BULLACE TREE BULL <E A. 



643 



edge sharp and smooth ; it sometimes attains a con- 

 siderable size, and is very prettily clouded with red 

 or ash-coloured marking's, broad pink, and black 

 bands or fine lines. The type of the genus B. lignosn 

 is of a straw colour, and elegantly marked with hair- 

 like lines running spirally ; and the animal possesses 

 a very singularly formed testaceous substance within 

 its body, not noticed by Lamarck, and familiarly 

 called by English collectors the gizzard. The animal 

 inhabiting the bulla has an oblong oval body, thick 

 and obtuse at the extremities, which are formed of 

 two parts, the posterior entirely covered by the shell, 

 with the edges of the mantle thickened in front, but 

 particularly so, backward on the left side, where it 

 forms a lobe bordering the aperture ; the anterior 

 more considerable, provided on the right and left 

 with a swimming enlargement of the foo.t ; the head 

 indistinct, with two inconsiderable labial appendages, 

 two sessile eyes very distinct, and behind these a pair 

 of tentacules prolonged on the lateral parts of the 

 neck. 



De Blainville places the bulla in his second class 

 Paracephaloi>hora, third order Monopleurobranchiata, 

 fourth family Accra, and he arranges the species in 

 the following order : first, such species as are closely 

 convoluted, with the spire visible and projecting exter- 

 nally, the aperture very narrow backward, as in the 

 B. jonkaria, here figured, and forming the genus 



B. jonkaria. 



B. np!ii5tre. 



Aplustre of some autnors ; secondly, the species that 

 are completely convoluted, rotund, the spire very dis- 

 tinct, but not projecting, with a sort of thickened band 

 at the anterior part of the columella edge, as in the 

 B. aplustre, here figured ; thirdly, such species as are 

 of a thicker substance, very completely convolved, 

 the turns of the spire scarcely visible in an umbilicus 

 more or less deep, projecting inwardly, as B. hydatis 

 in the figure ; fourthly, the species that are thin, ven- 

 tricose, the turns of the spire externally visible, bul 

 not projecting, with a suture, as if channelled, anc 

 without any thickened band on the columella side 

 as in the Bulla naucuin ; fifthly, the species ex- 

 tremely thin, much involved, the turns of the spire 

 distinct within and without, the suture deep, angular 



which are much more involved than the others, and 

 tfithoutthe spire being visible internally or externally, 

 as in the B. lignaria, figured below ; and lastly, the inter - 



B. frapilis. 



and channelled the whole or part of its length as in 

 the B. frayilis, here figured ; sixthly, the species in 



B. lignaria. 



nal species, which are very thin, convoluted, with a 

 slight commencement of becoming rolled at the origin 

 of the left lip, as in the B. aperta, here figured, con- 

 stinting Lamarck's genus Bullcea. 



B. aperta. 



De Blainville has thus united Lamarck's genus 

 bullcea to the bullse, the propriety of which we do not 

 admit, as the reasons which led to their separation 

 remain unshaken. In the first place, the genus bulla 

 is never an internal mollusc, and can altogether re- 

 cede within its covering. The animal is also attached 

 to its shell by a muscle, while, on the contrary, the 

 bullcea is totally enveloped in the mantle of the 

 animal, not visible externally, nor attached to the 

 shell by any muscle ; to which may be added, that the 

 thickness, colouring matter, and more regular convo- 

 lutions of the bulla, seem to mark it most distinctly 

 as a separate genus. It is true they are both said to 

 be carnivorous, and to swallow bivalve molluscs, but 

 the evidence of that circumstance appears to want 

 confirmation. 



These shells are found in all climates, but the most 

 beautifully coloured are from the warmer latitudes. 

 Lamarck enumerates eleven recent species, and about 

 ten fossil have been described by different authors. 



The derivation of the name of this genus is obvi- 

 ously from a bubble, which their inflated appearance 

 and slight texture greatly resembles. 



BULLACE TREE is the Primus imititia of 

 Linnasus. This is a useful fruit tree, and often found 

 wild in the hedges about old farm houses. Why it 

 should be called insititia (grafted) is not explained, 

 as it propagates itself by suckers as easily as its 

 congener, the sloe. Indeed, the bullace seems to be 

 only an intermediate variety between the sloe and 

 the damson plum, being much better and larger than 

 the first, though not so large nor so good as the last. 

 A bullace pie is a standing dish at the harvest-home 

 supper in the south of England ; only, it requires 

 rather more sugar than the housewife is always 

 willing to allow. 



BULLFINCH. See PYRRHULA. 



BULLCEA (Lamarck). This mollusc has been 



separated from the genus Bulla, for reasons which 



are stated in the description given under that name. 



The tvpe of the genus and the only species known 



3 B 2 



