TYPE ARACHNID A. 459 



single pair leading into trachese ; many forms parasitic ; fre- 

 quently with complicated metamorphoses. 



Nonparasitic, or parasitic only in larval stage ; terrestrial. Ori- 

 bates, Nothrus, Trombidium. 



Aquatic. Hydrachna, Atax. 



Living on organic matter. Tyroglyphus. 



Parasitic on animals. Bemodex, Sarcoptes, Bermaleichus, Anal- 

 ges, QamasiLS, Ixodes. 



Parasitic on plants. Tetranyohus, Phytoptus. 



LITERATURE. 



GENERAL. 



H. Grenacher. Untersuchungen uber das Sehorgan der Arthropoden. Gottingen, 

 1879. 



E. E. Lankester. Limulus an Arachnoid. Quarterly Journ. Microscop. Sci- 

 ence, XXI, 1881. 



J. Macleod. Recherches sur la structure et la signification de Vappareil respira- 

 toire des Arachnides. Archives de Biologie, v, 1884. 



R. Sturany. Die Coxaldriisen der Arachtioiden. Arbeiten a. d. Zoolog. Inst. 

 Wien, IX, 1891. 



J. S. Kingsley. The Embryology of Limulus. Part II. Journ. of Mor- 

 phology, Till, 1893. 



SCOEPIONIDA. 



L. Dufour. Histoire anatomique et physiologique des Scorpions. Memoirs 

 Acad. Sciences. Paris, xiv, 1856. 



E. E. Lankester. On the Coxal Glands of Scorpio, etc., and the Brick-red 

 Glands of Limulus. Proceedings of the Royal Society, xxxiv, 1884. 



G. H. Parker. The Eyes in Scorpions. Bulletin of the Museum of Compar- 

 ative Zoology, XIII, 1879. 



W. Patten. The Origin of Vertebrates from Arachnoids. Quarterly Journal 

 of Microscop. Science, xxxi, 1890. 



M. Laurie. TJie Embryology of a Scorpion {Euscorpius italicus). Quarterly 

 Journ. Microscop. Science, xxxi, 1890. 



PSEUDOSCORPIONIDA. 



A. Croneberg. Beitrag zur Kenntniss des Baues der Pseudoscorpione. Bulletin 

 Soc. Imp. I^aturalistes Moscou, n, 1888. 



SOLIPUG^. 



L. Dufour. Anatomic, physiologic, et liistoire naturelle des Oaleodes. Me- 

 moires Acad. Sciences, Paris, xvii, 1858. 



PHALANGIDA. 



E. BBssler. Beitrdge zur Anatomie der Phalangiden. Zeitschrift filr 

 ■wisscnsch. Zool., xxxvr, 1883. 



