146 EXTRACTS AND ABSTRACTS FROM FOREIGN JOURNALS. 



plant with delicate transverse or longitudinal sections, it is easily seen 

 that the circle of the dot proceeds from a hollow or excavation between 

 the contiguous parietes of the vessels ; and the dot, or point, itself is a 

 canal having a tender membrane at its outer end running from the in- 

 terior of the vessel towards this hollow. 



[The author then alludes to varieties resulting from pressure, different 

 appearances of the canal and circle resulting from different sections, &c.] 

 Besides these dots which have a circle, there are others as we have be- 

 fore remarked, met with in a great many plants which are devoid of it. 

 A due examination, especially with transverse or oblique sections of the 

 vessels, shows that between these dots and adjacent lying organs there 

 is no hollow or excavation, but that the dot is formed by a simple gap 

 or chasm of the secondary layer of the tube, and therefore completely 

 simulates the dots of parenchymatous cells, and of reticulated and sca- 

 lariform ducts. 



In punctated vessels septa may be found under two forms. A greater 

 portion of the original partition, having a round hole in its centre, re- 

 mains, or else the partition is broken through by several contiguous 

 transverse spaces, so that they appear like the walls of scalariform 

 ducts. The former kind may be found in Gassy ta glabella, &c. ; the 

 latter in Ilex aquifolium, &c. 



Concerning the development of these vessels we may remark, that in 

 their earlier period of evolution they appear like the other vessels, as 

 rows of large cell-like completely closed tubes, the membrane of which 

 is thin and homogenous and each contains a nucleus. Afterwards a 

 delicate fibrous net is observed on their walls, especially on those which 

 lie next to other vessels. Their further development shows that this 

 net does not depend upon secondary fibres on the inner surface of the 

 wall of the vessel, but that the meshes of the net answer to the after 

 circles of the dots and to indicate the hollows or excavations which lie 

 between the vessels, and that the distinct fibres which surround the 

 meshes are formed through the position of the vascular parieties which 

 remain in connection with adjacent organs. 



[From Valentin's Repertorium, 1841.] 



Van Beneden on Alcyonella. The author remarks that in the same 

 polypoid aggregation both male and female animals exist. The testi- 

 cles of the former, like the ovaria of the latter, are placed behind the 

 stomach. The seminal animalcules leave the testicles and spread them- 

 selves through the interior of the Polyps. The number of males is far 

 less than that of the females. In the interior of the body a circulation 

 is carried on by means of the motion of cilia. The skin, as also the 

 external surface of the intestines are apparently provided with cilia. 

 At the base of the tentacules appears a row of openings for the entrance 

 of water into the interior of the body. The nervous system is appa- 

 rently composed alone of a single ganglion placed above the oesophagus. 

 The young creatures live in a free and isolated state, have a very rapid 



