284 
Graber,* in his last more elaborate and carefully considered work, 
however, refers more at length to Tichomiroff’s memoir on the silk- 
worm, and quotes from him as follows: ‘* Wood-cut 26 represents 
the stage in which two new structures become apparent, namely, 
first, seven pairs of spiracles (from the second to the eighth ab- 
dominal segment), and, second, the ventral legs. The last become 
visible on all the segments, except the first. As regards the last 
ones, I could not satisfy myself that they, as those Kowalevsky refers 
to in Hydrophilus, arise out of a common germ with the outgrowth 
bearing the stigmata. This outgrowth arises much later.’’ 
He adds further on (p. 42): ‘* Zhe ventral legs, which originally 
appear on all the abdominal segments, with the exception of the 
first, exist in their complete number only a short time. Five pairs of 
them, namely those which belong to the third, fourth, fifth, sixth 
and ninth segments, begin to develop rapidly, whzle the others 
very imperceptibly disappear in the mass of the primitive hypodermis” 
_ (Stammhypodermis). 
On the other hand, in Bombyx mori, Selvaticot neither mentions 
nor figures these deciduous organs. With these facts before him, 
Graber concludes that the question of the presence or absence of a 
continuous series of abdominal appendages in view of the extraor- 
dinarily short and transitory development of these embryonic struc- 
tures cannot be answered yes or no, and that the question whether 
these processes correspond to true appendages, to primary or second- 
ary appendages, cannot in the present state of our knowledge 
be solved. He then goes on to state that in the embryo of Bom- 
byx mort (in all the abdominal segments except the ninth and tenth) 
faintly marked knob-like elevations are to be seen which may yet 
(zmmerhin) be considered as the first indications of rudimentary ap- 
pendages (see his Fig. 108). He adds that ‘‘they are much 
fainter and are also less sharply defined than those figured by 
Tichomiroff in wood-cut 26, although on the whole a return to the 
view of the observer mentioned would be in accord with the 
truth.’’{ In a word, the observations and figures of Graber appear 
to confirm the text and figure of Tichomiroff, which we therefore 
* Vergleichende Studien am Keimstreif der Insecten, von Vitus Graber, Wien, 1890. 
+ Sullo sviluppo embrionale dei Bombicini. Annuario della r. stazione bacologica di 
Padova, 1882. 
{ This is a clumsy translation of Graber’s rather guarded endorsement of the correctness 
of Tichomiroff’s observations, his expression being: ‘‘Obwohl sonst die betreffende 
Wiedergabe seitens des genannten Forschers der Wirklichkeit sehr nahe kommt.’’ 
