132 Prof. M‘Intosh’s Notes from the 
spiral in the preparation. A deep notch separates the basal 
segment of the cirrus from the distal. The setigerous region 
forms a short cone with the pointed lamella projecting 
obliquely backward behind it. It is stiffened by three fairly 
stout spines and bears superiorly a group of strong tapering 
winged bristles, the longest being dorsal. Bristles of the 
same kind with shorter and broader tips occur below the 
others. The ventral cirrus does not now project in profile, 
but has merged into the opaque glandular elevation running 
inwards from each foot, a short papilla in two of the suc- 
ceeding feet, however, being present as a rudiment. 
The change from the bifid ventral bristles with their 
indistinct articulation is coincident with the appearance of 
the branchia on the 5th foot, in which the branchial stem 
is remarkably large. 
At the posterior part of the fragment from the ‘ Porcu- 
pine’ the branchial stems are smaller, the dorsal cirri longer 
and more tapered, a straight powerful hook has appeared 
below the inferior bristles, and just above the slight pro- 
jection marking the ventral cirrus is a still more powerful 
curved hook, also bifid and winged, which slopes obliquely 
downward and outward from the spines (Pl. X. fig. 3) and 
the separate hook (Pl. X. fig. 4). 
It is not possible to contrast the entire series of branchiz 
of the two forms, for that procured by the ‘ Porcupine’ had 
only about thirty bristled segments, on the last of which the 
branchie still presented a spiral formation. In the Nea- 
politan specimens Grube gives fifty to fifty-six pairs as the 
number of the branchiz, those examined in the present 
instance having respectively fifty-one, thirty-eight, and fifty, 
several of the last being simple filaments. Grube*, more- 
over, states that the branchize arise on the 5th foot, whereas 
in all examined they began on the 4th foot. Claparéde f, 
again, observes that the occurrence of the branchie on 
the 4th foot (fifth segment) is exceptional, just as their 
absence on the 5th foot is. As Claparéde states, the first 
three feet bear long ventral cirri, the appearance of the 
branchia on the 4th being coincident with the presence of 
* Sitz. d. nat. Sect. Schles. Gesellsch., 20th June, 1877, Sep. Abd. 
walle 
- + Annél. Chét. Nap. p. 123. By the kindness of Mr. Cyril Crossland, 
an opportunity of examining six examples from Naples and others which 
he procured at Zanzibar was afforded. Considerable variation in the 
number of the branchiz, their origin anteriorly, and in the occurrence of 
additional ventral cirri was evident. Mr, Crossland will probably allude 
mote Pe to these features in his account of the “ Annelids of 
Zanzibar. 
