16 DR J. STEPHENSON ON 
The shape of the basis in my specimens is seen in fig. 7. It will be seen that 
the constriction is very slight, if indeed it exists—if, that is, the appearance of a 
slight constriction be not merely due to the rather greater width of the posterior 
rounded end of the basis; the posterior part of the basis is, owing to this greater 
width, bulkier than the anterior. Fig. 8 represents a different shape, met with on 
one occasion only ; the basis is here much shorter and broader than usual, and resembles 
a truncated cone. In the two reserve sacs I have found either two or three stylets. 
The number of proboscis nerves is not given in any account of the species that 
I have seen. Since it varies in the different species of this genus, and since it is a 
character that is sometimes used as a specific distinction, it may be worth while stating 
that the number is fourteen. 
The cwcum sends off a pair of long and slender prolongations, which reach as far 
as the brain. These, which are usually described as hollow pouches, are in my prepara- 
tions solid throughout. As stated by other authors, the cerebral organs are large, and 
situated in front of the brain. 
This form appears to be a good example of the variability of the class. JouBIN’s 
account of the cephalic grooves differs considerably from those of MacInrosH and 
myself; Bireer’s specimens differed from the British forms in being found at some 
depth, in possessing a much larger number of eyes, in the shape of the basis of the 
stylet, and in coiling themselves up, not contracting themselves slug-like; the colour 
also, as in most members of the class, is variable; and even in the Millport forms I 
found in one instance, as has been noted, a considerable divergence from the rest 
in the shape of the basis of the stylet. 
Amphiporus pulcher (Johnst.). 
This species has been the subject of a number of descriptions which vary from each 
other considerably in certain points, e.g. the eyes, the cephalic grooves, and the stylet. 
A comparison of the forms met with at Muillport with those described from other 
localities may therefore be of interest. 
Specimens are rare at Millport; three were dredged in fifteen fathoms off Ascog 
Bank. This supports JouBIN’s statement (8) that ‘on ne trouve pas non plus les deux 
especes (7.e. A. pulcher and A. lactifloreus) dans les mémes localités.” 
The length was about 1} inch, the body relatively broad and flat; the tail much 
flattened ; the head not wider than the rest of the body, somewhat rhomboidal in shape, 
ending anteriorly in a blunt point. The animals are sluggish in habit, contracting 
readily to a slug-like mass 4 of an inch long; they can swim lazily, ventral side upper- 
most, at the surface of the water. Ihave not seen the peculiarity noted by MacIntosu, 
that, when irritated, they turn on edge and swim rapidly through the water by swift 
lateral strokes of the oar-like extremity. 
The colour is a light orange-pink, the margins and ventral surface being lighter, of a 
