IIG bloomer: anatomy of pharella and tagelus. 



The anterior oesophagael division (Figs. 2 and 3, A.Oe. St.) is long and 

 narrow and divided from the posterior oesophagael one by a muscular 

 ridge passing round the stomach. 



The posterior oesophagael division (Figs. 2 and 3, P. Oe. St.) lies 

 between the anterior oesophagael and the pyloric divisions. At its posterior 

 end is the central division (Fig. 2, CD.) bordered by a muscular ridge 

 (Fig. 2, C.D.R.). 



The dorsal side of this ridge is more developed and represents the 

 muscular papilla of Solen (Fig. 2, M.P.). It separates the central 

 from the cardiac division (Figs. 2 and 3, C. St.). Continuous with it is 

 also a ridge (Fig. 2, Oe. C.R.) which divides the posterior oesophagael from 

 the cardiac division. In the anterior part this muscular tissue extends 

 right across, thus completely separating these two divisions. 



The pyloric division (Figs. 2 and 3, P. St.) is large and occupies the 

 whole of the posterior portion of the stomach. On the right side is a 

 muscular ridge (Fig. 3, P.D.R.) running from the posterior oesophagael 

 ridge nearly round this pyloric division. The ventral portion of the 

 pyloric division narrows and continues as the caecum of the crystalline 

 style (Figs. 1, 2, and 3, C.C). The caecum is very long and large. It 

 first passes ventrally, then curving, extends a considerable distance along 

 the pedal cavity. 



The intestine (Figs. 1 and 3, In.) leaves the ventral surface of the left 

 anterior part of the pyloric division, the typhlosole commences, and the 

 intestine proceeds first a little anteriorly, curves, and goes ventrally 

 running just anterior to the caecum of the crystalUne style, from which 

 it is separated by a row of transverse muscles. It then turns anteriorly 

 and forms a number of large folds, in the last of which the typhlosole 

 disappears and the intestine proceeds posteriorly, passing over the 

 right side of the caecum, then going dorsally, passes in a large loop over 

 the posterior part of the pyloric division, and turning posteriorly continues 

 as the rectum (Fig. I, R.). It is shortly afterwards encircled by the 

 ventricle (Fig. I, F.), then passes over the posterior adductor muscle into 

 the exhalent siphonal chamber, terminating in a bi-lobed anus (Fig. I, A.). 



The liver (Fig. I, L.) lies laterally, ventrally, and partly dorsally 

 around the stomach. The large bile duct enters on the ventral surface of 

 the posterior oesophagael division and the smaller bile duct into the central 

 division. 



Circulatory System. 



Apparently closely resembles that of Solen. 



As regards the gill structure, Dr. Ridewood '" states :— " In the 

 five species of Solen examined the lamellte are heterorhabdic and plicate, 

 the plication being shallower in Solen orientalis than in the others. 

 The numbers of filaments in a plica are nearly the same in the two demi- 



1. Phil. Trans. Roy. Soc, 1903(ser. B), vol. ]9o, pp 147-:2s4. 



