BLOOMEE: on species of SILIQUA and ESSL9. 195 



(Figs. 2 and 3, Oe.St.). The latter is neither deep nor long, but very 

 wide. The central division (Fig. 2, CD.) is deep, and bordered by 

 a muscular ridge. Dorsally the oesophageal and central divisions are 

 completely separated from the cardiac division (Figs. 2 and 3, C.St.) 

 by a muscular wall (t'igs. 2 and 3, Oe.C.R.) sti'etching laterally across 

 the stomach. The posterior portion of this divisional wall, which also 

 forms the dorsal limit of the central division, is very strongly 

 developed. The cardiac division projects anteriorly a little over the 

 oesophagus and extends posteriorly to the pyloric division (Figs. 2 

 and 3, F.St.), from which it is likewise separated by a muscular ridge 

 (Fig. 2, M.R.C.). The pyloric division (Figs. 2 and 3, P.St.) is 

 large, and irregular in shape. On the ventral side, at the posterior 

 end, it continues as the caecum of the crystalline style (Figs. 1, 2, 

 and 3, C. C). The latter is also large, of considerable length, and 

 passes with a curve towards the dorsal surface of the pedal cavity. 



The intestine (Fig. 1, In.) leaves the stomach anteriorly to the 

 ctecum of the crystalline style. After forming, in and on the liver, 

 a number of loops, it passes to the distal end of the caecum and 

 returns some distance along its ventral surface, when, becoming free, 

 it proceeds to the dorsal surface of the pyloric division. Turning 

 posteriorly, it continues as the rectum, is soon encircled by the 

 ventricle, and, passing over the posterior adductor muscle to the 

 exhalent chamber, terminates at the bilobed anus. 



The liver is large, and covers the stomach, with the exception of the 

 posterior end. The mass of it, however, lies ventrally to the stomach. 



Nervous System. 



The cerebi'O-pleural ganglia are wide apart, anterior, although near 

 to the retractor pedis anterior muscles, and are joined by a commissure 

 passing in front of the mouth. Each ganglion apparently gives rise 

 anteriorly to only one nerve, which innervates the anterior adductor 

 muscle and the mantle-lobes. Posteriorly each ganglion is connected 

 with a pedal ganglion, but it is not possible to locate the exact 

 position of the latter in the specimen examined. Each cerebro-pleural 

 ganglion is also joined with one of the viscero-parietal ganglia by 

 a connective running between the viscera and lateral integument, then 

 underneath the bifurcated parts of the retractor pedis posterior muscle 

 to the ganglion. 



The viscero parietal ganglia are situated between the bifurcations 

 of the retractor pedis posterior muscle Each ganglion gives off 

 laterally a branchial nerve, and only one posterior nerve, viz. the 

 posterior pallial nerve. It innervates the posterior adductor muscle, 

 the siphon, and the mantle-lobes. 



Gills. 

 A transverse section, cut horizontally to the axis of the demi-branch 

 (Fig. 4), shows it to belong to the type homorhabdic, also to be non- 

 jilicate, and consequently not presentiug any differentiation of the 

 tilainents. The interlamellar junctions are not regularly situated, the 

 number of filaments between them varying considerably and ranging 

 from 10 to 24. 



