KOLLJK.ER, ON VEGETABLE PARASITES. 183 



Carpenter. The tubuli, which appear to commence on the 

 exterior, are rare, usually run in a ventical direction through 

 the fibres, but, nevertheless, present such irregularities in 

 their course as, together with the circumstance that in some 

 spots they are wholly wanting, seem to indicate that they do 

 not belong to any typical structure. 



In Rhynchonella nigricans, Terebratula Caput Serpentis, 

 and T. resupinata, no vestige of these fine tubules was per- 

 ceptible. On the other hand, in Leptcena lepis, from the 

 transition-formation, Wedl has found vegetable parasites. 



6. Gasteropoda. 



The canals in these shells, which were first noticed by 

 Claparede, have been referred by Wedl to a vegetable para- 

 sitic growth — an explanation whose correctness admits in 

 part of easy proof, inasmuch as, in certain cases, distinct 

 sporangia may be observed on the canals. I have examined 

 the following shells : 



(a) Murex irunculus. 



In the outermost layers of the shell may be observed a 

 horizontally spreading mycelium, constituted of anasto- 

 mosing fungus-filaments, of whose delicacy it is difficult to 

 form any idea, since the meshes of the plexus are in many 

 places hardly double the diameter of the filaments. 



Very numerous straighter filaments arising from this 

 layer of mycelium passed inwards, penetrating all the laminae 

 of the shell either vertically or obliquely, and throwing off 

 frequent branches. On arriving at the innermost lamina, 

 and not unfrequently even before doing so, these filaments 

 would again spread out in a horizontal plexus. No sporangia 

 could be perceived. The fungus-filaments measured, for the 

 most part, about 0-001'", though some reached a diameter of 

 0-002'". 



[Other species of gasteropod shells examined by the author, 

 and which presented appearances more or less similar to the 

 above, are :] 



Murex brandaris. Haliotes, sp. 



Vermetus, sp. Tritonium cretaceam. 



Turbo rugosus. Litorina litorea. 



Aphorrhais pes Pelecani. Terebra myurus. 



Whilst in species of Oliva, Cyprma, Nautilus pompilius, 

 and Aptychus, he was unable to detect any growths of the 

 fungus character. 



