52 ANIMAL PAKASITES. 



3 a. Sarcoptes Equi (figs. 1 and 2). The males of this pretty 

 large species, which is visible with the naked eye, are about ^" 

 in length and breadth, resembling a square, notched at its four 

 angles ; arched on the back and belly, tolerably thick ; the body 

 covered with alternate furrows and raised lines, running trans- 

 versely on the back and on the abdomen in a semicircular form, 

 or even longitudinally, by which the skin acquires the appearance 

 of shagreened leather (like morocco leather). 



Fig. 1. 



a, the head ; I &, the anterior feet ; e c, the sucking disc or sucking lamina on the 

 last joint ; e e, the outer,//; the inner posterior feet. 



On the back we see some small tubercles, and towards the 

 front a long, stiff hair. On each side of the body, at the com- 

 mencement of its posterior third, there also stand a long and a 

 short hair. According to Raspail and Hertwig there only ap- 

 pears to be a chitinous framework for the two anterior pairs of 

 feet, at least it is not referred to for the posterior feet. 



The head is conical or proboscidiform ; its length is one third 

 of that of the body, and its thickness not very considerable. 

 Above the proboscis, two nipper-like moveable spines lie horizon- 

 tally and close together. Between the proboscis and the spines, 

 a very thin, capillary organ sometimes projects. Close to the 

 origin of the spines, there is on each side a fine, stiff hair ; 

 behind this a second ; and then a round point, with a dark out- 



