449 



It will be seen that neither in the Polyzoa nor Brachiopods are 

 there any true molluscan characters, nothing homologous with the 

 foot, the shell gland or odontophore. The Brachiopods should in 

 our opinion be, perhaps, united with the Polyzoa and form a group 

 lower but sub-parallel with the Annelides. The Brachiopods, from 

 the facts afforded by Morse and others, have neither such a nervous 

 system or respiratory or circulating organs, or an annulated body, 

 as would warrant their union with the Chsetopods. He has fully 

 proved that they are a synthetic type, combining the features of 

 different groups of worms, and this fact apparently forbids their 

 being regarded as a group of Chsetopods. Looking at the subject 

 from an evolutional point of view, we should be inclined to regard 

 the Brachiopods and Polyzoa as derived from common low vermian 

 ancestors, while the Chaetopod worms probably sprang indepen- 

 dently from a higher ancestry. 



To sum up, the Brachiopods pass through 



1. A Morula state. 



2. A free swimming, ciliated Gastrula condition, formed by in- 

 vagination of the ectoderm. 



3. Free swimming larval annulate Cephulala stage, combining 

 the characters of the larva of Nareda and of Tornaria the larva 

 of Balanoglossus. 



