226 



Royal Society. 



me no small surprise, and I have taken very great pains to satisfy 

 myself of the accuracy of my conclusion ; but notwithstanding the 

 strong prejudice to the contrary, to which the known relations of the 

 anal aperture in Lingula gave rise, repeated observation has inva- 

 riably confirmed it. 



Professor Owen's statement is, that in Rhynchonella {Terebratula) 

 psittacea " the intestine inclines to the right side and makes a slight 

 bend forwards before perforating the circumscribing membrane in 

 order to terminate between the mantle lobes on that side." — On the 

 Anatomy of the Brachiopoda, p. 152. 



1 find, on the contrary (figs. 1 and 2), that the intestine passes 



Fig. 1. 



Fig. 1. Rhynchonella psittacea, viewed in profile; the lobes of the mantle and 

 the pedicle being omitted. 



Fig. 2. The same viewed from behind, the pedicle having been cut away. The 

 left half of the body and the liver are omitted. 



a. mouth ; b. oesophagus ; c. stomach and liver ; d. intestine ; e. imperforate 

 rectum ; /. mesentery ; g. gastro-parietal bands ; h. ilio-parietal bands ; i. superior 

 ' heart ' ; k. inferior ' heart ' ; /. genital bands ; m. openings of pallial sinuses ; 

 ». pyriform vesicle ; o. sac at the base of the arm ; p. ganglion ; q. adductors. 



