KUNGL. SV. VET. AKADEMIENS HANDLINGAR. BAND 39. N:o l. 53 
But also in other respects KOREN and DANIELSSEN overlooked matters of im- 
portance. Thus, for instance, they de not allude to the opening on the dorsal sur- 
face behind the tentacles, which is surrounded by small lips and opens into a small 
pit, which had been previously noticed by KEFERSTEIN and EHLERS (1861): in Si- 
punceulus nudus (Figs. 138, 139, 150. s 0). By means of this pit the nerve-centre comes 
into elose contact with the surrounding medium, and it may certainly be looked upon 
as a kind of organ of sens. Probably the pit in question represents a ciliated fossa, 
corresponding to those on the sides of the head of the Nemerteans or to the "”cilia- 
ted pad" or "pads', present in most of the Phascolosoma forms. | 
With regard to the "glandular formations' KOREN and DANIELSSEN write: 
<At the anal aperture there appear on the rectum 2 small gland shaped organs, and 
immediately below these a little divertiecle'". For my own part, I am doubtful whether 
they really are glands. The truth is, that just at the place where they have been 
observed, two strong muscular ligaments are seen combining the rectum with the 
body-wall. But, as far as I have been able to observe, these ligaments are always 
covered by an envelop of small bladders, which at first sight resembles a ""deposit” 
of coagulated corpuscles of the body-cavity. After a careful examination of the very 
badly preserved material I must, however, confess that the "deposit" presents the 
aspect of a racemous compound gland, a very singular thing in these forms of in- 
vertebrates. Further investigations may throw light upon the matter. The diver- 
tiele is very inconsiderable in size (Fig. 150. d.). 
As the longitudinal canals of the body-wall, which run between the longitu- 
dinal musecle-bundles, the alimentary canal etc., I have nothing of importance 
to add to the account given by the two Norwegian investigators. Unfortunately 
circumstances have compelled me to abstain from more detailed researches into these 
particulars. Considering that the whole organisation of this animal is of a very high 
interest, a renewed careful examination is highly desirable. In order to complete 
the statements of KOREN and DANIELSSEN with regard to the longitudinal canals of 
the body, I refer merely to Figs. 146, 147 and 150, and to the explanation of them. 
Lastly, with regard to the nerve-system, KOREN and DANIELSSEN write: "The 
nervous cord, which in the posterior rounded extremity of the body forms a bulbous 
swelling, goes forward, sending out on both sides a number of branches, and winds 
itself at last round the oesophagus, forming there the usual nerve-ring'”. I must con- 
fess that I do not understand the meaning of the words last quoted. By referring 
to my figures (138 and 150), the reader will perceive that the nervous ring is narrow 
and very prolonged, so that the true ventral nerve-cord takes its origin far back, 
and that the lateral branches, which are given off from that part of the nerve-cord 
which belongs to the proboscis, run free for a long space within the body-cavity, 
and that they also divide before entering the body-wall, where they form the most 
beautiful plexus. 
1 Zool. Beiträge gesammelt im Winter 1859/60 in Neapel und Messina. Leipzig 1861. 
E. Sv. Vet. Akad. Handl. Band 39. N:o 1. I 
