NEUrvOSPORIDIUM. 83 



Neurosporidiuin still further; but it is to be noticed that 

 the central, uninucleate cells that one would take to be the 

 spores, are enclosed within a Avail composed of a single layer 

 of regular cells, and not by a structureless cyst or capsule. 

 In the explanation of the figure, the parts marked hp. are said 

 to be ''sections apparently of the shield pores in their pro- 

 gress outwards," but it is highly improbable that the proboscis 

 canals could, in a section taken at right angles to the buccal 

 shield, be so cut as to present a circular outline, and even 

 then the pi'esence of the third body is difficult to explain, for 

 the proboscis canals are short, and with firm walls of closely- 

 set epithelial cells, and could not, even in the most contorted 

 polypides, be cut across twice in the same section. 



In view of the close relationship which is admitted to exist 

 between Balanoglossus and Cephalodiscus it is worthy 

 of mention in this connection that Spengel' has found in the 

 coelom of a species of Balanoglossus (Ptychodera 

 minuta) masses of small, uniform, nucleated cells which he 

 is inclined to regard as of a j^arasitic nature. Caullery and 

 Mesuil ' agree with Spengel that these bodies are parasitic 

 organisms, and they refer them provisionally to the new 

 order of the class Sporozoa to which they have given the 

 name Haplosporidia, the order in which we propose to place 

 the Neurosporidium of C ephalodiscus. 



Material and Methods, 



The specimens of Cephalodiscus uigrescens obtained 

 by the " Discovery " were fixed, some in a 5 per cent, solution 

 of formalin, some in Perenyi's fluid, and some in picric acid 

 solution. Serial sections of the polypides were cut for the 



1 ' Fauna and Flora des Golfes von Neape!,' Monogr. 18, 1893, pp. 661, 

 662; pi. 2, figs. 19, 20; pi. 3, llgs. 50, 51; pi. 4, figs. 60, 61, 76, 79, 80; 

 pi. 5, fig. 105. 



- "Haplosporidies," 'Arch, de Zool. Exp. et Gen.,' iv, 3, 1905, p. 164, and 

 pi. 13, fig. 125. 



