40 ANNELIDA POLYCHAETA. 



In A. Claparedi the branchiae are generally more deve- 

 loped as in A. marina, and the first pair of them, though 

 not so large as those of the middle body-segments, are 

 rather large. The branchiae consist of about 18 branchial 

 leafs, situated in the same plane, and connected at their 

 base by a common membrane; each branchial leaf bears 

 on its sides about six branched filaments , of which the 

 inferior are somewhat longer than those at the tip. The 

 ventral bristles (fig. 1) can easely be distinguished from those 

 of A. marina ; they are characterized by an obvious en- 

 largement , serrated at its convex side beneath the hook- 

 like curved tip (fig. la). In A. marina the ventral brist- 

 les are not quite smooth as commonly described by the 

 authors , but they show at the convex side one or more 

 faint serrations (figs. 3 and 4). The dorsal bristles resem- 

 ble those of A. marina, which have been accurately descri- 

 bed and figured by Grube. Their distal portion is furnished 

 along one side of the shaft with numerous short hairs, giving 

 it a finely serrated appearance, whereas the other side is 

 provided with a narrow membrane. Probably this membrane 

 is composed of hairs , lying densely near each other , for 

 examined with a high power it shows faint, transverse 

 lines and a serrulated edge (fig. 5). 



Levinsen gives the following characteristics of A. Cla- 

 paredi: » branchiae, which are connected at their base only 

 by a very short membrane, stretched, with 10 pair of 

 branches; dorsal bristles with very faintly developed hairs, 

 ventral bristles with more acutely pointed , somewhat se- 

 parated tip. The branchiae , as stated afterward , agreeing 

 in their structure with those of Pteroseolex antillensü, above 

 referred to." Though this description does not quite agree 

 with my own observations, nevertheless I hesitated to pro- 

 pose another name. Perhaps he confounded with A. Cla- 

 paredi individuals of the following species, which possesses 

 branchiae , agreeing in structure with those of A. antillensis. 



A. cristutu Stimpson (figs. 6 — 11). — Proceed. Boston 



Notes from tb.e Leyden M useum , Vol. XI. 



