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



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The shape of the capsule is somewhat differing according to the various individuals; 

 most probably this is proportionate partly with the space which is left to the disposal 

 of the worm during the aet of encysting, partly with the state of contraction of the 

 surroimding muscles. The circumference generally is nearly circular and somewhat flat- 

 tened, the capsule being thus lenticular and thickest in the middle. Often, however, 

 it has a more or less longish shape almost as a somewhat flattened egg. 



As a rule the worm if not disturbed will keep rather quiet withiri its capsule, 

 small slidiiig movements being observed as the spiral is contracted or relaxed; greater 

 movements no more than changing of place will occur. 



When isolated from the surrounding muscular tissue and placed under a cover- 

 slip in a solution of physiological common salt the larva within its capsule will 

 show itself most extraordinarily animated, owing to the unusual conditions. It 

 moves about inside the capsule in a most energetic way, describing with its body now a 

 spiral, now a figure of eight, the head sometimes in the centre of the capsule, some- 

 times in the periphery. 



Under the microscope the isolated capsule presents itself very thick-walled, com- 

 posed of a thick granular mass the consistence of which is similar to that of a thick 

 protoplasm. A membrane of connective tissue will generally not be found. The 

 capsule probably consists of degenerated muscular tissue from the surrounding muscles. 

 After a while the movements of the larva grow more animated; it begins trying to 

 break through its capsule, now and then putting its head into the wall of the capsule 

 which very easily yields to the pressure. As the worm draws back into the cavity a 

 canal is left which will contract but very slowly. By 

 and by several bored passages may be found in the 

 wall, reaching more or less deep into it and often 

 wound according to the direction of the worm. Finally 

 it may happen that the worm gets quite through the 

 wall and escapes. This faet has been dwelt on at 

 some length as it seems to throw light upon the pe- 

 culiar consistency of the capsule. Most likely the un- 

 usual toughness, which is evidently characteristic of it, 

 will be of great consequence to the larva, sheltering it 

 from the pressure of the surrounding muscles during 

 their contraction. The text-figure 3 shows such a capsule and its cavity which has 

 harboured the larva, as well as the bored canal through which it has escaped; also 

 some other canals half contracted appear distinetly. 



The encysted larva measures about 1 mm. in length, most frequently somewhat 

 less, varying conspieuously in size; the smallest one found had a length of 792 ti, 



4 



Fig. 3. 



