ANNELIDES. 
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segmenta omnia pinnis superioribus destituta ; and Aeolosoma ; setis 
capillaribus praedita. Under the Chcetogaster Oersted arranges Nais 
diaphana, Gruith. ; and in Aeolosoma the A. Ehrenhergii, Oerst., which 
may be Aeol. decorum, Ehrb. et Aeol. Hemprichii, Ehrb. ? 
Eathke (Neueste Sclir. der naturf. Ges. in Danzig. B. iii. 
Heft 4, 1842, p. 56) has published a very minute description 
of the Ampliitrite auricoma, with beautiful plates. 
Rathke observed this worm alive on the Norwegian coast. The mouth 
is without jaws, and beset on both sides with a tuft of fifteen tentacles, 
capable of being much elongated and shortened, and two red blood- 
vessels shine through them. These tentacles secrete a glutinous slime, 
and are covered on their upper surface with very vibratile cilia. Close 
upon the notched fold of skin which envelopes the tuft of tentacles, there 
is found on the vertex, on each side, a transverse row of thick golden 
yellow bristles, which are ]3ut in motion by several bundles of muscles. 
The margin between the occiput and upper side of the head, is edged by 
an indented fold of skin, which runs out anteriorly to a pretty long and 
thick cirrus ; the post- occipital segment has, on each side, a somewhat 
smaller cirrus, and the second and third rings of the body have a golden 
yellow branchia, the leaves of which glitter strongly. On the inner side 
of the tuft of bristles, and the leaf-like projections found upon them, is 
remarked, on each of the other segments of the body, a round and rough 
protuberance ; four such protuberances are situated on the mesial line, on 
the abdominal side of the first four body rings ; these rough portions of 
skin probably serve for defending the animal, when it slips out of the 
tube in which it is concealed. The anal part of the body consists of two 
halves, of which the one resembles a heart, furnished with indented 
lateral margins, while the other smaller half represents a moderately 
thick oval leaf. The anus is placed where those two parts join together. 
From the contents of the alimentary canal, Rathke concludes, that 
this animal is nourished only by the slime of the sea. As neither eggs 
nor seminal fluid were found in the cavity of the body, it is probable, 
that it possesses separated sexual organs. How the eggs and seminal 
mass get out of the bod37-, is not clear, and Rathke supposes, that for this 
purpose, openings are placed on the sides of the body, near the different 
bundles of bristles. A quadri-partite glandular mass, situated on the 
first and second rings of the body, on the abdominal side, with an opening 
externally in the first ring, probably serves for the secretion of a 
cement, which the worm uses in making its arenaceous tube. 
We have also, by the same author (op. cit. p. 84), the description 
of the hitherto little known Siphouostoma plumosum (Amphitrltc 
327 
