THE ANATOMY OF THE MADREPORARIA. 15 



Erratum. 



In my previous paper (4) PI. XL, fig. 1^, the septa were 

 wrongly numbered; they should have been marked 1, 4, 3, 4, 

 2, 4, 3, 4, 1, reckoning on each side from the central '^direc- 

 tive" septum, D. 



Literature. 



1. Milne-Edwakds. — ' Hist. Nat. d. Coralliaires,' iii, p. 148. 



2. VON Koch. — ' Jen. Zeitschr.,' Bd. xi. 



3. MosELEY.— ' Quart. Journ. Micr. Sci.,' Oct., 1882. 



4. Fowler.— ' Quart. Journ. Micr. Sci.,' Oct., 1885. 



5. Wilson.— 'Mittli. Zool. Sta. Neap.,' Bd. v. 



6. VON Heidek. — ' Sitz. k, Akad. Wissench.,' 1879. 



7. Dana. — ' Zoopliytes of the Wilkes Expedition.' 



8. V. Koch.—' Morph. Jahrb.,' Bd. vi. 



DESCRIPTION OF PLATE I, 



Illustrating Mr. G. Herbert Fowler's Paper on " The Anatomy 

 of the Madreporaria.'' 



a. Polyp cavities, cut obliquely, a'. Polyp cavities, cut transversely. Ab. 

 Abaxial (ventral) septum. Aa\ Axial (dorsal) septum. C. Costse. c. c. Cen- 

 tral cavity, continuous with the apical polyp, c^. External longitudinal canals 

 between the costse. c^. Internal longitudinal canals, c'. Radial and trans- 

 verse connecting canals. Co. Coralluni of the main branch, d. Cut edges of 

 the endoderm and mesoderm lining the coelenteron. ecL Ectoderm, en. En- 

 doderm. exL h. to. External body wall of ectoderm, mesoderm, and endoderm. 

 M. Mesentery, showing the endodermal swelling. me. Mesoderm lamella. 

 S. Septum. S. C. Septal Columella-plate. St. Stomatodseum. Th. Theca 

 of polyp. Z. Zooxanthellse. x. Fusion of costai over ext. long, canals. 

 All except Fig. 10 are from Madrepora Durvillei. 



Fig. 1. — Dorsal view of the corallum of two fragments of a branch, 

 bearing cahcles, and branchlets formed of other calicles. 



Fig. 2. — Ventral view of the same specimens ; one of which is entirely 

 bare of calicles on this side, and on the other only a few are present. 



Fig. 3. — Transverse section of a branch, showing the polyp cavities, the 

 central cavity, and the canals running in various directions. The concentric 



