326 
G. DEBAISIEIIX. 
mediate between tlie paternal and the maternal. These 
conclnsions were soon considered doubtful by Seeliger (’94) 
and i\[organ (’95), and very numerous experiments were again 
made on diti'erent material. In nearly all these experiments 
the student started with the idea of finding out if the hybrids 
had characters which were exclusively maternal, exclusively 
})aternal, or intermediate between the characters of the two 
parents. 
Driesch (’98) studied the crossings between Spheerechinus, 
Strongylocentrotus, Echinus and Arbacia, and he remarked 
that '‘Wahreud alle anderen untersncliten Charakteie der 
Bastardlarveu von Echiniden sicli als rein mutterlich und 
damit sehr wahrscheinlich als von der Natur des Eiplasmas 
abhangig erweisen, treten bei der Skeletbildung zuerst die 
Charaktere der vaterlichen species auf, indem sicli dieselben 
als eine Mischung vaterlicher und miitterlicher Eigenschaften, 
je nach der kombination mehr zum vater (Sph. $ x Echinus 
, Sph. ? X Str. ) oder mehr nach der Mutter (A. ? x 
E. J'jE. ? X A. d' ) hinneigend darstellt.” The same author, 
in a more recent work (’03), does not notice the transmission 
of pigmentary characteristics by the father, but relying on 
Boveri’s work, he considers that this transmission is sometimes 
possible, whereas Fischel’s experiments and conclusions 
(’06) prove a certain paternal influence and the heredity of the 
paternal characters. Other material was used by Vernon (’98). 
Housed eggs of Echinocardium cor datum and fertilised 
them by sperm of Echinus, Strongylocentrotus, Splimrechinus 
or Arbacia. The hybrids were all of the maternal type, but the 
aboral spike was considerably shorter in them than in the 
normal larvm. In a case where the opposite crossing was 
successful, Echinus $ x Echinocardium cJ , the characters 
of the hybrids were exclusively muternal. The same material 
was again experimented on by MacBride (’ll) and the results 
were quite different: whilst the crossing of Echinus ? x 
Echinocardium did not give larvae, the hybrids Echino- 
cardium $ X Echinus presented paternal and maternal 
characters. 
