318 SUMMAEY OF CURRENT RESEARCHES RELATING TO 



numbered in series. The sheet that carries the chart may also carry 

 a series of printed numbers with corresponding spaces for records. 

 (See fig. 1.) Where the objects belong to a few great groups, such as 

 land-inhabiting, fresh-water, and marine, the printing of the blank 

 sheets in correspondingly assorted colours is an advantage. 



The chart is made by using a camera lucida and an objective of 

 about 5-in. focus.* In order to reduce the magnification, the objective 

 may be screwed into the end of the draw-tube of the microscope barrel. 



jjOi 7 3Doryl. styraatuxus - 28 l' . v 



1,11 4Aoli?oniaclora. bra.zU _ 29 '.' . '.' \ . 



5Horyl.. .caudatua?_ . 30 Mononchua minor- - -i 



6ElaBspnem& .- ,two_ . 31 '.' . fragment alaM - 



6, J ©TylenchuB, p^rjfactua SSRhatditlK 



K e. ' '*■ *■ * SDoryl. additl.cius . 33YjDpryl..pxo,tru4ea6. 



^ ^^'^ :>i j^ 9 " protrudens 34 See 11 



r -,-^-— --,.— u 10 .". .'. ..".... 35^1 Poryi.. . ; . . . 



-^' 7* ^"' -'s c -^ 14 - '^ - 36Aohromadora. .... 



£y *)it \' "• ^ +^Troplconeoia. t.enjJlcoiaeSTsee.ll 



7^ ^/S. %x ''*" ^ M^^®-'"'^ -^^^ ... - SSRhabditis. . . , . . 



, ; ^. ... i^ 14Achromadora-p.ap.illae?39Elas8Dnfima . . . *. 



^5^ "a C* li V iBPitre 40 Y. BoryL. . . . ^ .• 



«i w/ 4.* l6Mqnonchu8 41 See. 11 ....... 



•srC<'"'^ 'hr^ *VJ4i 17Achromadora .... 42 pure - 



--.-'?.& ISRhatditjls. ..... 43See.ll . ^ - - 



•??\ %i ^* IQlrof'^.s ...,-.... 44Doryl.. po.or. ^ . , 1. 



20Elassoiiema .... 45 Rbabditia. ...... 



21 . .!' ,. 46 . . ". 



22Rhai)d.itjls. 47 Doryl. al. -tl-. - - - 



^ Tylen.oh.ug. ^ .2 



24 Monon_ohus_ minor . . ftBDerylj mX.. Bgga . . 

 25RJiatdit_ls] __ ...50 



Fig. 1. — Record chart used in tabulating large numbers of micro- 

 scopic objects arranged on a series of slides. As printed the chart 

 was 5 in. by 8 in., and carried only the two columns of figures 1 to 50 

 inclusive. At the left is seen the camera lucida drawing, or chart, 

 recording the form, size, and relative position of forty-nine micro- 

 scopic objects — in this particular case, nemas. Immediately above 

 the chart are seen the data relating to the particular slide charted, 

 which was No. 7 in a series of eleven slides (1-11), and which carried 

 a collection of forty-nine nemas gathered from soil attached to the 

 roots of plants imported from Brazil. Names and other notes with 

 regard to the nemas were typewritten opposite the appropriate 

 numbers. Nos. 2, 7, 12, 13, 14, 23, 48 and 49 were encircled to 

 indicate that these specimens were of especial interest. One-half 

 size. 



A low power eye-piece is used with the objective, so that all the objects 

 on the slide can be seen at one time. A chart having a magnification 

 of five diameters is of convenient size. The suitable illumination is 

 secured by using a concave mirror without sub-stage condenser. The 

 light may be direct, in which case the objects are seen as dark bodies 

 on a light background, or a dark-ground effect can be produced by 

 insertiug between the concave mirror and the objects a small opaque 

 disc. A suitable disc may be made by stripping the barbules from a 



* A very strongly magnifying spectacle lens will serve the purpose. 



