24 BULLETIN OF THE 



the stomach by two ducts on each side, of which the anterior were the 

 larger. They did not extend over or cover the sides of the intestine. 



The heart is extremely small and difficult to find. It is situated lower 

 down than in most species and between and hidden by the hepatic lobules. 

 It is nearly spherical. No accessory pulsatile vesicles were found after 

 close scrutiny. 



The ovaries differ in appearance from those of Waldhehnia and Tercbra- 

 tulina. They hang like a frill or puckered ribbon-like lamina from the pallial 

 membranes, and form a simple loop on each side of each valve. Those of 

 the haemal (dorsal) valve were most developed. The ends of the loops 

 extended into the great pallial sinuses. The rounded granules which 

 studded the frills were of two kinds. Those at or near the extreme edge 

 were of a pellucid deep brown hue, while those closer to the pallial mem- 

 branes were mostly of a pale yellowish color and quite opaque. The ovi- 

 ducts are very inconspicuous and not easily found. They are situated in 

 the usual position, but exhibit only a very few short folds, and the exter- 

 nal opening directly in the midst of them, instead of being at the end of a 

 rather long duct, as in other forms. There are only two of them. They 

 do not appear to be attached to the intestine or mesenteries, but lie flatly 

 upon the parietes. 



The pallial sinuses are comparatively insignificant in this species, being 

 very narrow, almost linear, channels with few branches. A few spicule 

 were observed in some of them. The margin of the mantle is perfectly 

 plain, without seta?, and adhering closely to the shell. Yet the circumpal- 

 lial muscular band is much broader than usual and strongly marked. 

 W lien torn from the shell, the ca?cal prolongations of the mantle were 

 beautifully shown. They were often bifurcate and occasionally had three 

 or even four branches. 



The punctate structure of the shell was very coarse. Even the crura 

 and laminae of the apophyses were punctate. 



The nervous system was not traced out, but the oesophageal ganglia 

 presented no special peculiarities. 



The border of the mantle appeared to be ciliated. The peduncle, so 

 wide and short as to resemble a mere muscular disk, was strongly at- 

 tached to the shell by the peduncular muscle, beside which a broad tendi- 

 nous band appeared to pass entirely across, in front of the dorsal adjusters 

 (posterior retractors of Owen), giving an additional solidity and firmness 

 to the attachments of the peduncle. The extremities of all the muscles 

 were very much enlarged and thickened, while their median portions were 

 slender and 'tendinous. No striated fibres were observed. 



