ON DINOPHILUS GIGAS. 115 



bulb (fig. 7, m. ph.), lying ventral to the commencing stomach, 

 while the horizontal portion closes and in section disappears. 



From a consideration of these sections^ and from the dia- 

 grammatic longitudinal section given in fig. 11^ it is obvious 

 that the pharynx of this Dinophilus has the same structure as 

 that described by Korschelt, Hallez, and others, in the better 

 known species of the genus. 



I have, however, been unable to make the animal evert its 

 pharynx, as some species are said to do. Irritation with fresh 

 water, acetic acid, &c., or stimulation by pressing the cover- 

 slip, were equally useless in this respect. Further, in no case 

 did my preserved specimens evert the pharynx in dying. 



The oesophagus has already been seen; it is a narrow tube 

 lined by a ciliated epithelium (figs. 4 — 6), which opens, at 

 about the beginning of the second segment, into the large, 

 wide stomach (figs. 1, 2, and 8, st.), distinguished by its wide 

 lumen and its granular, brilliantly pigmented epithelium. The 

 cilia of the stomach are very long, and during life their action 

 produces a most violent agitation of the contents of the organ. 

 In the sixth segment the stomach bears on its ventral side 

 a small pyloric opening (fig. 9), leading into an intestine, 

 which is also ciliated. The stomach is prolonged, as a kind of 

 csecum, for a short distance behind the pylorus. The intestine 

 passes backwards through the seventh segment, diminishing 

 gradually in diameter, till at last it narrows suddenly and opens 

 to the exterior in the dorsal middle line. 



The reproductive organs are in both sexes similar to those 

 described by Korschelt^ in the female of D. apatris; that is, 

 they each consist of a Y-shaped mass of cells, the anterior 

 limbs of which lie under the posterior half of the stomach 

 (fig. 8, To), while the posterior unpaired limb lies under the 

 intestine, or else, as is more generally the case (fig. 9, me.), 

 pushes this latter organ to one side. The two sexes are similar 

 externally, until the ripening of the reproductive cells renders 

 the ova or spermatozoa distinguishable through the skin. At 

 the time of sexual maturity the gonads enlarge, so as to com- 



' Loc. cit. 



