Royal Society. 



227 



at first straight downwards in the middle line, as in Waldheimia, but 

 instead of terminating in a rounded tapering extremity as in that 

 genus, it bends upwards and then curves round to the left side, 

 forming a sort of free caecum in the visceral cavity. My reasons for 

 believing that it is a free caecum are these : — in the first place, no 

 anal aperture can be detected in the mantle cavity, either on the 

 right or left sides, although the small size of the animal allows of 

 its being readily examined uninjured, with considerable magnifying 

 powers. 



Secondly. If the shell be removed without injuring the animal 

 and the visceral cavity be opened from behind by cutting through its 

 walls close to the bulb of the pedicle, it is easy not only to see that 

 the disposition of the extremity of the intestine is such as I have de- 

 scribed it to be, but by gentle manipulation with a needle to convince 

 oneself that it is perfectly unattached. And in connexion with this 

 evidence I may remark, that the tissues of the Brachiopods in general 

 are anything but delicate ; it would be quite impossible for instance 

 to break away the end of the intestine of Lingula from its attach- 

 ments without considerable violence. 



Fig. 2. 



Thirdly. If the extremity of the intestine, either in Rhynchonella 

 or m Waldheimia, be cut off and transferred to a glass plate, it may 



Q2 



