NARRATIVE OF THE CRUISE. 
620 
‘■'Amongst the pelagic forms tlie most conspicuous are the Alciopidse, a group which 
seldom comes under the eye of the British zoologist, and which are so delicate that great 
care is necessary in preserving them. One of the best memoirs on these Annelids has 
recently been published by B. GreefF, and most of the forms collected by the Challenger 
agree generally in structure with those described by him. Two or three new forms 
however occur, one ( Alciope cintarctica ) frequenting the surface of the Antarctic Ocean in 
company with Cleodorci, and the others in the warmer waters near Honolulu. The first 
mentioned has its head formed almost wholly by its two great eyes, which project promi- 
nently outward in front of the constricted neck. Moreover, the cornese of these eyes are 
invisible from the dorsum, being so placed that they look outward and downward. The 
anterior feet have the form of large globular processes. Another [Alciope quaclrioculata) 
is characterised by the presence of four eyes, two occupying almost the entire central 
area of the head, with the corneas directed outward, while two others, somewhat rudimen- 
tary, look outward, forward, and slightly downward. The third form ( Nauphanta ) with 
massive lateral lamellae, somewhat resembles Notophyllum, one of the Phyllodocidae, 
the head however bearing two great eyes with the corneas directed outward. 
“ The presence of large eyes has hitherto 
been associated with the Alciopidae, but the 
explorations of the Challenger have made us 
acquainted with a similar condition in a closely 
allied group, viz., the Phyllodocidae. This new 
form [Genetyllis oculata), instead of being a 
surface form, frequents a depth of 500 fathoms 
near the Pacific entrance of the Celebes Sea, 
south of Mindanao. In the form of its body 
and the size of its eyes it resembles an Alciope. 
The eyes (fig. 214) occupy most of the head, 
only a small triangular space being left 
anteriorly and posteriorly. The large trans- 
parent corneas look outward, downward, and forward, and are surrounded by a belt of 
brownish pigment. The minute anatomy of these organs, as well as those of the Alciopidae, 
has been carefully investigated by Dr. Marcus Gunn, one of the oculists of the Moorfields 
Hospital, London, and he finds that the head is composed of little more than the eyes 
and agreat median nerve-mass, with which the retinae of both eyes are continuous. It 
is interesting that the Ioida- forms (sexual buds) of the Syllidae with large eyes are also 
pelagic, occurring near the surface of the ocean amongst Sagittce, Copepods, Nauplii, Zooeae, 
and the minute free young and ova of fishes. 
“ In viewing the collection of Annelida brought home by the Challenger as a series of 
families, it is found that while the Euphrosynidae present no new forms, the Amphinomidae 
Fig. 214. — Horizontalsection through both eyes of Genetyllis 
oculata, showing their relation to the cerebral ganglion 
(somewhat diagrammatic), a, Junction of the anterior part 
of the sclerotic, — the oval spaces are blood-vessels cut 
across ; b, the cornea ; c, finely granular, clear, structure- 
less material, probably of the nature of vitreous; d, pigment- 
layer of retina; e, the large cerebral ganglion. 
