FILARIA MEDINENSIS. 399 



ordinary temperature, dried up, and moved again when moistened. 

 The body is rather flat than cylindrical, 0755 mill, in length, 

 0026 in breadth, and 0019 in thickness. The head, 0010 mill, 

 in breadth, is narrowed; the mouth exhibits thin, small, round 

 warts, which are scarcely visible at this period of existence (as 

 they are also represented by Birkmeyer, so that it is questionable 

 whether we can speak, with Diesing, of four warts). Behind the 

 mouth the body becomes enlarged, and diminishes gradually pos- 

 teriorly, until it forms a distinct tail, 0250 mill, long, very finely 

 pointed, contractile, very flexible, but not curled, and very different 

 from that of the adult individual, in which it is 1 centim. in length. 

 After death, this tail quickly bends round at the level of the anus. 



The whole surface of the worm and its tail exhibit the well- 

 known fine rings, placed at a uniform distance (about 0003 mill.) 

 apart. The thickness of the walls of the body is 0*007 mill., and 

 surrounds the digestive apparatus. The substance of the body is 

 homogeneous, finely granulated, and exhibits no trace of mus- 

 cular fibres. The thick-walled, contractile, and rather straight 

 oesophagus, which is rarely beset with varicose enlargements, and 

 measures 0T79 — 0-183 mill, in length, does not entirely fill the 

 substance of the body, although it appears to do so, and the in- 

 testine does not adhere to the walls of the body, but between it 

 and the latter there are fine, fatty granulations, floating freely. 



The true intestinal canal originates from the cardia, where it 

 is rather more inflated than the cardia, and is, throughout, like 

 the body, somewhat flat. The substance of its wall is homo- 

 geneous, without striae or fibres, but sprinkled with numerous 

 granulations. From the cardia to the anus its length is 

 0-284 — 0-288 mill., whilst the whole length of the alimentary 

 canal, from the mouth to the anus amounts to 0-463 — 

 0-467 mill. Behind the anus the intestine is produced into a 

 small, pale, very contractile caecum of 003 mill, in length, into 

 which, however, the contents of the intestine do not enter, and 

 which is followed by another portion of the body of the length of 

 several hundredths of a millimeter, which contains a colourless 

 fluid. The anus is transverse, 0-006 — 7 mill, in breadth, sur- 

 rounded -by a little ridge, or a prominent contractile lip, and 

 allows the intestinal mass to escape. 1 



The worm is indigenous only in the hot zone, and even when 

 it is transported into colder climates, docs not appear to propa- 

 [' See also Busk in ' Transactions of Microscopical Society.' — Trans.] 



