, C 
H and
H CO (ortho and para) in the protoplanetary disks of DM Tau and GG
Tau. For the first time organic molecules are observed in objects
representative of the presolar nebula. These molecules are
underabundant with respect to the standard dense clouds. The
depletions in the ``outer'' disk of DM Tau (100<r<900 AU), derived
from the line intensities and state of excitation, range from 
(for CO) to 100 (for H CO). The relatively large abundances of
CN and C H are typical of a photon-dominated chemistry
(Figs. 1, 2).
Accepted for publications in A&A 317, L2
Figure: Line profiles observed toward GGTau.
Integration time (on + off) is 4-8 h for each spectrum.
Double-peaked profiles are observed for H CO 3 
-2 
and
CS 3-2 and 5-4. They agree in position and width with the CO line
profiles. Hyperfine components of HCN and CN are indicated.
Figure: Same as Fig. 1, for DMTau.