. 153 
On the Structure of the Mantle in Zestacella. 
By Lovett Reeve, Esq., F.L.S. 
[Read April 17, 1862. ] 
AMoné some unpublished drawings of British mollusks obligingly 
placed at my disposal by the Rev. M. J. Berkeley, F.L.S., I have 
been interested in finding a figure of Testacella Maugei with a dif- 
ferent condition of the posterior extremity of the animal to that 
represented in any previous figure or description. THither the 
mantle is produced externally on each side for the lateral embrace 

of the shell, or a pair of lobes is developed for that portion in con- 
nexion with the integuments. Mr. Berkeley informs me that his 
drawing was made from a living specimen given to him by 
Mr. Sowerby about the year 1829, captured, he believes, in a 
garden at Lambeth. “Iam certain,” he adds, “that it is correct ; 
but unfortunately I can find no description.” 
Testacella is a form of much importance in the molluscan series, 
as being the only example of a Slug in which the pulmonary sac is 
situated at the posterior extremity of the animal ; and it is the only 
one of strictly carnivorous habits, burrowing into the ground to a 
depth of two feet and more, and gorging voraciously upon earth- 
worms more than equal to itself in size. The shell, covering the 
pulmonary sac, is the first in the testaceous kingdom to be secreted 
externally, and the first in which an indication is presented of the 
spiral plan of growth which is gradually developed in the shell of 
Daudebardia and Vitrina, and matured in the whorled Heliz. 
Though unknown to Linneus, Zestacella was discovered and 
singularly well observed long before the publication of the 12th 
edition of the ‘Systema Nature.’ In the Mémoires de l’Académie 
. des Sciences of Paris for 1740 is a letter addressed to M. de Réau- 
mur by M. Dugué of Dieppe, from which the following is an 
extract. It has been already cited by De Férussac in his 
‘ Histoire des Mollusques’ (1819), vol. i. p. 89; but it is necessary 
here to repeat it. 
LINN. PROC.—ZOOLOGY, VOL. VI. iM 
