PARASITIC WITHIN SILURIAN AND TKRTIARY CORALS. 211 



Fig. 5. Tube with conidia, from an American Lower-Silurian Foramiuifer, X 

 400. 



6. Tube near the edge of Goniopkyllum pyramidale, showing the entrance 



of the tube from the outside, X 350. 



7. Tubes in Goniopkyllum pyramidale, alternately dark and light. 



8. Tubes with conidia in Goniopkyllum pyramidale, x 400. 



9. Tube of moniliform appearance from Goniopkyllum, X 350. 



10. Tubes cut across, showing their lumen, from Goniopkyllum, X 350. 



11. Tubes in Calceola sandalina, from the Devonian, X 350. 



12. Large tube, opening at the surface of Calceola sandalina, reaching in 



but a short distance, and containing oospores, some of which have 

 germinated and formed canals, which radiate from the end of the 

 tube, x 400. 



13. A similar tube from Calceola sandali?ia, containing oospores, x 400. 



14. Tube with spherical spore-sac, from Goniopkyllum pyramidale, X 350. 



Discussion. 



Prof. Morris expressed his agreement with the author's con- 

 cluding remarks, and thought that the discovery of these low para- 

 sitic organisms so far back in geological time was especially interes1>- 

 ing, as showing the identity of conditions in all periods. He 

 remarked that another tubular structure different from those de- 

 scribed by Dr. Duncan had been observed by M'Coy in Pterinea de- 

 missa, from the Wenlock Limestone, and referred to Cliona. This 

 latter structure had also been observed in some Jurassic and Creta- 

 ceous Mollusca. 



Mr. Etheridge agreed with Prof. Duncan in regarding these 

 parasites as Algae, and remarked especially the similarity of the 

 phenomena to those presented by many freshwater Algae, referring 

 especially to Vaucheria. The continuity of conditions of life thus 

 manifested was, he thought, very remarkable. He stated that 

 numerous sections of Scandinavian palaeozoic Corals given to him by 

 Sir Roderick Murchison were full of tubular forms like those de- 

 scribed in the paper. 



Prof. Ramsay asked Prof. Duncan to state how much of the con- 

 tents of his paper was to be regarded as new. 



The Author, in reply, suggested that a similar question might 

 just as well be put to the author of every paper. His new points 

 were the establishment of the extension of these parasitic organisms 

 to a much earlier period than any in which they had previously been 

 recognized, especially their occurrence in the very ancient Corals to 

 which he had referred, and certain particulars as to their characters 

 and mode of occurrence. The parasitic Algae could not be con- 

 founded with such sponges as that found by M'Coy or with Cliona, 

 as their tubules were very much smaller than those formed by the 

 sponge ; in fact the tubules of the parasitic plants had about the 

 same diameter as the spicules of Cliona. 



