IProm the Proceedings of the Royal Society, No. 36, 1859.] "On the frequent occurrence of Vegetable Parasites in the Hard Structures of Animals." By Professor A. Kolliker, of Wiirzburg. Communicated by Dr. Sharpky, Sec. R.S. Received May 30, 1859. As far as I am aware, Quekctt has been the first to point out that vegetable parasites, viz. Conferva, occur frequently in the skeleton of Corals (Lectures on Histology, vol. ii. p. 1.53. fig. 78. and p. 276) ; but although he mentions in the same place that the tuhuli described by Carpenter in the shells of Bivalves have also a great resemblance with Confervce, he did not venture any further step, and he adheres to the view of Carpenter, who regards them as a typical structure. Some years later. Rose ("On Parasitic Borings in Fossil Fish- Scales," Transactions of the Microscopical Society of London, vol. x. p. 7, 1855) discovered a pecuhar tubular structure in fossil fish- scales, which he regarded as being occasioned by parasites, and possibly by Infusoria, but he was not able to give any good proof of this hypothesis. The same must be said of E. Claparede (Miill. Archiv, 1857, p. 119), who found similar canals in the test of Neritina fluviatilis, and showed that they do not really belong to the shell, without being happier in determining the nature of the parasite, only suggesting that it might possibly be a sponge. Such was the state of things, when Prof. Wedl of Vienna and I, Independently of each other, took up the question. The observations [f Wedl, which concern only the parasites of the shells of Bivalve id Gasteropods, were commimicated to the Vienna Academy on the tub of October, 1858, and are therefore previous to my own, which ;re presented to our Wurzburg Society on the 14th of May, 1859 ; lit I received Wedl' 8 memoir only on the IGth of May, and may lerefore say that my observations, which are also extended o\er many |ore groups of animals, were quite independent of those of the istrian microscopist. This being the case, it may be regarded as a »d proof of the correctness of our observations and the truth of r conclusions, that we agree m the principal facts, there being 2 only this discrepancy between us, that Wedl calls the parasites Con- fervcB, whilst I regard them as Unicellular Fungi. The botanists will decide this question better than we; only I beg leave to say, that all the numerous parasites observed by myself were unicellular, and that the sporangia were quite of the same kind as those of uni- cellular fungi. I may further add, that the frequent anastomoses of the parasitic tubes remind one of the anastomoses observed in the mycehum of some unicellular fungi, whereas such connexions have not yet, so far as I know, been observed amongst the Confervce. I now give a short enumeration of the animals in whose skeleton I observed these vegetable parasi es. 1. SpongitB. Two undetermined species of sponges, which I got through the kindness of Mr. Bowerbank, show a great many parasitical tubes in the horny fibres of their skeleton. These are most elegant and numerous in one species from Australia, in which the tubes form a superficial network in the outermost parts of the horny sponge-fibres and more straight canals in their interior, and possess a great many round sporangia, which in some cases even showed young outgrowths in form of short ramifying tubes. 2. Foraminifera. In an extensive collection of sections of Foraminifera which I owe to the kindness of my friend Prof. Carpenter, there were many genera which showed numerous filaments of fungi in their test itself, viz. Polystomella, Orhitolina, Heterostegina, Am2)histegina, Cal- carina, Alveolina, and Operculina. The last genus shows best that these parasitic tubes, which sometimes are very large, are quite different from the two kinds of tubes rightly described by Carpenter as belonging to the test itself. They generally run at right angles to the finer tubuli, and are easily distinguished from both kinds of typical tubuli by their irregular course, and by their frequent branch- ing, and even anastomosing. They are absent in many specimens of the above-named genera, and could not be found in Cycloclypeus, Nummulina, and Nonionina. 3. Corals. All the genera of Corals which I investigated contained parasitical fungi, viz. Astrcea diffxisa. Pontes clavaria, Tubipora musica, 3 Corallium rubrum, Oculina diffusa, Oculina, sp., AUoporina mirabilis, Madrepora coniuta, Lobalia prolifera, Millepora alcicornis, Fungia, sp. The fungi were most frequent in the genera Tubipora, Astrcea, Pontes, and Oculina, the last three of which contained also many spo- rangia, which in the red coral were very scarce and often wanting. 