574 
V. Faussek, 
at this Stage, that the gland seems almost solid. In the abdomen also all the 
coelomic cavities disappear except the unpaired one in the caudal lobe, which, 
inexplicable as it may seem, remains as the stercoral pocket . . (S. 294). 
. . . Das Proctodäum tritt erst später mit ihr in Verbindung; dabei ist es 
von innen von einer Cuticula bekleidet, während letztere in der Rectalblase fehlt, 
was, seiner Meinung nach, die von Proctodäum unabhängige Entstehung der 
Rectalblase bestätigt. Die Entstehung der MAiPiGHischen Gefäße ist unauf- 
geklärt geblieben. Des Verfassers Meinung ist die, daß die Gefäße weder aus 
dem Proctodäum, noch aus den Auswüchsen der Rectalblase entstehen. Wahr- 
scheinlich werden sie aus den mesodermalen Zellen der Abdominalsomiten ge- 
bildet, die Gefäße treten zuerst als ein Paar von festen Mesodermstreifen auf. In 1 
einer späteren Arbeit von Kishinoye (1894) werden die Cölomhöhlenbildung und 
deren Bestimmung ausführlich behandelt. Im Stadium der größten Krümmung 
des Embryos auf die dorsale Seite (wenn das Ei vom Embryo am stärksten um- ’ 
wachsen ist) sind die Mesodermalsomiten des Abdomens am besten entwickelt: 1 
“in the abdomen, the growth of the mesodermic somites, except that of the i 
first abdominal segment, is enormous, extending rapidly towards the dorsal median j 
line. Thus, in the abdomen, the dorsal portion of the coelomic cavities develops j 
rapidly, whith their ventral portion as well as the portion which enters into the I 
appendage remains only slightly developed. In the cephalothorax, on the j 
contrary, the portion of the coelomic cavities which enters into the appendage i 
develops rapidly, while their ventral and dorsal portions remain undeveloped” 
(S. 290). Die unpaarige Höhle im Mesoderm des Schwanzlappens wird, im Ver- | 
gleich mit den Angaben der ersten Arbeit, später gebildet. “A cavity is produced j 
in the tail lobe. It is unpaired. The unpaired cavity thus made cannot be con- i 
ceived otherwise than as a homologue of the coelomic cavity. Though the cavity I 
is certainly not formed by an invagination, I thought that the cells in the tail I 
lobe might be produced by the proliferation of the ectoderm. But I found that j 
the cells enclosing the unpaired cavity are the remnant of the mesoderm cells | 
which gave rise to the mesodermic somites of many preceeding Segments and that j 
they are entirely separate from the ectoderm. Previous authors who have studied j 
the development of the spider, overlooked this cavity in the mesoderm of the j 
caudal lobe, and observing the stage at which the unpaired cavity communicates ! 
with the proctodaeum, consider the former as a portion of the latter. If the cells | 
enclosing the unpaired cavity are ectodermic in origin, the numerous mesoderm [ 
cells in the caudal lobe must disappear all at once, as there are no cells in the 1 
lobe except those surrounding the last fused pair of coelomic cavities. But the | 
disappearance of many cells ot once is quite impossible.” Etwas ausführlicher j 
behandelt der Verfasser, in welcher Weise die Fusion und die Zerstörung der i 
Cölomhöhlen, welche “degenerate and disappear” verläuft, “the greater portion I 
of the coelomic cavities of the four ambulatory appendages degenerates, the | 
mesoderm cells forming their wall becoming gradually changed into muscles”. i 
Auch im Abdomen findet die Fusion und Zerstörung der Cölomhöhlen statt, so [ 
daß zu der Zeit, wo der Embryo seine definitive Struktur erhält “the coelomic j 
cavities undergo great changes. In the cephalothorax, they all disappear^ except i 
the small portions at the outer bases of the first to third ambulatory legs. These 
remnants fuse together and form the coxal gland. The lumen or the coelomic | 
cavity of the gland is so small at this stage, that the gland seems almost solid, j 
I 
I 
