132 REPORT OX THE SPECIMENS OF THE GENUS MILLEPORA. 



Plate XVI. 



Fig. 1. Large nematocyst of Millepora, the outline copied from Moseley. In the thread a 

 thin spiral fibril may be seen in many specimens. The mode of attachment of this 

 fibril to the cyst wall is uncertain. 



Fig. 2. Large nematocyst drawn with the assistance of the Camera lucida from a section 

 of one of Dr Willey's millepores, showing a spiral fibril running through the thread 

 distally and proximally coiled in the cyst. 



Fig. 3. A portion of that part of the thread of the large nematocyst which is beset with 

 spirally arranged rows of thorns. In this part of the thread the spiral fibril drawn 

 in Fig. 2 cannot be clearly traced but it appears again in the portion of the thread 

 beyond the thorny part. 



Fig. 4. Drawn from a section of a millepore given to me by Professor Haddon. Shows a 

 large exploded nematocyst deeply seated in the tissues below the Ectoderm. Ect. 

 Ectoderm, End. Endoderm, z. zooxanthella. 



Fig. 5. An unexploded nematocyst in its cnidoblast drawn from a section of the same 

 material as fig. 4. n. nucleus of the cnidoblast, ps. a pseudopodium of the cnidoblast. 

 Details of the thread coiled up in the cyst are omitted. 



Fig. 6. One of the small kind of Millepore nematocyst. Outline drawn with camera from 

 a section of a gastrozoid tentacle in Dr Willey's material. 



Fig. 7. Outline sketch of canal system as seen in vertical sections showing the manner in 

 which the Bacterium milleporae (bact.) occurs in zoogloeae, at the surface and in the 

 canals. 



Fig. 8. The Bacterium milleporae as seen by Zeiss's 2 mm. oil imm. 



