12 LEPADES. 



DISTRIBUTIO METHODIC A. 

 LEPADES. 



Animalia mollia, affixa ; capite oculisque nullis ; corpore subresupinato, 

 inarticulate), in tegmine amplo, quasi in pallio involuto, tentaculis 

 numerosis cirratis, multiarticulatis, per paria dispositis, desuper in- 

 structo, per orificium superius exeuntibus ; ore subinfero, non 

 prominulo, maxillis lateralibus dentatis linguaque rudimentaria 

 munito. Systema nervosa ganglionorum seriem symmetricein 

 format. Circulatio corde indistincto vasculisque confecta ; respiratio 

 brancbiis pectinatis, duabus aut pluribus, saepissime absconditis, 

 ad basem tentaculorura appositis. 



Testa vel sessilis, vel pedunculo flexili, tendineo, elevata, partibus 

 pluribus composita, modo mobilibus, distantibus, modo conferru- 

 minatis, pallio aut tegmine intiis vestitis. 



Few animals throughout the system of nature present a more singular 

 anomaly in their organization than the Lepades ; they may be said to 

 partake of the characters of three distinct divisions of Invertebrata, the 

 Crustacea, the Annelides and the Mollusca, but are not immediately 

 referable to either. Like the Crustacea they are provided with nume- 

 rous articulated tentacular cirri and other organs, but the body is not 

 articulated, and is moreover entirely destitute of head or eyes : as in the 

 Annelides the body offers an indication of transverse wrinkles, and as in 

 the Mollusca it is enveloped in a tunic or mantle, which produces certain 

 pieces of solid calcareous shell, differing entirely in composition and 

 structure from that of the Crustacea. 



In considering the relative value of this anomalous union of characters 



