180 KOLLIKER, ON VEGETABLE PARASITES. 



(i) 



Delicate, rather numerously branched filaments, from 0001"' 

 in diameter to some of extremely minute dimensions. No 

 sporangia. 



(Ic) Cor allium rubrum. 



In four sections, only in one were observed a few fine, 

 evidently fungus-filaments without sporangia. 



(/) Isis hippuris 



Also contained only a few of rather thick fungus-fila- 

 ments. 



(m) Madrepora muricata 



Exhibited rather numerous fine, beautifully branched fungus • 

 filaments, with indications of sporangia. 



(n) Tubipora musica. 



The substance of this calcareous skeleton was everywhere 

 pervaded with very numerous finer and coarser fungus-fila- 

 ments, whose ramifications, however, presented no sporangia. 



In the hard structures of other polypes, I have not yet 

 succeeded in detecting any parasites. Among these were 

 various species of A ntipathes, Gorgonia, Pavonaria, Pennatula, 

 and Virgularia. In the two latter genera, it is true that 

 tubular structures occurred in the calcified axis, which have 

 been already noticed and figured, by Quekett, form Virgularia 

 (< Histol. Catal.,' i, p. 221, PL XIII, fig. 11), but these are 

 unbranched, and so regularly disposed that they can scarcely 

 be looked upon in any other light than as typical struc- 

 tures. 



4. Acephala. 



The well-known researches of Dr. Carpenter have esta- 

 blished the fact that in the shells of many bivalves special 

 tubular systems exist, which have been regarded by that 

 author as typical. These tubuli have subsequently hern 

 mentioned by Quekett, in his ' Histological Catalogue/ part i, 

 in describing the preparations presented to the College of 

 Surgeons "by Dr. Carpenter, but without any further expres- 

 sion of opinion as to their nature. In another place, however 

 ('Lectures on Histology/ vol. ii, pp. 153,270, 277), Professor 

 Quekett compares them with Conferva?, though ultimately 

 agreeing with Carpenter, and supposing that, like the canals 



