( m ) 
INVERTEBRAL ANIMALS. 
'I. GANGLIATA. — Brain surrounding the gullet, and 
sending out nervous filaments, which in their course ex 
pand into ganglia. 
Class I. Mollusca. — Brain surrounding the gullet^ and send- 
ing out filaments, which separate irregularly. 
Class. II. Annulosa. — Brain surrounding the gullet, and send- 
ing out a knotted filament to the posterior extremity of 
the body. 
II. KADI AT A. — Nervous system obscure, disseminated, 
not appearing in the form of a collar round the gullet, 
nor of a longitudinal cord. 
Although the Radiata appear here as the last of the Invertebral Animals, 
it is my intention to proceed to the consideration of the species which belong 
to the division immediately after the enumeration of the Mollusca. This 
cours ^ I am induced to follow, because an intimate relationship appears ta 
subsist between certain groups of radiated and molluscous animals. Besides, 
by such an arrangement, the whole of the Annulose animals will reniain con^- 
nected, and occupy exclusively the second volume of this work. 
