298 NATURAL HISTORY SOCIETY OF DUBLIN. 



their narrow peduncles, or necks, continuous with a duct (Fig. 2, i), 

 which opens into the gut immediately above its termination. This 

 duct was much more distinct in the females. In one specimen a spur 

 (Fig. 2, h) was seen distinctly passing backwards to the body wall from 

 the anterior extremity of one of the caeca. Concerning the nature of these 

 bodies we may hazard several conjectures ; they might be the representa- 

 tive of such a compound or branched alimentary canal as is found in other 

 Entozoa and in Annelida, or they might be special secreting organs. "With 

 regard to the first part of these theories, it is known that intestinal caeca 

 do occur in other species of Entozoa. Mehlis* describes several of these in 

 various species of Ascaris ; and Leidy f figures a large caecum in Thelasto- 

 mum appendiculatum. In these, however, the diverticula arise high in the 

 digestive tract, near the point of junction of the stomach and oeso- 

 phagus, and open directly below the oesophageal constriction, which 

 is far from being the case in the subject before us. Their granular na- 

 ture, narrow necks, and constant low position, as well as their number, 

 and the length and distinctions of their ducts, have led me to think 

 that they might, perhaps, be organs of excretion, mayhap the earliest 

 traces of renal organs in the animal kingdom. | It may be remem- 

 bered with regard to this, that the presence of distinct secreting glan- 

 dular organs in Nematoid Entozoa is no new fact ; for Professor Owen 

 has described salivary caeca as existing in Gnathostoma aculcata. Other 

 glands have likewise been described, which I will notice more par- 

 ticularly hereafter. Erom the sides of the intestine below these caeca 

 fine lateral threads pass off, and are lost on the body wall above the 

 anus ; these seem to suspend the gut and the cseca, and might be named 

 retinacula. 



The nervous system, if any existed (which we may suppose to be the 

 case from analogy), completely eluded my reach. There are, as I have 

 before stated, dorso-ventral Hues, and in some individuals the ventral was 

 much the larger and more distinct. It may be nervous in its nature, 

 but presented no distinct character by which I could recognise it as 

 such. 



On the ventral aspect of both sexes, corresponding to a concave and 

 well-marked sinuosity or depression of the superficial abdominal line, 

 a very small bilobate aperture was visible on the body wall opposite, 

 or a little above the level of the upper dilated end of the intestine ; in 

 one or two, however, it was much below this point. Erom this a small 

 tube (Eig. 1, c; and 2, m) passes for a very shortdistance inwards, and then 

 gives off four small prolongations, two of which pass forwards, and are lost 

 in the anterior part of the lateral lines, while the other pair pass back 

 into the posterior portion of the same lines, where they expand into very 

 small dilatations (Eigs. 7 and 8), beyond which they are not traceable. 

 It was with very considerable interest that I detected this structure, 



* "Isis,"for 1831, p. 91. 



t " Smithsonian Contrib.," Part 5, p. 49, Plate VII. 



% "Annals of Natural History," July, 1865. 



