1,08 Professor Yakovlev — On Rugose Corals. 



mineralogical or geological grounds, which could impair the position 

 taken up. The criticisms on theoretical grounds which have been 

 brought forward have not invalidated the claim for these structures 

 which the writer has brought forward. It is proposed to present 

 the slides to the British Museum, so that they can be made available 

 for inspection and reference. 



EXPLANATION OF PLATE VII. 



Fig. ] . — Frodingham Ironstone from Jurassic rocks of Lincolnshire. From 

 interior of fossilized organic fragment. Shows hyphas, one bearing 

 a fully developed terminal sporangium, a = sporangium, = hypha, 

 c = calcite matrix. x 530. 



,, 2. — Frodingham Ironstone from Jurassic rocks of Lincolnshire. Shows 

 two sporangia of PliycomycitesFrodinghamii. In the left sporangium 

 (c), partially extruded from it, is seen a spore (b). a is a portion of 

 a small oolite. x 166. 



,, 3. — Organic remains in Frodingham Ironstone. At a is shown a fragment 

 in which fungal hyphaj were found. x 18. 



,, 4. — The organic fragment marked a in Fig. 3 shown on a larger scale. 

 The fungal hyphoe are distinctly visible. x 116. 



,, 5. — From Dunliath Ferruginous Limestone (Jurassic, N.W. Scotland). 

 Eemains of animal cells, x 466. 



., 6. — A semi-diagrammatic sketch of a portion of an organic fragment in 

 the Dunliath Ferruginous Limestone. Inside the fragment are seen 

 the remains of animal cells and of fungal hyphas. The branched 

 tubules are the hyphse and the dark rounded fragment the animal 

 cells. 



III. — On the Organization of the Rugose Corals and the Origin 

 op their Characteristic Peculiarities. 



By Professor N. N. Yakovlev, Petrograd, Russia. 



(PLATE VIII AND FOUR TEXT-FIGURES.) 



DURING the last ten years I have published a series of memoirs ' 

 on different questions concerning the morphology and biology 

 of the Rugose Corals. In these memoirs I have elucidated the 

 ground-form of the polyparium of the solitary Rugosa, the mode of 

 its attachment to the substratum, the origin of the characteristic 

 arrangement of the septa, and the origin of the fossulae in dependence 

 on this form and attachment. I have established the connexion 

 between the form of the polyparium of the Rugosa (including that 

 of the fossulae) and the life of these corals in definite environmental 

 conditions. 



1 N. Yakovlev, "Die Fauna der oberen Abtheilung tier palaeozoischen 

 Ablagerungen im Donetz-Bassin. II. Die Korallen " : Mem. Com. g^ol. 

 St. Petersbourg, N.S., livraison xii, 1903. "A contribution to the Characteristic 

 of Corals of tbe group Rugosa": Ann. Mag. Nat. Hist., ser. VII, vol. xiii, 

 pp. 114-17, 1904. " Ueber die Morphologie und Morphogenie der Rugosa " : 

 Ver. Russ-k. Min. Ges. St. Petersbourg, vol. xli, pp. 394-415,1904. "Die 

 Entstehung der charakteristischen Eigentiimlichkeiten der Korallen Rugosa " : 

 Mem. Com. geol. St. Petersbourg, N.S., livraison lxvi, 1910. " Les recifs 

 coralliens existent-ils clans lepaleozoique?" : Bull. Com. geol. St. Petersbourg, 

 vol. xxx, No. 10, pp. 847-57, 1911. " Studien iiber die Korallen Rugosa " : 

 Mem. Com. geol. St. Petersbourg, N.S., livraison xcvi, 1914. 



