Cytology of the Asciis. 
54i 
Lachnea stercorea. 
The development of Lachnea stercorea was investigated by one of 
us (7) in 1907. A trichogyne and antheridium are present, but no longer 
functional, and, as in Humaria granulata^ the female nuclei fuse in pairs in 
the ascogonium. 
The nuclei of the ascus are not of great size, but the heterotype 
prophases are nevertheless remarkable for their clearness and delicacy. 
The first contraction takes place after the fusion in the ascus (Fig. 38), 
and is succeeded by the loosening out of a well-marked double spireme 
(Fig. 39) ; this subsequently draws itself up into about four loops (Figs. 40, 
41) in which the duplication of the chromatin thread may still be observed. 
Eventually four gemini separate (Fig. 42), contract (Fig. 43), and pass on 
to the spindle (Figs. 43, 44), where they undergo the usual separation into 
univalent chromosomes, and four of these pass to each pole (Fig. 45). 
It seems to us very clear that in Lachnea stercorea the loops of the 
heterotype prophase each represent a bivalent chromosome, and that 
the separation on the spindle takes place transversely. 
The homotype division is of the ordinary type ; the chromosomes are 
still four in number (Figs. 46, 47), and no ‘ contraction 5 phase has been 
observed to precede the appearance of the spindle. In the third metaphase 
four chromosomes are present (Fig. 48) ; they do not divide, and two only 
pass to each daughter-nucleus (Fig. 49). In these particulars brachymeiosis 
in Lachnea stercorea corresponds to the same process in H. rutilans (8), 
where also the double number of chromosomes is present throughout the 
second division and in the prophases of the third. 
In studying the ascus divisions of this species we frequently observed 
the occurrence of two long and two short loops in the early meiotic stages 
(Figs. 40, 41), and of two long and two short chromosomes in the later 
prophases (Figs. 42, 43), and in the heterotype spindle (Fig. 44). At this 
time the gemini, since the fusion in the ascus is complete, represent two 
sets of paired allelomorphs. Separation of those which came together in 
fertilization takes place in the first division, while the distribution of the 
allelomorphs of the asexual fusion is accomplished in brachymeiosis. In 
the telophase of the latter division (Fig. 49) a long and a short chromosome 
can, in favourable cases, be distinguished at the pole. 
We were not prepared to attach importance to any of these cases 
separately, but the frequent recurrence of the long and short chromo- 
somes, and of the long and short loops in the earlier meiotic stages 
seems tous not without significance. Moore and Arnold (14), investi- 
gating the meiotic phase in man and other animals, have found that the 
forms of the gemini are constant in all spermatocytes of a given species. 
Baumgartner (1) also in two species of cricket finds recurrent differences in 
