TYPE ARACHNIDA. 



455 



The mid-gut usually sends off a number of csecal diverticula 

 which may branch at the ends, and Malpighian vessels, 

 sometimes one, sometimes a pair, and sometimes many are 

 usually present, while in addition, in some forms, a rectal 

 bladder, similar to that occurring in the Aranese, is found. 



M"d 



an 



Fie. 209. MALE OF Gamasiis tergipes (after WINKLER). 



an = anus. st = stigma. 



<xe = caecal pouches of intestine. stc = stigma-canal. 



go = genital orifice. T = testis. 



Md = chelicera. t = tongue. 



mg = Malpighian tubules. Vd = vas deferens. 



Mxp = pedipalps. I-IV - limbs. 



The nervous system, as might be supposed from the con- 

 centration of the body regions, is composed of a supraoesoph- 

 geal syncerebrurn and a larger suboesophageal gangliouic 

 mass from which numerous nerves are given off. Eyes are 

 usually wanting, or may be present in the form of one 

 (Ixodes) or two pairs of small apparently simple ocelli. 



Coxal glands have been described as occurring at the 

 bases of the second pair of legs (Oribatidse). The repro- 



