ANNELIDA. 
597 
to accept. From Phyllodocea he removes Alciope, to constitute 
a distinct family including this genus and Liocape of Costa. 
Both Claparede and Eulers notice at much length the exten- 
sive family of Syllidm, whose numerous genera and species have 
tended not a little to perplex zoologists. Moreover agamogene- 
sis, accompanied by polymorphism, has been proved to occur i 
several of these Annelids, the males and females of whieh differ 
alike from one another and the sexless forms. Claparede thinks 
it quite useless to introduce generic terms to designate the 
sexual individuals. The names Polybostrichus, CErsted ( = Diplo- 
cercea^ Glr.), and Sacconereis, J. Miill., had acquired their right 
of citizenship before they were applied to the male sexual indi- 
viduals and females of Autolytus. Thus considered, they 
should be retained, more especially as, in the genus Autolytus, 
the sexual individuals (above all, the males) frequently differ 
more from the agamic individuals than in the other genera. 
But it seems superfluous to devise new terms, as Tetraglene 
(Gr.), for sexual forms whose agamic origin [Byllis) is known. 
If a name were wanting for these individuals, that of loida 
(Johnston) would have the priority. 
The fact that some SyllidcB are gamogenetic and others 
agamogenetic does not, according to Claparede, afford a fit basis 
for generic distinction. Generic and specific characters archest 
drawn from the sexless forms. The sexual individuals have a 
more simple intestinal canal, possess neither proboscis nor 
proventriculus, and their segments are often, perhaps always, 
provided with long hair-like setae, not found on the protozooids. 
Claparede entirely agrees with Krohn in considering that 
some of the agamogenetic Syllida give rise, by true gemmation, 
to sexual zooids, which originate between the last and penulti- 
mate segments [Autolytus^, Myrianida). In most, however, 
sexual elements are formed in the posterior region of the body, 
including numerous segments. These afterwards separate from 
the anterior region by fission. 
Claparede gives a synoptical table of the Europeai genera of 
P>yllid(B which he has himself observed, thirteen in number. 
In his brief diagnoses of these, he relies much on characters 
drawn from the pharyngeal armature, the value of which her 
further points out in the text. On tlie affinities of the exotic 
forms he does not venture to pronounce. 
Ehlers, on the other hand, takes up the entire group of 
Syllklce; and his investigations derive additional importance 
from the circumstance that they ai’e quite independent of those 
* See also a paper by A. Agassiz, On alternate generation in Annelids, 
and the embryology of Autolytus cornutus.'’ Bost. Journ. of Nat. Hist, vok 
vii. No. III. 1862 (pp. 384-409, with 3 plates). 
