294 Dr. W.C. M‘Intosh on the Boring of certain Annelids. 
(Ersted and Mr. Lankester) has clearly made out another 
European species; for I consider Leuckart’s Leucodore mu- 
ticum* a somewhat inaccurately described L. céiliatus, John- 
ston. ‘The possession of only two eyes, and the fact that the 
great hooks occur on the “ sixth” segment of the body, and 
are three-toothed, characterize the L. nasutus of M. de Qua- 
trefages. The author states that the anal segment terminates 
in a flattened cup, which permits the Annelid to attach itself 
to solid bodies ; and his figure shows no split in the margin. 
If thé latter arrangement is correct, then the previous cha- 
racters may hold. It is also but fair to remark that speci- 
mens occur at St. Andrews with two eyes, and even with one 
only, and that the anterior pair in all, being on a lower level, 
are less easily seen from the dorsum than the posterior. The 
same may be said of ZL. audax and its circular cup. More- 
over, as the latter assumes somewhat altered appearances in 
those whose tails are regenerating, some caution is needed in 
basing specific differences thereon. His L. Fabric? rests, as 
a species, upon characters that require further elucidation ; 
and the remarks on L. ciliata are based on Dr. Johnston’s 
description; and hence the author is misled as to the structure 
of the hooks of the sixth segment (fifth of the body), which 
really, as already mentioned, have a secondary spur or process. 
L. dubia is also founded on insufficient data. Lastly, there 
can be little doubt that the Polydora cornuta described by 
M. Claparédet, and given by M. de Quatrefages as the type of 
a new genus, is nothing more than L. ciliata. The want of 
scientific accuracy in the figures of the genus in the ‘ Annelés’ 
renders identification difficult. 
EXPLANATION OF THE PLATES, 
PuatTe XVIII. 
Fig. 1. Leucodore ciliata, Johnst.; enlarged under a lens. 
Fig. 2. Great hooks of the fifth segment of the body: a, as usually seen 
in the separated and perfect organ under pressure; 6, a more 
complete view, as obtained in the living animal or in a favourable 
spirit preparation. x 700 diameters. 
Fig. 3. Spear-tipped bristles accompanying the former. x 700 diams. 
Fig. 4. Hooks of the posterior region of the body: a, pressed between 
glasses; 6, seen in front, so as to exhibit both wings. x 700 
diams. 
Fig. 5. Front and side view of two of the bristles of the same species. 
x 700 diams. 
Fig. 6, Caudal segment and its cup. x 210 diams. 
PLATE XIX. 
Fig. 1. Tubes erected by Leucodore at the apertures of its tunnel. The 
* “Zur Kenntniss der Fauna von Island,” Archiv fiir Naturges. 1849, 
p. 200, Taf. iii. fig. 12. 
+ Recherches Anat. sur les Annélides, Turb. &c, 1861, p. 47, et op. ect. 
