ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
789 
spongicola Gr., Hesione sicula D. Ch., Arenicola grubii Clap., and 
Hermella alveolata Lam. The author makes use of the term sensory 
nerve termination instead of any one more precise, because he believes 
that, in the present state of our knowledge, it is rash to speak too 
strictly. In the first place it is clear that the sensory nerves terminate 
in contact with an epithelium and not in the subjacent layers. The 
termination is generally to be found in the appendages with which the 
surface of the animal’s body is provided, such as the tentacles, palps, cirri, 
or elytra, but it is sometimes on the body-wall at spots where there are no 
appendages. The nerve-fibres may come into relation with cells of the 
type of the olfactory rods of Vertebrates, in a number of cases the nerves 
enter into relation with ciliated cells, and in yet others it is impossible 
to distinguish the epithelial cells in which the sensory nerves end from 
the cylindrical covering elements. The author comes to the conclusion 
that it is not possible to characterize an organ as sensory by the nature 
alone of the epithelial cells which bound it ; it is only by attentive study, 
by the examination of structure, and by the relations of the various 
elements which enter into its constitution that one can be certain if it 
belongs to the organs of the life of relation. 
Study of Tubificidse.* — Miss Harriet Kandolpli has been able to 
make an investigation into the structure of Seenuris velutina , which 
was first described by Grube, and has since been the object of some 
doubts. She confirms the accuracy of Grube’s description, but as she 
found an allied species which also presents points of distinction from 
all other Tubificidse, she purposes to place them both in the new genus 
EmbolocepJialus ; the name is based on the power possessed by both 
species of withdrawing or invaginating the head. It is proposed to call 
the new species E. plicatus. The chief generic characters appear to be 
the presence of a covering in which foreign bodies are deposited, and of 
non-retractile sensory organs arranged in rings on each segment, as well 
as the retractility of the head and the absence of eyes. Specific distinc- 
tions are to be found in the arrangement of the sensory papillae, and of the 
nephridia, in the presence or absence of a proboscis, and in the form, 
number, and arrangement of the setae. The great interest of the genus 
lies in its exhibiting affinities to the Naidomorpha and points of distinc- 
tion from other Tubificidae, and the affinities to the one group or the 
other appear to be almost impartially shared by the two species. 
The genus is also interesting as an example of the strongly coloured in- 
habitants of deep water. 
Aquatic Oligochaetous Worms. | — Mr. F. E. Beddard commences 
with some notes on a species of Dero, the vascular system of w T hich is 
remarkable from the fact that there are six pairs of contractile lateral 
vessels in segments vi.-xi. Pristina longiseta has been observed in 
England, and the author thinks that the observations of Prof. A. G. 
Bourne show that the two genera Pristina and Naidium can no longer 
be distinguished. There are some observations on the incompletely 
known Acolosoma niveum, which by its colourless integument and two 
kinds of set© offers a transition to the Naidomorpha. It seems probable 
* Vierteljahrschr. Naturf. Gesell. Zurich, xxxvii. (1892) pp. 145-7. 
f Proc. Zool, Soc. Lond., 1892, pp. 349-61 (2 figs.). 
