348 OBSERVATIONS ON THE CHLORAEMIDAE, 



In a living specimen of Siphonostomum affine, however, it was 

 seen that the vessel in a dilated state is considerably larger than the 

 enclosed cardiac body. The latter consists of longitudinally arranged 

 lobes, which in all the specimens examined had lost their cellular 

 structure, — this being represented in the case ofCoppingeria merely 

 by nuclei and faint traces of cell-bodies. An examination of n^ 

 sections confirms Cunningham's statement that there is no connec- 

 tion whatever between the cardiac body and the intestinal epithel- 

 ium. In front it is continuous with the wall of the vessel ; behind 

 it is completely free and moves passively with the peristaltic con- 

 tractions. Cunningham describes a lumen as being present in the 

 cardiac body, but in this I think he is mistaken. The lobes are 

 in some parts slightly separated from one another, leaving fissures 

 here and there ; sometimes there is a star-shaped fissure in the 

 middle, but where this is the case the space is filled with blood. 

 Whatever may be their condition at an earlier stage, the lobes in 

 the specimens I have examined are solid and contain no lumen. 



VI. Alimentary canal and nephridia. 



The special features of the alimentary canal in this family have 

 been described by various authors, and I have little to add with 

 regard to Copjringeria to what has been already published. The 

 anterior part is in the form of a narrow oesophagus, with a high 

 epithelium of ciliated cells. The wide stomach, with its anteriorly 

 projecting ccecum, is thin-walled, with a low epithelial lining ; it 

 is filled with particles of mud containing the remains of many 

 microscopic organisms. The narrow intestine has a comparatively 

 thick wall, with an epithelial layer of elongated ciliated cells ; its 

 lumen contains no food particles. The peculiar orange colour of 

 the stomach in its anterior portion, which appears to be general 

 in this family, is, of course, not to be detected in a specimen so 

 long preserved in spirits, but is well-marked in Stylarioides cinctus. 

 In this species the hinder part of the stomach (fig. 21) is bent on 

 itself so as to run obliquely forwards for a little distance before 

 passing into the intestine ; the latter is bent round in the way 



