SPIKOPTERA HOMIN1S. 443 



half-way between the extremities and the middle part, where the body is 

 contracted and abruptly bent upon itself. Some are irregularly trigonal, 

 others tetragonal. In the three-sided specimens one surface is broad, 

 convex, and smooth ; the other two are narrow and concave, and separated 

 by a narrow longitudinal groove, in which is sometimes lodged a filamen- 

 tary brown concretion. In the tetragonal portions the broad smooth 

 surface is divided into two parts by the rising of the middle part of the 

 convexity into an angle. The most remarkable appearance in these am- 

 biguous productions is the beautiful crenation of one of the angles or 

 ridges between the convex and concave facet ; which, from its regularity 

 and constancy, can hardly be accounted for on the theory of their nature 

 and origin suggested by Rudolph i : ' lymphamque in canalibus fistulosis 

 coactarn passimque compressam filum insequale efformare crediderim.' On 

 the other hand it is equally difficult to form any satisfactory notion of 

 these substances as organized bodies growing by an inherent and indepen- 

 dent vitality. We have not been able to observe a single example in 

 which the substance had both extremities well denned and unbroken ; 

 these, on the contrary, are flattened, membranous, and more or less jagged 

 and irregular. They present no trace of alimentary or generative orifices 

 on any part of their exterior surface, nor any canals subservient to those 

 functions, in the interior parenchyma. If subsequent observations on 

 recently expelled specimens of these most curious and interesting produc- 

 tions should, however, establish their claims to be regarded as Entozoa, 

 they will probably rank as a simple form of Sterelmintha, 



" The existence of the Spiroptera Jiominis is founded on the observation 

 of substances very different from the preceding productions. The speci- 

 mens so called were transmitted to Rudolphi. in a separate phial, at the 

 same time with the ova and larger parenchymatous bodies above described, 

 and are presumed to have been expelled from the same female under the 

 same circumstances. They consisted of six small Nematoid worms of dif- 

 ferent sexes ; the males were eight, the females ten lines in length, slender, 

 white, highly elastic. 



" The head truncated, and with one or two papillae ; the mouth orbi- 

 cular, the body attenuated at both extremities, but especially anteriorly. 

 The tail in the female thicker, and with a short obtuse apex ; that of the 

 male more slender, and emitting a small mesial tubulus, probably the 

 sheath of the penis : a dermal aliform production near the same extremity 

 determines the reference of this Entozoon to the genus Spiroptera. 



" There are no specimens of this Entozoon among the substances dis- 

 charged from the urethra of the female, whose case is above alluded to, 

 which are preserved in the Museum of the College of Surgeons." 



