974 MR. F. A. POTTS ON 
déchirures. I] m’a semblé quelles s’anastomosaient parfois, ce- 
pendant j’éprouve quelque hésitation & affiumer ce point. Ilya 
done, on le voit, encore bien des questions 4 vider au sujet de ces 
vers.” 
The incompleteness of Claparéde’s observations leaves us in 
some uncertainty with regard to P. socialis. As I understand 
the foregoing passage, he was unable to assure himself as to which 
.of the following alternatives was correct. Either ; 
(1) There are a number of unbranched tubes packed close 
together, but without connection, each tube containing two or 
three individuals, but having only a single opening ; 
Or else (2) these adjacent tubes are in reality connected with 
one another, and the whole bundle of tuhes (ceppa) is a single 
colony, all the worms contained in which have probably been 
budded off from a single original individual. This is supported 
by the fact that sne worms in a bundle are all of the same sex. 
In P. prolifica, on the other hand, the relations of the tubes 
are perfectly clear. Where they come into contact they do not 
adhere in the complex manner described by Claparéde. In the 
following paragraph I state shortly the conditions which are 
found in the colonies. 
The tubes are comparatively long and sometimes divide into 
two or more branches of approximately equal length. Most 
contain more than one worm and some as many as six. The 
main tube is provided with several short branches which open to 
the exterior, but the number of openings does not correspond to 
the number of worms in the tube. The worms can change their 
position in the tube fairly rapidly and can turn round and pass 
each other. Those individuals which occupy a favourable position 
protrude their long tentacles from one of the openings to assist 
in the collection of food. 
It occurred to me on first observing the above facts, while I 
was still unaware of Claparéde’s observations on L. socialis, that 
an explanation was probably to be found by supposing some sort 
of asexual reproduction to occur in the species. The nature of 
this reproduction was indicated by a discovery made during an 
early examination of the living material at Departure Bay. 
T was surprised to find emerging from freshly dredged tubes 
very short individuals which differed considerably from the 
normal forms in the constitution of their bodies. One of these 
only measured 6 mm., which is +—7 of the normal length. The 
3 = 
segments of which it was composed were arranged as follows :— 
Anterior region ...... 8 segments. 
Median LS Vy Fa Bk 2 es 
Posterior 2 hee 20-30 ,, 
Not only did the anterior region consist of less than the 
normal number of segments (12), but also there was no segment 
with a modified seta such as occurs in all adults of the species, 
and the peristomial tentacles were represented by minute stumps. 
The number of segments in the median region was exceedingly 
