Historical 13 



the orders. The orders were thus deiined : (1) Nereideae — feet with 

 retractile suhulate chaetae but without crotchets, a distinct head with 

 eyes and feelers, and a protrusiblc proboscis almost always armed 

 with jaws; (2) Serpuleae — feet with retractile subulate chaetae and 

 crotchets, head without eyes or feelers, proboscis not armed with 

 jaws ; (3) Lumbricinae — without projecting feet and with chaetae 

 rarely retractile, head without eyes or feelers, and without jaws ; 

 (4) Hirudineae — without locomotor chaetae, characterised by the 

 presence of a sucker at each extremity and by having eyes. The 

 families were arranged in the orders thus : — 



I. With chaetae for locomotion. 



1. Order Nereideae. Families — Aphroditae, Nereides, Eunicae, Am- 



phinomae. 



2. Order Serpuleae. 



(1) Gills none or few ; if present situated on the anterior segments 



of the body ; feet of several kinds. 



Families — Amphiti'itae, Maldaniae. 



(2) Gills numerous, not on the anterior segments of the body ; feet 



of one kind. 



Family — Telethusae. 



3. Order Lumbricinae. Families — Echiuri, Lumbrioi. 



II. "Without chaetae. 



4. Order Hirudineae. Family — Hirudines. 



This is the first list of Annelids published from which all 

 Mollusca are excluded.^ It is also of interest from our special point 

 of view, as the family Telethusae was formed for the reception of the 

 single genus Arenicola. 



Savigny's classification is more natural than any of its pre- 

 decessors, as it is based not on a single feature, but on a group 

 of characters. ]More than forty years afterwards Prof. Elders con- 

 sidered it to Ije so excellent that he adopted it, with only a slight 

 change, in his monograph on " Die Borstenwiirmer," and the 

 classification in use at the present day is based on an extension of 

 the principles of Savigny's system. In addition to his fundamental 

 improvement of the classification of Annelids, Savigny also carefully 

 delimited the known genera and founded more than a score of new 

 ones, most of which remain valid. 



Latreille- adopted ("uvicr's classification in a modified form, 



' baviguy observed that Dciitalinm was not an Ainielid. and he also 

 excluded L'Ai'rosoir and Siliquana. 



• Families nat. Regne Anim., Paris (1825). 



