Dr. R. Greeff on Autolytus prolifer. 175 
completely omitted both in the description and in the numerous 
figures. Claparéde, who also notices this defect, in his valu- 
able work on Annelides published in 1864*, has reestablished 
the genus Awutolytus as previously indicated by Krohn, and 
has also enriched our knowledge by three fine new species. 
Ehlers}, on the contrary, in his work on the Polycheta, has 
again treated our genus very unkindly, forming a new genus, 
Procerea (picta) of a worm which appears to be undoubtedly 
an Autolytus. That the dorsal cirri on the third body-segment 
are rather longer than on the following segments (which, 
moreover, occurs also in other representatives of Autolytus— 
for example, in A. scapularis, Clap.) cannot possibly suffice 
by itself for the establishment of a new genus; and yet this 
appears to be the only differentiating character, as in other 
respects, according to the excellent and careful description and 
figure, Procerwa picta in all its essential characters is a true 
Autolytus. Nor must Ehlers’s worm be separated from Auto- 
lytus merely because Ehlers observed no alternation of genera- 
tions in it. Without taking into consideration that the state- 
ments as to the sexual conditions in Procerwa are imperfect, 
even the ascertained absence of alternation of generations, 
such as Claparédet quite correctly establishes for his A. sca- 
pularts, would by no means of itself justify the establishment 
of a new genus. [I therefore think that I may propose to 
change Procerea picta provisionally into Autolytus pictus. 
Under the generic name Polybostrichus, Cirsted, already 
referred to, and the connexion of which with Autolytus has 
been described by Agassiz, Keferstein§ has likewise furnished 
valuable observations on the male bud of Avwtolytus, the iden- 
tity of which with Max Miiller’s Sacconere?s helgolandica he 
endeavours to demonstrate. It is remarkable, however, that 
in neither of his memoirs does he say a single syllable of the 
enetic connexion of Sacconereis and Polybostrichus with Auto- 
ytus, so definitely expressed by Agassiz and Krohn, but treats 
his Polybostrichus as a perfectly independent genus. 
_ Myown communications are founded upon observations made 
last year in Heligoland, and partly also during a subsequent 
residence on the coast of the Channel (chiefly at Ostend). ‘Their 
principal object is the discussion of three important points in 
the natural history of Awtolytus, in the face of the still greatly 
varying statements, as above indicated, namely :—in the first 
* Glanures zootomiques parmi les Annélides, p. 102, pl. 7. 
+ Die Borstenwiirmer, (Leipzig, 1864) p. 263. 
t Loe. cit. p. 109. 
§ Zeitschr. fiir wiss. Zool. Bd. xii. p. 115, pl. 11. figs. 1-6, and p. 464, 
pl. 42. figs. 5-11. 
13* 
