48 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
Cerianthus borealis.* — Dr. D. C. Danielssen first described tins 
species in 1838, but in deference to the opinion of bis colleague the late 
Dr. Koren, he has long considered it as synonymous with G. Llo 2 j(Ui. 
Now, however, having had the opportunities of further studying the 
true C. Llnydii he reverts to his original view as to the distinctness of 
the two species. He now gives a full description of 0. borealis. The 
bilateral symmetry noticed in some other species of this genus is 
apparent also in the northern form, where the bilaterality is internal 
as well as external. 
The ectoderm contains an extraordinarily large number of nema- 
tocysts ; when many are extruded the surface of the body has quite a 
fungoid appearance. In addition to the nematocysts there are a large 
number of unicellular clubshaped mucous glands, the efferent ducts of 
which are of some length. The clear fibrillar area lying beneath the 
ectoderm has been rightly regarded by Profs. 0. and E. Hertwig as a 
nervous structure ; under high powers its median part is seen to consist 
of a large number of nerve-fibrils, from which, on one side, there are 
given off many nerve-fibres ; these form plexuses, and become lost in the 
muscular layer ; on the other side there are ganglionic cells which have 
their broad ends turned towards the layer of nerve-fibrils. The nerve- 
cells have a large nucleus which is surrounded by a rather dark, finely 
granular proto 2 ffasm, and they give off one or more processes which form 
anastomoses, and are lost in the cylinder-cells of the ectoderm. 
Below the nervous apparatus there is a well-develo23ed muscular 
layer, consisting of transverse and longitudinal muscles, the former of 
which are external to, and more delicate than the latter ; the two layers 
cross one another. The layer of connective tissue is very thin and 
homogeneous, and on its inner face there is a thin layer of circular 
musedes which is lined by endothelium. 
There are eight pairs of sep>ta, which are all complete, and of which 
two may be regarded as directive ; between the digestive tract and the 
body-wall there is a large, unpaired, ventral chamber. All the septa 
are formed of a j^retty tliick supporting membrane, and all have mesen- 
terial filaments and gonads connected with them. The sexes are separate, 
and the gonads are quite special in character. 
The female organs form one or more round capsules which are 
separate from, and may be some distance from one another. The capsule 
commences as a protoplasmic thickening, which becomes broader at its 
base ; only one egg is developed in each capsule, and, when it becomes 
free by the bursting of the capsule, it remains between the lamellar 
j3rolongations thereof ; in this position it is, probably, fertilized. The 
testicle is in the form of a snake, and consists of a large number of 
sausage-shajjed emea, which are attached in groups to a membrane of 
connective tissue. Connected with the testicles are many nematocysts, 
which may either have the form of those described by Heider, or may 
be more elongated and have a thicker capsule. The male would appear 
to be smaller than the female, and to have a smaller number of tentacles. 
The digestive tube is cylindrical ; its inner wall is 2 )roduced into 
w^ll-developed longitudinal folds and is marked by two grooves, the 
Bcrgoiis ^Mnsomns Aaisbcrplning for 1S8S (1880) No. 1, 10 pp. (1 pi.). 
