LOXOSOMA LOXALINA AND LOXOSOMA SALTANS. 125 
each other by the occurrence of a rather wider interval 
between the first of the right and the first of the left and 
last of the right and last of the left. A papilla bearing stiff 
hairs lies between the two series at the oral end. The special 
modification in connection with the habit of jumping is in 
the four oral tentacles, that is to say the first and second of 
the two series, forming the four on the inflected edge of the 
lophophore. These are longer than the rest, and when 
closed down over the mouth fold outside and across the 
tentacles of the lateral parts of the lo[)hophore as in fig. 19. 
These four usually work together and are raised off the floor 
of the calyx quite independently of the othei-s. When the 
animal moves its position these four tentacles play a part in 
the action. 
The stalk of the animal is extremely stroTig and muscular, 
iind can swing the body about' in any direction with ease and 
i-apidity. The calyx may be directed outwai'ds from its point 
of attachment, so that where expanded it shows a campanu- 
late form as in fig-. 10, which resembles the ordiiiary 
Pedicellina condition rather than that typical of the genus 
Loxosoma, and in this respect it is more like Urnatella. 
When lying prone, as presumably it must often do while 
between the worm and tube, we may suppose that it lies with 
its oral surface towards the object to which it is attached, as 
this is the position it more usually takes when not waving 
outwards. Prouho’s figiu*es seem to show that L. annelidi- 
cola lies the other way. It is in this position that locomo- 
tion is possible. 'I'liis is effected by the animal bending down 
its body and lophophore into contact with the surface over 
which it is about to move, but contact is made only by the 
tips of the four large oral tentacles, which are provided with 
special stiff bristles on their outer tips (fig. 10), which do not 
occur in the other tentacles. These no doubt serve to give 
it a hold. The four tentacles are then suddenly bent back- 
wards, that it to say outwards, and at the same moment the 
|)eduncle is whisked forwai'ds with great i-apidity, and the 
adhesive foot applied in a fresh situation, as in Text-fig. 1. 
