120 bloomer: anatomy of pharella and tagelus. 



(Fig. 5, In.) is only partly separated from the caecum and appears as an 

 irregular groove on the side of the latter. Near ths distal end of the 

 caecum the intestinal walls unite, thus completely enclosing it. The 

 intestine (Fig. 4, In.) returns along the dorsal surface, and becoming free 

 passes to the posterior part of the proximal portion of the foot, and makes 

 a large number of folds (Fig. 4, F.In.) at and over the posterior division, 

 then turning posteriorly continues as the rectum (Fig. 4. R.). It passes 

 round the posterior adductor muscle, and on the posterio-ventral surface 

 ends at the anus (Fig. 4, A.). The liver (Fig. 4, L.) surrounds the anterior 

 portion of the stomach with a considerable part lying underneath it. 

 The large bile duct enters on the ventral surface of the anterior division, 

 just in front of the intestine, and the smaller bile duct into the central 

 division. 



Circulatory System. 



The circulatory system generally resembles that of S. strig Hiatus. 

 As regards the structure of the gills. Dr. Ride wood remarks '^' : 

 " The gills of the three species of Solenocurtus examined agree toler- 

 ably closely in their general structure. The lamellae are highly plicate, 

 the plicae being flattened antero-posteriorly so as to resemble the leaves 

 of a book. The number of filaments in a plica are about 30 in the outer 

 and 40 in the inner demibranch in Solenocurtus strujillatus, and Soleno- 

 curtus {Tagelus) rufus, while in Solenocurtus (Macha) philippinarum the 

 numbers are about 24 and 30. In Solenocurtus rufus all the interlamellar 

 septa rise high up the demibranch but in the other two species alternate 

 septa are of small vertical extent. Solenocurtus rufus also has in the 

 apex of the plica, a blood tube which is not noticeable in the other two." 



Nervous System. 



The nervous system is very similar to that of S. strigillatus, the chief 

 differences being in T. rufus, a smaller number of branches of the posterior 

 pallial nerves and more particularly the absence of the large ones crossing 

 the siphonal retractor muscles. 



Reference Letters. 



4. Op. cit. 



