88 ANNELIDA. 



vertebres." For the generic characters I have also 

 been indebted to Messrs. Andonin and M.-Edwards's 

 " Littoral de la France/' to M. Moquin-Tandon's 

 " Monographic des Hirudinees," and to the nume- 

 rous papers of Dr. George Johnston in various 

 zoological periodicals. In the enumeration of 

 British species I have principally depended on the 

 " Index to the British Annelides '' of the last- 

 named gentleman, a work which in small space 

 exhibits the concentrated result of immense re- 

 search and labour, — the additions made to the Irish 

 Fauna by Mr. W. Thompson, — the contributions 

 of Mr. Goodsir, and Professor Allman, — and my 

 own personal researches. It is understood that 

 Dr. Johnston is about to bring out a work on the 

 British Annelida, which is anxiously looked for 

 to dispel the obscurity and confusion which con- 

 fessedly rest on this, perhaps more than on any 

 other department of our native zoology. 



Annelida. 



Body lengthened, soft, divided into numerous 

 ring-like segments; without jointed limbs; with 

 an orifice at each extremity of the alimentary 

 canal; blood generally red, circulating in a closed 

 system of arteries and veins ; skin not clothed with 

 cilia, except on the breathing organs. Distinct 

 sexes. 



Without bristles, or foot-like warts. Loco- 

 motion performed by means of sucking disks Apoda. 



With bristles serving for locomotion, and 

 generally carried on foot-like warts, which 

 are furnished with various appendages . . Chcetopoda. 



