288 BULLID A. 
The greatest variations are in the number of the nervous 
ganglions, the salivary glands, gizzard, and the “ organe exci- 
tateur ;” these we will briefly mention. The central flat white 
retractor of the head and the lateral cesophageal threads are 
nearly similar. In this species the two principal masses of 
the ganglionic cordon consist of three distinct pik lobes on 
each side, instead of two as in its—I had almost said congener, 
B. hydatis ; the two minute buccal and stomachal ganglions 
are nearly similar in shape, position, and in their connection 
by nervous cords with their primary points of departure. 
The very strong gizzard, which is the stomach, is formed of 
three white, testaceous, subtriangular plates, two of which are 
of the same size and shape, the third or key-plate is smaller, 
all bemg pomted at both ends, enclosmg a strong brown 
circular membrane, which receives the cesophagus, from which 
the duodenum departs. The salivary glands, instead of, as in 
B. hydatis, bemg very long and springing from the gizzard, 
are two short corrugated fillets, which origmate on each side 
anterior to the nervous collar, their extremities floating free. 
If M. Cuvier had not determined these appendages to be the 
organs of deglutition, we should have demurred to such views, 
and rather have considered the lateral leaflets around the 
mouth to be the salivary glands, which, being present in the 
three species of the Bullide | have examined, prove that 
they are not accidental markings, but secreting glands; of 
what nature is doubtful. The “organe générateur” or “ ex- 
citateur”’ greatly differs in form in the two genera, which, 
however, can only be considered as a specialty, since its 
function, position, mode of protrusion and retraction, and 
isolation from the testis, are absolutely the same; but in- 
stead of bemg trifid and comparatively short, as in B. hydatis, 
it is, i a moderate-sized animal of B. aperta, at least 3 
inches long, slender, or rather filiform, cylindrical, rolled in 
short folds ito an irregular mass, affixed and in connection 
with the orifice under the right segment of the head, and 
lying, when inactive, under the anterior part of the cavity 
of the gizzard; it can be protruded and withdrawn as the 
finger of a glove can be imverted and again exserted. It 
