170 Dr. Johnston on the Irish Annelides. 



armed with compound bristles, — the superior tubercle being 

 always situated between the dorsal and second papillae, and 

 the inferior tubercle between this and the ventral papillae. On 

 these particulars I will endeavour to define the British spe- 

 cies before me ; and I trust that, with the designs which il- 

 lustrate the specific characters, the student will now be able 

 to determine, with comparative ease and certainty, such of 

 them as he may meet with in his researches. 



Genus Nereis. 



("Nereis, Cuv. Reg. Anim. iii. 20). Aud, 8f M. Edw. Litt. de la France, 

 ii. 181. — Lycoris, (Savigny,) Lam, Anim. s. Vert. v. 311. 2de edit. v. 

 548.) For the character of the genus see Annals of Nat. History, iii. 

 p. 289. 



* Feet homologous. 



1. N. brevimanusj post-occipital segment not longer than 

 the second ; tentacular cirri once and a half or twice its dia- 

 meter ; jaws with 8 serratures, the apices unarmed ; feet 

 homologous, the branchial papillae subequal, the inferior coa- 

 lescent with the setigerous tubercle on the posterior feet ; cirri 

 very]^short, not reaching the apex of their lobes ; setigerous 

 tubercles well-developed, the bristles smooth. 



Fig. 1. 



Nereis hrevimanus. 



Hah. Coast of Ayrshire, Mr. P. W. Maclagan. 



Worm about 3 inches long, and about the size of an earth- 

 worm of the same length. Head narrow : eyes very distinct : 

 antennae not projecting beyond the palpi : proboscis rough- 

 ened as usual with black horny spinules : the serratures of the 

 jaws coarse but not reaching to the point, which is plain. 

 Segments about 88, narrowed posteriorly, the anal one ter- 

 minated with rather long styles. The inferior branchial lobe 

 becomes smaller as we trace the feet backwards, and near the 



