HIRUDINEA S. DISCOPHORA 345 



3. Echinorhynchus moniliformis, Bremser, 1819. 



The male is 4 cm. in length, the female 8 cm. long. This species 

 lives in the intestine of field-mice, rats, marmots and Myoxus qucrcinus. 

 A beetle, Blaps mucronata, is the intermediary host. 



This species has also once been artificially cultivated in man (Grassi and 

 Calandruccio). 



LITERATURE. 



LAMBL, W. Micr. Unters. d. Darm-Excrete. (Prag. Vierteljahrsschft. f. pract. 



Hlkde., 1859, Ixi., p. 45.) 

 SCHNEIDER, A. Entw. d. Ech. gigas. (Stzgsb. d. oberh. Ges. f. Natur- u. Hlkde., 



1871, p. i.) 



LEUCKART, R. Commentatio de statu embryonal! et larv. Echinorh. . . . Lipsiae, 1873. 

 KAISER, J. Ueber die Entw. d. Ech. gigas. (Zool. Anz., 1887, x., p. 414.) 

 GRASSI, B., and CALANDRUCCIO. Ueb. einen Ech., der auch im Menschen parasitirt. 



. . . . (C. f. B. u. P., 1888, iii., p. 521.) 



HAMANN, O. Die Nemathelminthen. I. Monogr. d. Acanthoceph. Jena, 1891. 

 STILES, C. W. Sur 1'hote intermediaire de 1'Ech. gig. en Amerique. (C. R. soc. 



biol., Paris, 1891 [9], iii., p. 764.) 



KAISER, J. E. *Die Acanthocepha lenund ihre Entwickelung. Cassel, 1893. (Bibl. 

 zoologica, vii.) 



E. HIRUDINEA s. DISCOPHORA, Leech. 



The Hirudinea, which have been appropriately included amongst the 

 annelida, differ in many respects from the typical members of the group ; 

 their body is long and flat, it lacks the pai^rjpdia that are characteristic 

 to all forms of aqjoelida ; but, on the other hand, possesses a terminal 

 posterior sucker, and in many species there is also an anterior sucker. 

 The mouth is terminal at the anterior end, the anus lies dorsally above the 

 posterior sucker (fig. 226). The body is segmented, but this is less mani- 

 fest in the body covering than it is in the arrangement of the internal 

 organs ; the segmentation, nevertheless, is also indicated exteriorly by the 

 appearance of the cutaneous sensory organs which correspond to the seg- 

 ments. This shows what the condition of the ganglia in the abdominal 

 ganglion chain has taught us, that the anterior and the most posterior 

 segments are considerably abbreviated a part of the latter taking part in 

 the formation of the suctorial organs. In a great many species the skin is 

 distinctly annulated, four or five of such rings, at least in the central region of 

 the body, appearing on one segment of the body. The condition of their 

 body cavity is another peculiarity of the Hirudinea ; it is narrowed by 

 the powerful development of the connective tissue and the muscular 

 system into four tubular sinuses, which have the appearance of blood-vessels. 

 There are usually one dorsal and one ventral median trunks, as well as two 

 lateral trunks ; in addition, a particular blood-vessel system exists. 



The skin consists of a very thin cuticle that is cast off from time to 

 time, it is secreted by the underlying cylindrical epithelium, which contains 

 numerous goblet cells. The muscular' system is strongly developed ; it consists 

 of long tubular fibres, which run circularly, longitudinally and in the 



