A. W. Wright— Forms of the Electrical Dischanje in Air. 437 



hog drags the hind quarters along the ground fi'om place to 

 place in search of his food, although it is by no means proven 

 that the worm is the real cause, unless we be able to demon- 

 strate its existence in some cerebro-spinal center, or some point 

 more likely to destroy the reflex power in the cord itself. 



Structure. — The head and oral cavity are alike in male and fe- 

 male. The oral cavity is rather oval than round, and is sur- 

 rounded by a hexagonal frame, each corner having a papilla 

 and hooklet, while each side is armed with six serrate teeth. 



Looking into the oral cavity, it is funnel-shaped, having 

 three openings at the back, one of which connects directly 

 with the oesophagus, wbile the others appear to connect with the 

 water vessels. 



The intestine is long and contains some pigment granules, 

 arranged in dendritic forms, throughout its length ; the whole 

 is thrown into convolutions, and gives an almost black appear- 

 ance to the worm, except when the white oviducts distended 

 with eggs, or the seminial vessels of the male are folded over 

 the intestine, when it has a white, mottled appearance. 



The caudal extremity of the female is spindle-shaped, but 

 has two little bursas higher up. In the male it is formed by 

 three-lobed bursae, above which are two well developed flexible 

 spi ula. 



Abt. LXIV.— Oto certain Forms of the Electrical Discharge in Air; 

 by Prof. Aethur W. Wright, Williams College. 



Lv a paper published in this Journal, May, 1870, the writer 

 descnbed a peculiar form of discharge between the poles of the 

 ^oltz electrical machine, worked at high tension, and without 

 condensers. A non-luminous discharge was observed to take 

 place over a considerable interval, with the production of a jet 

 or brush upon the negative, and a glow upon the positive ball, 

 ^d the formation in this glow of shadow-like images of objects 

 placed between the poles. It was shown also that the discharge 

 passed over lines having a definite form, and that they were 

 curved so as to form arcs issuing normally from the surfaces of 

 thepoles.* ^ 



^en the condensers are employed the dark discharge also 

 ^c^ under certain circumstances, and exercises an important 



\^:^discurgrw.z:i:kr^:x 



iisi-}^l'Zr^ "t""^ curved lines, as was indicated by certain i 

 j;^^e. (Exper. Res., 1 



