298 
POPULAR SCIENCE REVIEW. 
having a rigid acicular body, bas been recently discovered by 
0. Biitscbli within tbe intestine of tbe Hematoid worm, Trilobus 
gracilis. A social gronp of tbis species, bearing tbe accompanying 
title of Rhaphimonas Butschli, is represented in PI. VII. fig. 12. 
Among tbe simpler forms of tbe Flagellata that are notable 
for their parasitic mode of existence, a prominent position must 
be allotted to tbe numerous representatives of tbe genus Bodo. 
Hitherto made to include a very heterogeneous assemblage of 
flagellate types, tbis generic group, as recognized by tbe 
present writer, comprises only those species which, while 
agreeing with Cercomonas in tbe possession of two flagella, 
the one anteriorly and the other posteriorly inserted, dif- 
fer, independently of tbeir separate habitats, in tbe cir- 
cumstance, that tbe posterior flagellum is adhesive, and 
utilized for tbe purpose of anchoring tbe animalcule to tbe 
surface of contiguous objects ; while in Cercomonas tbis 
appendage is non-adbesive and simply trailing. Under tbe 
conditions above named, tbe endoparasitic Bodos are mostly 
found adhering in more or less considerable social groups to 
tbe intestinal walls of tbeir respective hosts, but are at tbe 
same time readily detached, and accommodate themselves for 
awhile to a natatory existence. Familiar examples of tbis 
genus are afforded by tbe Bodo ranarum of Ebrenberg, in- 
habiting tbe intestines of tbe common Frog ; and by B. helicis, B. 
julidis , and B. melolouthce, of Prof. Leidy, originally referred 
to tbe genus Cercomonas , and inhabiting respectively tbe 
alimentary tract of an American garden-snail, centipede, 
and cockchafer. Two forms, Bodo hominis of Davaine, and 
B. urinarius of Hunter, attach themselves to tbe human 
subject ; while tbe B. lymncei of Stiebel is similarly entertained 
by tbe common pond- snail. An illustration of a typical 
representative of tbe genus Bodo, B. intestinalis , will be found 
at PL VII. fig. 13. 
Ho apparently moutbless forms possessing two anteriorly 
inserted vibratile flagella only, and thus referable to tbe 
Dimastigous section of tbe Flagellata- Pan tostomata, have 
as yet been recorded as leading an exclusively endoparasitic 
existence. That division of tbe same section, however, which 
is distinguished by tbe possession of more than two flagelliferous 
appendages, and which may thus be conveniently distinguished 
by tbe title of tbe Pantostomata-Polymastiga comprises several 
highly noteworthy forms. First among these may be men- 
tioned tbe several remarkable species for which Dujardin 
instituted tbe generic title of Trichomonas , and which were 
originally described by that investigator as possessing, in 
addition to two or three flagella, a more or less conspicuously 
developed fringe of vibratile cilia. It bas been recently shown by 
