P. M. DUNCAN ON PARASITIC UNICELLULAR ALG^J. 205 



23. On some Unicellular Alce parasitic within Silurian and 

 Tertiary Corals, with a Notice of their Presence in Calceola 

 sandalina and other Fossils. By Professor P. Martin Duncan, 

 P R.S., V.P.Geol. Soc, &c. (Bead January 19, 1876.) 



[Plate XV.] 



John Quekett described, in his lectures at the Eoyal College of 

 Surgeons in 1851-1852, certain tubes or canals as being very fre- 

 quently met with in the skeletons of corals ; and in his Lectures on 

 Histology, published in 1851, and which contained the subject 

 matter of his previous discourses, he wrote as follows : " Confervoid 

 growths also are very frequently met with in the skeletons of corals, 

 as all these bodies possess animal matter which, decomposing after 

 death, becomes a nidus for the development of conferva? ; and hardly a 

 section can be examined without exhibiting such an appearance as 

 shown in fig. 78"*. This figure shows long, short, and almost 

 straight canals cutting across the normal coral structure at different 

 angles. 



In 1859 Kolliker gave the results of his examination of some 

 corals to the Eoyal Society, in a communication " On the frequent 

 occurrence of vegetable parasites in the hard structures of animals "t. 

 He said : — " All the genera of corals which I investigated contained 

 parasitical fungi, viz. Astraza diffusa, Porites clavaria, Tubipora 

 musica, Corallium rubrum, Oculina diffusa, Oculina, sp., Alloporina 

 mirabilis, Madrepora cornuta, Lopliohelia prolifera and Nullipora 

 alcicornis. The fungi were most frequent in the genera Tubipora, 

 Astrcea, Porites and Oculina, the last three of which contained also 

 many sporangia, which in the red coral were very scarce or 

 wanting." 



Before Quekett lectured, and contemporaneously with his and 

 Kollikcr's researches, Dr. Carpenter J and C. AVedl§ investigated 

 the corresponding tubes or canals in shells ; and the last-named 

 naturalist communicated a most admirable paper on the sub- 

 ject just before Kolliker came forward. Wcdl described and de- 

 lineated the tubes in perfect and in decalcified specimens of shells, 

 and obtained a view of the parasite itself when removed from its 

 nidus in Melania Hollandri under the effects of a dilute acid. He 

 agreed with Quekett in ascribing the parasite to the Conferva?, and 



* John Quekett, Lectures on Histology, vol. ii. p. 153. Parasitic borings 

 corresponding to those noticed by Quekett were described by C. P>. Eose, F.Gr.S., 

 in fossil-fish scales from the Chalk and Kimnieridge Clay, in the Transactions 

 of the Microscopical Society, 1855, p. 7. He figured them ; and his faithful 

 delineations show ramifying tubes and occasional globular enlargements. 

 He attributed them to the operation of infusorial parasites. 



t A. W. Kolliker, of Wiirzburg, Proc. Eoyal Soc. June 9,. 1859, vol. x. 



X Carpenter, Cyclop. Anat. Physiol, art. " Shell." 



§ Wedl, Sitzungsber. d. kais. Akad. d. Wiss. in Wien, B. xxsiii. no. 28. Dec. 

 1858. 



