Thilo’s memoir on »Die Umbildungen an den Gliedmaßen der Fische«. 181 
that this ray has the same concave artieular face corresponding with 
the main articular face in Doras! (7 + n, Figg. 3 and 4). This articular 
face is apparently placed on the upper half of the ray (TuıLo’s 
Fig. 43). The process @ (»/sp«, ibid.) is somewhat more prominent 
in Salmo than in the Siluroidee; the process ? (»H«, ibid.) is small, 
yet distinctly visible The process 0 on the contrary is ab- 
solutely wanting. That it is also wanting in Malapterurus elec- 
tricus, whose 1° pectoral ray is not spinelike and cannot be fixed, has 
— strange to say — escaped the observation of Dr. TurLo, though 
he has also examined this genus of the Siluroide. From these facts 
it appears to me that, apart from the reasons set forth in 1 and 2, 
we may be justified in drawing the conclusion, that when the pro- 
cess 0 is found, where the ray is spinelike and subject to being 
fixed, but is wanting where this is not the case, then it must be 
this process that effects the fixation — and that when the process P 
is found in both cases, then it can be no »Hemmfortsatz«. But, as 
I have said, the reasons stated above (1 and 2) are direct proofs of 
the correctness of this conclusion. 
It is true that on Dr. Tuıto’s Fig. 43, representing the first 
pectoral ray of Salmo, there is placed a »K«. Now, as no Kegel 
(process 0) whatever is found there, it is to be supposed, that the 
place marked with »X«, in his opinion, corresponds morphologi- 
cally with the process 0 (the »Kegel«) in Synodontis and Silurus. 
But this is a mistake: More than 30 years ago Professor GEGENBAUR 
has very correctly acknowledged? that: »Das äußere Basale verliert 
seine Selbständigkeit, indem es vom Randstrahle des sekundären 
Flossenskelets umwachsen wird. Dadurch erklärt sich die Ein- 
lenkung dieses Strables an den Schultergiirtel.« To this 
Dr. TuıLo has not paid sufficient attention. For otherwise, he would 
not have failed to see that what carries the whole articular part in 
Salmo and the main articular part in Synodontis, Doras (y + 7, Figg. 3 
! In Salmo the form of the articular face differs very much, it is true, 
from that of the face (y + 7) in Doras and Synodontis; it does not differ much 
however from the form of the face in Platystoma and Plecostomus (y, in the 
Figg. 23 and 24 in my book) and in Silurus. 
2 These two processes are not, in Salmo, connected with other bones by 
diarthrosis but only by connective tissue. 
3 C. GEGENBAUR, Untersuchungen zur vergleichenden Anatomie der Wirbel- 
thiere. 2. Heft. 1. Schultergürtel der Wirbelthiere. 2. Brustflosse der Fische. 
Leipzig 1865. pag. 161. 
