310 ON THE CLASSES OF THE 



peduncle, afford very powerful arguments for adopting an 

 opinion originally Lamarck's, and for supposing that the 

 Cirripeda are connected with some of these, such as the 

 Lingula anatina. But on advancing a little deeper into 

 this examination, and finding the total dissimilarity of con- 

 struction which exists between these two tribes of animals, 

 we acquire the conviction of the relation between them 

 being only one of analogy; since the limpet shape of a 

 Balanus might afford as good a reason for asserting its 

 affinity to a Patella, as the peduncle of a Lingula can pos- 

 sibly give for its connexion with Pentelasmis. M. Du- 

 meril indeed has placed the Cirripeda in the order of 

 Brachiopoda, with which he terminates the Mollusca; 

 but this could only have been because the true Brachio- 

 poda have near the mouth two long ciliated arms, or rather 

 organs of respiration, terminating in a spiral when at rest, 

 together with the abovementioned tendinous cord which 

 sustains the shell. 



Not only however are the internal organizations and 

 nervous systems of a Lingula and Pentelasmis totally dis- 

 similar, but the respiratory arms of the former are nowise 

 articulated ; so that, as M. Lamarck observes, u Les Bra- 

 chiopodes ne tiennent nullement aux Cirrhipedes par les ca- 

 racteres de leur organization; leur coquille memeria aucun 

 rapport avec celle des Cirrhipedes, quelque variee que soil 

 celle de ces demiers." Y\ r e cannot therefore pass from the 

 Anmilosa to the Mollusca by means of the Cirripeda, un- 

 less the most fanciful comparisons be employed in order 

 to effect our object ; comparisons indeed that are all, more 

 or less, founded on relations of analogy, but which are 

 perhaps unconnected with any principle of affinity. It is 

 however clear that the Cirripedes are on the limits of be- 



