64 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
French Ampharetinse.* — M. P. Fauvel has a note on this family, 
which is very poorly represented on the coasts of France. Some 
additions are made to our knowledge of Amjpharete grubei , which has 
been found in comparative abundance in the neighbourhood of the 
French Zoological Station at Tatihou. 
Septal Organs of Owenia fusiformis.f — Prof. G. Gilson calls 
attention to certain peculiarities presented by the septa of this worm. 
All of them, with the exception of the first and the most remote, are 
perforated, and each has two pores through which the adjoining segments 
communicate. These pores are provided with a muscular apparatus 
which in certain of the septa is very powerful. In the second septum, 
which is the most muscular of all, there is an enormous ovoid mass of 
muscles through which passes a tiny canal. This septal canal is very 
sinuous in its course and its existence is not easy to recognise, owing to 
the state of violent contraction in which the muscles are always found 
in sections. There is no doubt, however, that they may open widely 
enough to allow the eggs to pass and reach the fifth segment of the 
body, which is the only one that communicates with the exterior. In 
the fifth and sixth septa the muscular mass on each side is joined by a 
tubular ingrowth of the epiderm. This tube protrudes into the septal 
tissue until it meets a cavity which communicates with the septal canal 
and with the anterior segments. With regard to the function of these 
pores, the author points out that the worm swells or dilates its body, 
when it wants to adhere to the sheath in which it lives. The resistance 
indeed is so powerful that it is quite impossible to pull the worm out 
of its tube without breaking the body in pieces. When a part of the 
body has been cut off the remaining segments do not relax at all, but 
remain as turgid and resisting as before. This shows that the various 
segments of the body may swell or relax quite separately. It may be 
concluded therefore that the curious septal organs of Omnia are valves 
intended to regulate the pressure in the separate chambers of the 
perivisceral cavity, and to eventually divide entirely from one another 
those which at a given moment the animal desires to dilate. 
Blood-forming Organs in Larva of Magelona.J — Miss F. Buchanan 
points out that there is a good deal of individual variation with regard 
to the time of the first appearance of the vascular system, as there is 
indeed with regard to that of other organs also, in the larva of Magelona. 
The “ heart ” is always the first part of the vascular system to make its 
appearance, and the dorsal and ventral vessels after it are formed, to 
begin with, by the accumulation of a transparent fluid between the 
splanchnic layer of mesoblast and the hypoblast. This causes a 
pouching of the splanchnic mesoblast in front to form the walls of the 
“ heart.” By the time that the larva has reached the stage in which 
the body is divided into three regions there is seen at the posterior end 
of the dorsal vessel, and in the middle region of the body, a dark 
reddish-brown mass. This mass is seen in section to consist of a much 
swollen portion of .the mesoblast in which there are many nuclei, but no 
distinct cell boundaries. In later stages, when the splanchnic layer 
* Mem. Soc. Sci. Nat. Cherbourg, xxix. (1895) pp. 328-48. 
t Bep. Brit. Ass., 1895, pp. 728 and 9. $ Tom. cit., pp. 469 and JO. 
