614 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
Spioniform worm; it differs, however, from all the figures 
I have seen of such larvae in the length and narrowness 
of the segments, and the consequent extreme slenderness 
of the larva as a whole. Otherwise it is not unlike the 
larva of Nerine figured by Agassiz in 1867 (see his 
Pl. VI., figs. 40-42) and de Saint-Joseph (1894: p. 69; 
Pl. III., fig. 80). The generic characters (see Mesnil, 
1896, p. 117) of our larva up to the latest stage examined 
are those of J/tcrospio, Mesnil, but as several of these are 
negative its position cannot be regarded as definitely 
established. 
[Nerine.—An early stage of Nerine cirratulus is very 
common at Port Erin, more especially, Mr. Chadwick 
tells me, in the earlier part of the year. I have not yet 
been able to make any detailed observations upon it, 
although I have frequently seen it in the July plankton ; 
and I have not been able to trace its history after the 
loss of the conspicuous vitelline membrane with which 
these early stages are invested. Its identity has been 
determined by Cunningham and Ramage (1887: pp. 
638-9), who recognised this vitellime membrane with its 
characteristic external reticulum of hexagonal meshes to 
be the same as that originally described by Claparede 
(1868: pp. 329-330) surrounding the ova of Nerzne cirra- 
tulus.* These authors describe the segmentation of the 
egg and the development of the Trochophore, which still 
bears the characteristic vitelline membrane (PI. III., fig. 
39, C) through which pass the cilia of the prototroch, 
telotroch, and apical organ. Two pairs of chaetigerous 
parapodia begin to develop before the vitellime membrane 
disappears; the setae of the anterior pair are, as is usual 
*T have found a similar membrane round the eggs of Scolecolepis 
vulgaris ; so these larvae may belong to either of these worms, and 
perhaps to others also. 
