ON A REMARKABLE SYLL1S-BUD. 13 



of a glandular appearance ; though in some of them I could 

 recognize a very distinct oval nucleus , the limits of the 

 cells could not always be distinguished. Between the ex- 

 ternal and the internal layer of cells a hyaline membrane 

 is to be found. The internal cavity of the pouch is filled 

 up with a mass of small granules , which are very darkly 

 stained by the alum carmine. At first I presumed that 

 this mass might consist of spermatozoa, which often have 

 been met with in the nephridia of the Syllidae: however 

 the matter could not be fixed , because I found no sexual 

 products in the body cavity, and many of those granules 

 appeared to me to extend into the interior of the epithe- 

 lium cells, and therefore should be considered as the pro- 

 duct of secretion of these cells. 



I regret that I cannot enter more fully into the minute 

 structure of these curious bodies, the material being very 

 scanty and not in too best a state of preservation, after 

 having been for about 25 years in alcohol. 



In the figure 8 I have given two diagrammatical views 

 of a segmental organ, to illustrate the supposed manner 

 of extrusion of this organ ; I presume that by the pres- 

 sure of the fluid of the body cavity the largest portion of 

 the segmental pouch is everted outward, while a small 

 portion, fixed by the internal duct, remains into the body 

 cavity. A muscular fascicle , which I believe could be ob- 

 served sometimes , may have the function to withdraw the 

 pouch and bring her back in the previous situation. Of 

 course it remains somewhat questionable , whether the ex- 

 truding of the pouches is a normal habit of the living 

 animal , or whether it may be caused by the heavy con- 

 traction of the body , as it Avas plunged in the alcohol. 

 However the last supposition seems not very probable to 

 me , because in that case undoubtedly tearing of the inter- 

 nal parts should have taken place , which I could not ob- 

 serve. Moreover it may be remembered that this is not 

 the only example of extrudible pouches observed in Anne- 

 lids, for Ehlers found in the feet of several G lycer a-s-pecies 



Notes from the Leyden Museum, "Vol. XI. 



