238 Prof. M'Intosh'.s Xotes from the 



Ouc of tlic latest contributions is a liistological paper on 

 Owenia by Ziircheri*, avIio enters into t])o minute structure 

 of tlie nuisck's, showinpj that the lonjj^ spindle-shaped niusele- 

 crlls have a spiral character (formerly noted by Ogneff), 

 M hich in transverse section give them a barred aspect. A 

 (' rcular muscular coat occurs only at the second dissepiment 

 and forward to the branchial lobes. This also has spindle- 

 shaped cells witli_ nuclei. lie combats Gilson's view, as 

 Ogneff had previously done, that there is no line of demar- 

 cation between the muscular coat and the peritoneum, that 

 the nuclei are rare in the mnscnlar fibres and by-and-by 

 vanish, and that it is impossible to distinguish the nuclei of 

 the muscles and those of the glaiul-cells. He points out 

 that the peritoneal nuclei are generally rounded, whereas the 

 nuclei of tlie muscles are oval and flattened, with the long 

 axis in the line of the muscle-cell. He goes somewhat fully 

 into the histology of the circulatory system (his hremocoel), 

 the main trunk consistijig of a dorsal vessel cariying the 

 blood forward and a ventral trunk carrying it backward. 

 The dorsal forms a blood-sinus round the gut to the second 

 septum, then breaks up into a network over the canal, the 

 trunks fusing at the first septum and sending forward a 

 scries of vessels to the branchise, the returning vessels 

 uniting to form the ventral trunk below the gut. The walls 

 of the vessels have a fine epithelial coat and a delicate circular 

 muscular layer with minute nuclei in their spindle-shaped 

 cell-. The author also objects to Gibson's statement that 

 no special constrictor to the alimentary canal occurs at the 

 septa, and points out that at the third septum an efficient 

 constrictor apparatus exi^ts both for the canal and the blood- 

 sinus, the muscular apparatus showing the large muscle-cells 

 at the outer ends of the fibres. Posteriorly also the 

 filimcntary canal is mouihform from its constrictions. He 

 is inclined to think that Drasehe's bladder-like tissue on the 

 ventral mesentery is part of the reproductive apparatus. 

 The ampullae on the ventral blocrd-vessel, which Drasche 

 observed to be rythmically contractile, are confined to the 

 genital region of the body, and bear the reproductive 

 elements on their outer surfaces, and, though they have 

 muscular walls, ZUrcher would attach more importance to 

 their nutritive capacity. The red blood contains rounded 

 or lenticular corpuscles with nuclei, and some corpuscles 

 undergo mitosis. He found them in the ampullse and less 



* Jexiai«clie Zeitschr. far Natwrwi.'^?. Bd.xlv. pp. 181-220. pis, xv.-xx. 



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