4. Bivalves. I agree with Wedl that the tubuli described by Carpenter in the shells of Bivalves are all parasites. Many of them agree in every respect with those found in other hard structures of the Inver- tebrata, of whose parasitical nature there can be no doubt ; and even possess sporangia, as those of Thracia, Lima, Cleidothcerus, Anemia, Ostrea, Meleagrina. With respect to those of the genera Litho- domus. Area, Pectunculus, Nucula, Cardium, it is true that their straight course and more regular distribution speak in favour of their typical occurrence ; but as in some cases true parasites also are very regularly distributed through the shells, there can be no doubt that even these do not really belong to the structure of the shells. 5. Brachiopods. The test of some Terebratulce shows, besides the large well-known canals, minute tubuli nmning straight through the fibres. A vertical section of Terebratula australis, which I got from Prof. Carpenter, showed that the minute canals referred to belong to a vegetable parasite of the same kind as those of the Bivalves. 6. Gasteropoda. Nearly all examined Gasteropods, viz, Cerithium tuberculatum, Aporrkais pes-Pelecani, Turbo rugosus, Murex brandaris, Murex tmnculus, Haliotis, Vermetus, Trochus, Littorina littorea, Terebra myurus, Tritonium cretaceum, contained vegetable parasites in their shells, and in some these were as numerous as in the Bivalves, and showed also sporangia. Besides these fungi, the shell of Trochus also contained in its most superficial layers unicellular pyriform algfF with green contents. 7. Annelids. Even in this group the unicellular parasites were found, viz. in the calcareous tubes of two Serputce from the Scotch coast. 4 8. Cirrhipeds. The same parasites also occurred very numerously in the shells of a large Balanus. On the other hand, the genera Diudema and Lepas were free from them ; and with regard to the straight tubes of PoUi- cipes described by Quekett, which also occur in Tubicinellu, I am inclined to reckon them amongst the typical structures. 9. Fishes. The scales of Ber}/x ornatus, from the clay, contain very numerous and pretty parasitic structures, which almost totally agree with those figured by Rose in his fig. 5. They undoubtedly also belong to the simplest form of fungi, but are of greater interest, inasmuch as they are fossil and' seem to constitute a new genus. I was not able to find parasites in any other fish-scales, notwithstanding that I examined scales of all living and many fossil species of Ganoids and many Teleostei. These are' the facts which I have been able to gather, up to this time. I have no doubt that all will ageee with me in regarding this question as one of great interest for the zoologist as well as for the botanist. The former will now be obliged to study these parasitical structures as thoroughly as possible, in order to decide which tubular structures of the hard tissues of animals are typical and which are not ; and for the botanist a new field of investigation is opened, which not only draws attention by the somewhat strange forms offered for investigation, but is also of great interest in a physiological point of view. It seems to me probable that the parasites dissolve the car- bonate of lime of the hard structures into which they penetrate, by means of exudation of carbonic acid, which secretion would seem to take place only at the growing ends of the fungial tubes, as they never lie in larger cavities, but are always closely surrounded by the calcareous mass. In some cases, as in the horny fibres of sponges, it seems probable that the parasites simply bore their canals by mechanical force, as is the case when vegetable parasites make their way through the cell-membranes of Confervce or other plants. Besides this, it deserves also to be remembered that nearly all the parasites here spoken of occur in marine animals. In concluding this notice, I may further mention that these parasites afford an excellent means for demonstrating the double- refracting 'power of the shells of the several genera mentioned in 5 this comniuuicatioii. I was first struck with this fact in examining a horizontal section of Lima seabra obtained from Dr. Carpenter, and finding that many tnbuli appeared double. In following this matter, it was easy to show that all the tubuli running in a certain direction, and in an oblique way through the section, appeared simple at the upper surface of it, and became double in the inferior layers, so that the distance of the two images increased with the shortening of the focus. When the preparation was inverted, the reverse was the case. The same phenomena as in Litna were also observed in Anomia, Ostrea, Murex truncatus. Turbo rugosus, Tritonium cretaceum, and Balanus, the shells of which animals have therefore all such a structure, that they refract the light in the same way as the well-known double-refracting crystals*. • According to Brewster (Bibl. Univ. de Geneve, 1836. ii. 182), who seems the only person who has hitherto observed the doui)le- refracting power of a shell, viz. of tlie mother-of-pearl, that shell {Meleagrina) shows the same phenomena as the donble-axed double-refracting Arragonite, on which question I am not as yet able to give an opinion.