muscular bundles, running dorso-ventrally. The animals feed on Alcyonaria, the remains of 

 which are easily discernible and found in great numbers in the intestine. 



When examining fig. 70, a reconstruction of the anterior part of another specimen, a great 

 difference is noticed from fig. 63. Yet there is also a correspondence between the two, considering 

 that in fig. 70 the state of the digestive canal is due to the walls of the mouth-cavity being 

 stretched and the pharyn.\ being contracted, whilst in fig. 63 on the contrary the walls of the 

 mouth-cavity are contracted, the pharynx being stretched. If we suppose in fig. 63 the walls 

 of the mouth-cavity are stretched, then the pharynx takes a different position : it is invaginated 

 into the mouth-cavity; thus the ventral wall of the pharynx is drawn ventrally and the radula 

 and salivary glands change ihcir position. The digestive organs in the anterior region of the 

 Ijody are very movable, which explains the important differences in the transverse sections. 

 The structure of the radula and salivary glands however offers decided points of similarity. 



The rectum with its stronglv ciliated wall gradualh' merges into the cloaca. The latter 

 is a vertically placed slit, which widens proximally and gradually takes the shape of a heart ; 

 the dorsal ])art (a) passes into the rectum, the ventral and smaller ])art {/>) into the precloacal 

 organ (fig. 79). 



Fig. 78 shows a reconstruction of the uro-genital organs, out of transverse sections of 

 a young animal. In full-grown specimens the pericardium is so large as often to cover the 

 other organs; it is for this reason that I chose a young animal. Figs. 79 — 82 give schematic 

 sections through the posterior end of another specimen, comparable with the lines AB — G // 

 of fig. 78." The one thing worth noticing are the appendages of the cloaca-ducts; they are 

 round pouches, connected with the cloaca-ducts, where these bend, by narrow tubes. In mature 

 specimens they are filled with spermatozoa. The wall consists of cylindrical epithelium, which max 

 become cubical when the vesicles are filled with spermatozoa and therefore dilated. The number 

 varies considerably : very young specimens have none at all, whereas I counted in one mature 

 specimen on both sides about 20. The specimen of fig. yS is so young that the cloaca-ducts 

 are still separated; yet it has already the receptacula seminis. A similar arrangement also 

 obtains in Proneomenia australis (Tiiielf. 9). 



The heart greatly resembles that of Proneomenia Weberi. Here again both atria are 

 already formed before the coalescence of the pericardial offsets ; in one specimen they are even 

 already entirely closed (fig. 81). After the atria have united, the double character is .still 

 recognisable. The ventricle is again an invagination of the dorsal jjericardial wall and in some 

 specimens a double communication is discernible between atrium and ventricle. 



Regarding the nervous system the only thing to be mentioned is, that though both 

 lateral nerve-stems are connected by a commissure with the two ventral ones in the distal 

 bod\-region, yet the commissure between both lateral stems (ganglion posterius superius), above 

 the rectum is wanting. 



The question arises, whether we have not to do with Proneomenia australis, of which 

 TiiiKLE gives a short description (9). The length-index of the latter is 18; the cirrhi of the 

 mouth-cavity are arranged in bundles; remains of Alcyonaria are found in the intestine; the 

 receptacula seminis are present : all of them points of resemblance. Points of difference are : 



SIBOGA-EXPEDITIF. XI.VII. 3 



