Johannes Fibiger and Hjalmar Ditlevsen: Spiroptera neoplastica n. sp. 23 



A part of the mucous membrane from the ventricle of a rat enclosing the 

 Spiroptera, when seen under the mieroscope first of all presents the winding passage 

 in which the worm is placed. Scattered round the worm eggs will be found in the 

 epithelium. It probably may be beyond doubt that the pairing takes place in this 

 passage in the mucous membrane, as the worm does not leave its place here in order 

 to seek refuge in the lumen of the stomach. To be sure, it may sometimes be ob- 

 served projecting into the lumen with a shorter or longer part of its body, but 

 no specimen has been found free in the stomach. Sometimes two specimens are found 

 in the same passage, a male and a female. They are then placed quite near to each 

 other, the front part being turned in the same direction. However, a pairing never 

 is observed although a case as the one just described may probably be explained as 

 the introduction ; or possibly the pairing itself may have taken place. 



In the mature female eggs are constantly evacuated through the vulva; the 

 vagina as a rule contains eggs in the aet of leaving the worm. Round the female the 

 epithelium of the stomach of the host is seen to contain eggs. When by desquamation 

 of the epithelium, afterwards passed into the lumen of the stomach, the eggs are mixed 

 with the contents of the latter and fmally evacuated with the excrements, in which 

 on microscopical examination they are easily found. 



The egg is very regularly egg-shaped, thickest in the middle and evenly tapering 

 towards the poles; its maximal diameter is about 60//, the minimal being about 40//. 

 In Optical sections the shell is found somewhat thickened at the poles, in this respect 

 the egg is quite similar to that of Spiroptera obtusa as figured by Iæuckart. The shape 

 too resembles that of the latter. See Leuckart: Die menschhchen Parasiten II 

 fig. 85 p. 113, and present paper PL I fig. 8. 



Under high magnifying power the e%^ presents a distinct line of demarcation be- 

 tween the thinner middle part of the shell and the thicker field at the poles; which 

 seems to be of great consequence when the young ones are 

 about to leave the egg. In the uterus, however, all stages of 

 development are present; in ripe eggs the larva is found coiled 

 up; at this stage it is thickest in its front end, decreasing 

 evenly in width towards the tail. 



The very day after the feeding of the cockroach on ripe 

 eggs the intestinal canal of the latter contains free larvæ and 

 empty eggs simultaneously. An extraordinary number of eggs 

 apparently, however, is uninfluenced by the new conditions. This ®' 



especially is the case when the cockroaches are fed on eggs originating directly from 

 mature females, instead of being fed on rat 's excrements; and the reason is, prob- 

 ably, that in faet several of the eggs are not ripe for hatching, although by way of 

 microscopical examinations it is not possible to prove this. Most likely some changes 



