ANNELIDS FROM THE N.E. PACIFIC. 247 
parapodial cirri of Jicronereis exhibit the same structure so 
far as can be seen from the material available, which was not 
preserved for cytological examination.) 
With regard to the four pairs of tentacular cirri, Claparéde 
stated that he was unable to decide whether some of these 
should not be regarded as tentacles (‘‘ Kopf-ftihler”). As has 
been indicated by McIntosh, these should probably all be 
regarded as cirri corresponding to the four pairs present in other 
nereids. 
We are now in a position to compare MMicronereis morpho- 
logically with other nereids. According to the above revised 
views as to the head-parts and parapodia, it would seem that 
we have in Micronereis a surviving descendant of the primitive 
ancestral type from which the successful nereid line of to-day has 
arisen. 
The most characteristic features of this well-marked family 
are to be found in the peculiar, lobed, biramous parapodia, the 
well-developed prostomium or cephalic lobe with its palps and 
tentacles, the four pairs of peristomial cirri, and the armature 
of the proboscis with conical papille. All these features can be 
directly derived from the Micronereis-type. This I shall now 
endeavour to explain :— 
Micronereis as a@ True Nereid.—The right of this genus to 
be included in the family Nereide is upheld by the following 
characters: the body-region bears on each segment a pair of 
deeply cleft biramous parapodia, each ramus supported by a 
Text-figure 9. 
— 
= ca 
é SS = 
Micronereis variegata. 10th parapodium, X 45. 
lance-like aciculum and giving rise to a series of compound 
homogomph spinigerous sete of typical nereid form, and bearing 
a subulate cirrus on its external* surface. The first two 
pairs of parapodia are incomplete, the dorsal division (noto- 
podium) with its spine and seta-bundle being entirely absent. 
Thirdly, the head-region bears dorsally two pairs of well- 
developed eyes situated at the angles of a trapezium, and 
* T. e., respectively dorsal and ventral in the noto- and neuro-podium. 
