4 DR J. STEPHENSON ON 
kegelférmige, kaum in der mitte eingeschniirte Sockel; beide schlank. Reservestilet- 
taschen mit je 3 Reservestiletten. L. etwa 13, Br. 0°75 mm.” ; 
Seeing that no particulars as to the stylet or its basis are given in the case of 
P. vermicularis, when allowance is made for slight variation of the shape of the head, 
length, etc., does any tangible difference remain ? 
Or, again—(i.) Cephalothria rufifrons (Johnst.): “ Weisslich. Mit 2 kleinen rot- 
blauen Pigmentflecken an der kopfspitze. L. 30-40, Br. 0°5 mm.” (ii.) Cephalothrix 
bipunctata (Biirg.): ‘“ Ockergelb, Kopf heller. Dicht vor dem Gehirn 2 kleine schwarze, 
seitliche Pigmentflecke. L. 60-100, Br. 1 mm.” 
I have considered a similar case at some length below; but again, in such cases as 
this, when necessary allowances are made, does anything remain ? 
It will, I think, be agreed that the present observations tend to show the inadequacy 
of many of the specific characters in use, and the need for new ones. It seems 
probable that such will have to be sought for in the details of internal anatomy, rather 
than, as has been the case with most of the old ones, among the external features. 
That this will make the description and identification of Nemertine species a more 
ditiicult matter than has hitherto been the case cannot be doubted. One has only to 
compare, for example, the laboriousness of the task of description of Enchytreeid or 
Tubificid species, where every identification requires a complete series of sections. 
(4) The fourth result which I believe has been reached is the union of two species 
of Cephalothrix into one, as just mentioned. I have considered this particular case in 
some detail, since I believe that it is typical of what will have to be done in the future 
in a number of similar cases. I have also, in another place, given reasons which seem 
to me to go far towards establishing the necessity for a similar treatment of two species 
of Prostoma. My observations also, as stated below, support the unification by JouBin 
and by BUrceEr of the two species Lineus gesserensis and L. sanguineus, considered by 
MacIntosh as distinct. It seems to me to be beyond doubt that further work on similar 
lines would have similar results in other species also. 
(5) Finally, I may mention here the observations on the physiology of the circu- 
lation in Cephalothrix linearis. In view of the paucity of such physiological observa- 
tions in this class they appear to be of interest. 
The nomenclature adopted throughout is that of the Tverreich. 
Tubulanus annulatus (Carinella annulata) (Montagu). 
Specimens are not common at Millport; they were found under stones near low- 
water mark at Balloch, and were dredged in 15 fathoms off Ascog Bank. 
Length 35-7 inches (85-170 mm.); breadth 1 mm., broadest at the anterior end, 
tapering gradually to a fine point posteriorly. These figures for the length of this animal 
are practically those given by Birarr in the Tverreich ; they are larger than those for 
specimens found at Naples (3) (8-10 cm.), though much less than those given by 
