1922] SEARS—TARAXACUM 325 
Fic. 19.—P.M.C. at metaphase, sequence A, showing narrow heterotypic 
spindle. 
Fic. 20.—P.M.C. showing heterotypic anaphase of sequence A. 
Fic. 21a, b.—Complementary sections of E.S.M.C. anaphase, masked but 
doubtless sequence A. 
IG. 22.—Second, true homotypic metaphase of sequence A in P.M.C., 
showing thirteen chromosomes at plate. 
I 
3-—P.M.C. orientation in sequence B, pairing somewhat delayed; 
nuclear iashiune disappearing. 
G. 24.—P.M.C. showing beginnings of delayed synaptic pairing in 
sequence B; membrane quite gone (cf. fig. 16). 
Fics. 25, 26.—Two different E.S.M.C.’s somewhat further along than 
fig. 24; such stages grade insensibly into sequence C. 
.C. showing wide metaphase spindle sogsnaapassns of 
sequence B 
Fic. 28.—E.S.M.C. in ameiotic metaphase of sequence B; synaptic 
mates end to end, perpendicular to spindle axis, giving quantitative division 
along We of prophase split. 
G. 29.—Telophase of first E.S.M.C. division, probably sequence B. 
Fr Ics. 30a, b.—Second division, purely somatic, following ameiosis in 
E.S.M.C; note breakdown of apical daughter and presence of about twenty- 
six homogeneous segments. 
Fic. 31.—Portion of P.M.C. showing disturbance in orientation due to 
ape elongation of nucleus; beginning of sequence 
IG. 32.—Similar pe fartlier along; pairing shnat complete, but 
spindle tc (cf. fig. 
Fic. 33.—P.M.C. in sequence C, synapsis virtually complete but chromo- 
somes sulle sequestered at poles without orientation or metaphase. 
Fic. 34.—P.M.C. in sequence C, chromosomes sequestered with little or 
no synapsis. 
Fic. 35.—P.M.C. in irregular telophase, probably of sequence C, showing 
organization of small supernumerary nuclei 
IG. 36.—E.S.M.C., late sepeataiion stage to show gradation into 
sequence D or amitosis. 
Fic. 37.—E.S.M.C. showing beginnings of nuclear elongation during late 
segmentation. 
Fic. 38.—The same, showing persistence of internodes between X-shaped 
chromosomes and origin of latter by persistence of prophase split. 
GS. 39a, b.—Complementary E.S.M.C. sections, showing more than 
twenty split chromosomes 
Fic. 40.—Beginning amitotic division (sequence D) in P.M.C. 
1G. 41.—Amitotic constriction of sequence D in E.S.M.C.; note 
chromosome form 
IG. 42 Atkeatiotic irregularities in P.M.C., showing also chromatin 
extrusion 
