ANCYLOSTOMUM DUODENALE. 385 



furnished with four strong teeth on the projecting portion of the 

 upper margin. The oral orifice is turned towards the dorsal 

 surface; that is, towards the surface opposite to the sexual and 

 anal orifices. The animal attaches itself with its mouth so 

 firmly to the mucous membrane, that the mouth is easily torn 

 away when it is detached by force. Its nourishment is blood, as 

 the intestine filled with this fluid proves. In the region of the 

 middle of the oesophagus, the secretory organ first found in the 

 Strongyli by Von Siebold opens outwards, and forms behind the 

 orifice an ampulla, produced by the union of two sacs, which 

 pass backwards in a somewhat tortuous form, and a little way 

 behind the commencement of the intestine become converted into 

 fusiform (glandular) bodies. The contents of this organ are 

 thickly fluid and finely granular, with a clear and apparently 

 rather solid nucleus, of a perfectly homogeneous appearance in 

 the middle of the two glandular bodies. The double penis is 

 very long and slender. In a pair once found in coitu, the male 

 was firmly adherent to the vagina of the female, by his caudal 

 valve. 



Primer, as well as Diesing, has misunderstood the parts of the 

 mouth in Ancylostomum. The former says, it fixes its four-fold 

 sucking proboscis, with forty hooks, upon the mucous membrane. 

 Von Siebold says upon this, that, as the spacious oral cavity of 

 this worm is bent round with its wide aperture towards the back, 

 the lower margin of the oral aperture is more strongly produced 

 than the upper, as we perceive in a lateral view of the worm. 

 Now within this lower margin, but not upon the upper one, and 

 consequently at the bottom of the oral cavity, stand the four 

 teeth bent round backwards, springing close together from four 

 elevations of the horny walls of the oral cavity, but not arranged 

 in the manner of a cross, as Diesing has it, and as is the case in 

 Strongylus tetracanthus. 



The two conical projections are cutaneous papillae, which 

 project from a small cavity in the skin in the middle of the cla- 

 vate oesophagus. They are processes of the transparent general 

 integument, in the middle of which there is a small acute process 

 of the substance situated under the skin. According to Von 

 Siebold, they are perhaps tactile organs, employed by the worm 

 when adhering by suction to the human mucous membrane. 



EvenDubini spoke of corpora fusif or mia, and also figured them. 

 They make their appearance in both sexes, and are analogous to 



B B 



