Miscellanea Zoologica. 65 



branches, and in no instance replaced by tentacular cirri. The 

 bristles with which they are garnished are too weak to be of much 

 use as defensive organs. In most of the genera all the feet are si- 

 milar on all the rings, but in some we find those of the anterior 

 portion of the body to diifer from the succeeding ones, and of which 

 the ventral branch at least resembles those feet with crotchets which 

 we meet with so constantly in the order Tubicolae. The soft ap- 

 pendages are subject to much variety in the Ariciadae. The cirri 

 never fail at least on one of the branches of the foot, but common- 

 ly we do not find them on both ; they have sometimes the form of 

 fleshy filaments, more or less delicate, at other times they constitute 

 flattened tonguelets. Branchiae properly so called are in general 

 defective ; sometimes, however, they exist under the form of well- 

 developed lobules fixed to the feet, and in other cases they consist . 

 in a certain number of tentacular filaments, similar to the cirri, and 

 fixed upon the dorsal arch of some of the rings of the anterior part 

 of the body, — a disposition of parts which evidently leads us to that 

 more peculiarly characteristic of the Annelides iubicolce. 



The character of the family may be summed up as follows : 



Feet slightly prominetd in general and of little complexness of 

 structure, sometimes alike throughout, sometimes dissimilar in differ- 

 ent parts of the body, hut never alternately furnished with, and des- 

 titute of certain soft appendages : Branchi^ ?ione or very simple : 

 Head riidimentary : An ten nje and eyes frequently wanting: no 

 Jaws: Proboscis very short and indistinct: no Tentacular 

 CIRRI : In general a single cirrus to each foot, and when a second 

 exists, this is rudimentary* 



Of the four genera which Audouin and Milne-Edwards include 

 in this family, we have two native species of one only ; but it is re- 

 markable that our other species, which as yet are limited to the num- 

 ber of three, constitute two new genera in it very distinct from any 

 hitherto characterized. The fact is an additional illustration of an 

 axiom in natural history, — that all aberrant and osculant groups are 

 not only comparatively few in species, but at the same time these 

 species are so dissimilar among themselves that each, or every two 

 or three of them, will be feund to have characters which are pro- 

 perly generical. 



It may be useful to give the characters of all the genera hitherto 

 proposed, for as the British species are probably more numerous than 

 has been ascertained, so it is not unprobable we may have a repre- 

 sentative of each genus. 



* Translated, but not always closely, from Audouin and M.-Edwards, ut sup. cit. 



VOL,. II. NO. 7* E 



