AOANTHOOEPHALA 259 



K. Zeitsch./ 1829. Idem, " Nuovo genere," &c., in ' Gaz. 

 Med. Lombard/ 1849. Grille, <Fam. d. Annelid./ s. 109. 

 Hofmeister,m ' Burmeister's Zeitung fur Zool./ 1848. Johnson, 

 ' Treatise on the Medicinal Leech/ Leuckart, 1. c., Bd. ii, 

 s. 634-739 (with many refs.) Ley dig (" Anat."), ' S. und K. 

 Zeitsch./ Bd. i. Moquin-Tandon, ' Monogr. de la fam. des 

 Hirudinees/ 1846. Idem,, in his ' Medical Zoology ' (Hulme's 

 edit.), 1861, p. 137. Muller, F., in ' Archiv f. Naturg./ 1846. 

 Pereira, in his ' Materia Med./ vol. ii, p. 2197, 1853. 

 Savigny, ' Descript. de TEgypte/ 2nd edit. Idem, ' Syst. des 

 Annelides/ 1820Schmarda, 'Neue wirbell. Thiere/ Bd. i 

 (quoted by Leuckart). Virey (and Serullas), in ' Journ. Pharm./ 

 1829, p. 614,,Wagener, in ' Troschel's Archiv/ 1858, Bd, i, 

 s. 244 et seq. Wahlberg, in ' CEfvers. Kongl. Yetensk. Akad. 

 Forhand./ Stockholm, 1855. 



SECTION IV. PART III. AEACHNIDA (Pentastomes, Mites, 



Ticks). 



The Trachearian division of the Arachnida comprises a few- 

 internal parasites that attack man, and many ectozoa which are 

 parasitic upon man and animals. The species can only be 

 noticed very briefly. 



Pentastoma tcenioides, Rudolphi. In the system of classifica- 

 tion adopted by Diesing, this entozoon and its allies are placed 

 in the division Geplialocotyleen and therefore, in association 

 with the Cestodes, with which, however, it has no structural 

 affinity. It was long ago pointed out by Van Beneden, T. D. 

 Schubart, Leuckart, and others, that the pentastomes were 

 Acarine and Lernsean Arthropods; the genus being osculant 

 between the Acaridse and Lernaeadae. The whole subject is 

 discussed in Leuckart's profound memoir quoted below. 



The adult Pentastoma taenioides is characterised by the 

 possession of a vermiform, lancet-shaped body, flattened at the 

 ventral surface, attenuated posteriorly, and marked transversely 

 by about ninety rings (fig. 50, 1 and 2). The cephalo-thoracic 

 segments are continuous with the body, each supporting a pair 

 of strong retractile chitinous claws; four in all. The head is 

 truncated, furnished with an oval mouth, armed with a horny 

 lip. The integument of the body is perforated with numerous 

 respiratory openings or stigmata. These are wanting in the 



