424 Dr. Johnston on the British Aphroditacea. 



XLVIII. — Miscellanea Zoologica. By George Johnston, 

 M.D., Fellow of the Royal College of Surgeons of Edin- 

 burgh. With Plates XXL, XXII., and XXIII.* 



VI. The British Ai'HRODiTACEiE. 

 Class Annelides. Order Errantes. 



Character. Head distinct, antenniferous : proboscis in 

 general with four jaws in adjunct pairs : feet well developed, 

 not uniform in structure, for some are furnished with a supe- 

 rior cirrus and usually with branchiae, but without scales; while 

 others, usually squamous, are neither branchial nor cirriferous, 

 and these alternate, for a definite space, along the sides : 

 branchiae sometimes obsolete, always rudimentary and con- 

 cealed, in the form of crests or tubercles situated on the upper 

 part of the dorsal branch of the foot above the cirrus. 



General Observations-^. 



Of the Annelides furnished with a distinct head, there are 

 some which are flattish and of an oval form ; others are slender, 

 cylindraceous and almost filiform. The former constitute the 

 genus Aphrodita of Linneeus, the latter his Nereis, but these 

 genera embrace animals too dissimilar to be so closely asso- 

 ciated. Bruguiere, who saw this, began the reform and led 

 the w ay to a more natural classification : he divided the Aphro- 

 dita into two groups, to one of which he preserved the Lin- 

 naean name, and he called the other Amphinome. For the time 

 this was considered a sufficient subdivision ; and Bruguiere 

 was followed implicitly, in the first instance by Cuvier and 

 Lamarck ; but when Savigny, with richer materials and a 

 deeper knowledge of them, had raised the Aphrodita to the 

 rank of a family with its several subordinate genera, his ar- 

 rangement and nomenclature were readily adopted by La- 

 marck, Latreille, and Blainville, and, we may add, are now im- 

 disputed. 



The AphroditacecB possess all the characters of the order to 

 which they belong : the head is distinct, they have eyes, an- 

 tennae, a fleshy retractile proboscis, and feet to every ring of 



* [These Plates will be found in the Supplement published with the pre- 

 sent Number. — Edit.] 



■\ Translated, but not literally, from Andouin and M. Edwards, 



