STRUCTURE AND DEVELOPMENT OF LOXOSOMA. 269 
been considered to form a part of the generative apparatus. 
According to Nitsche, there exists in the bud, lying trans- 
versely across the intestine, on its oral side, a dumb-bell 
shaped mass (1. c., Taf. xxv, fig 19, GA ) which Nitsche does 
“ not hesitate to identify as the rudiment of the generative 
organs.” The same structure may be observed in the adult, 
and is represented in (Nitsche’s) Taf. xxv, fig. 5, GA. This 
“generative rudiment” has been figured by Schmidt as the 
“testes” in L. Raja 1 (Taf. i, fig. 1, t), whilst Salensky, in his 
fig. 3 of PI. xii, has lettered the same organ gs., without 
explaining the meaning of these letters; from the text, how- 
ever, it seems obvious that the structure in question is con- 
sidered either a portion of the generative system, or some other 
form of gland. I have not the slightest doubt that the organ 
so consistently described by the above observers as a gonad 
is in reality the suboesophageal ganglion. The structure 
figured by Nitsche (No. 10, Taf. xxv, fig. 5, N), and con- 
sidered by him to be possibly nervous, I believe to have no 
existence as a special organ. Schmidt (20) has expressed his 
opinion that Salensky’s “ ganglion ” is really the empty vesicula 
seminalis, and with this view I entirely concur. Salensky has 
pointed out the difficulty of discovering the “ ganglion,” 
except in young individuals which have developed no genera- 
tive organs : in the adult one may assume that he recognised 
the true nature of the vesicula seminalis from the presence of 
the spermatozoa. Although Schmidt is right in denying the 
nervous nature of this supposed ganglion, his opinion that the 
large nerves figured by Salensky are also parts of the generative 
apparatus is erroneous; the existence of these nerves cannot be 
1 On p. 7 of No. 11, Schmidt says, “ Ich finde hei Loxosoma singulare 
oberhalb der Hoden, aber auch zwischen Oesophagus und Enddarm quer 
gelagert eine Art von Nervenband oder Doppelganglion, dessen Bedeutung mir 
aber desshalb sehr fraglich, weil ich bei den anderen Arten nichts Ent- 
sprechendes gesehen.” Schmidt has thus apparently really identified the 
ganglion in L. singulare, although, led astray by the belief that the same 
organ was a gonad in L. Raja and other species, he has failed to convince 
himself of the correctness of his own identification of the organ in L. 
singulare. 
