POL Y CHiETA—BEN HAM. 
29 
Remarks .—From these southern seas, four species of Autolytus have been recorded—- 
A . maclearanus McIntosh, A. gibber Elders, A. simplex Fillers; in addition to 
Gravier’s species. But the last is the only one in which the “ ailerons ” 
are developed, as Elders has pointed out (1913). 
Epitokous phases. 
A considerable number, some 3-4 dozen, of male and female epitokous stages were 
collected on the surface at Boat Harbour. They are described by Dr. McLean as being 
“ reddish in colour.” In the preserved state some are deep brown, others pale brown, 
and others again almost white ; they all agree in their structure though it may be that 
the darker ones are older than the rest*. 
The brown ones are of deeper tint on the ventral than on the dorsal surface, 
which suggests that the worms swim on their backs at this time. Naturally they vary 
in length, the majority being from 12-18 mm. In each case I have chosen for description 
one of the largest specimens. 
« Sacconereis. 
The majority of the females have lost the ventral egg-sac, though this is still 
present in one that was mounted, where it lies behind the 15th chsetigerous segment. 
A complete large individual, measuring 38 mm. in length with a breadth of 5 mm., 
consists of a “ head ” with 14 unmodified segments, plus 40 segments with longer 
parapods, each carrying a bundle of long capilliform notopodial bristles ; this region is 
followed by 30 unmodified posterior segments. 
The head in this phase undergoes little modification ; there are no additional 
prostomial appendages ; but the eyes are enlarged, specially those of the anterior pair 
which have become thrust down to the under surface. 
The ailerons are distinct. 
The dorsal surface of the body is marked by intersegmental bands of yellowish 
brown pigment which encroach more or less on to the surface of the segments. The 
dorsal cirri retain the colouration of the atokous phase, brown with a white line along 
each face. 
PolybostricJius. 
In the male, the prostomium is white, but the appendages are more or less deeply 
tinted. The tentacles are brown on the anterior or ventral faces, and white dorsally ; 
the frontal tentacles, like the “ bifurcated appendages,” are deep brown ; the dorsal 
cirri are paler dorsally than ventrally. 
A complete individual, measuring 32 mm. in length, consists of a “ head ” with 
14 unmodified chtetigerous segments, followed by 45 segments with long capilliform 
bristles, behind which are again some 20 unmodified segments. 
* When placed in water previous to being stained in alum-carmine the pigment is dissolved, and the water becomes 
coloured an orange-brown, 
