284 ' JOURNAL OF CONCHOLOGY, VOL. II, NO. 9, JANUARY, I906. 



this form as typical ("Guide to Mollusca," part i). The females 

 show more regularity,, only three out of fifteen specimens with irregular 

 laterals being female. Out of nine specimens with irregular laterals 

 five varied on the right side and four on the left. The above results 

 agree fairly well with Friele's numbers. I give one of his tables for 

 comparison : 



" In twenty-seven specimens from Hammerfest and Vardo, the 

 teeth were as follows {Jahrb. Deutsch. Mai. Ges., vol. 6, p. 257, 1879): 



It is thus seen that there may be as many as nine central teeth and 

 as few as three; in the one case in which I found three centrals, one 

 of the outside teeth was quite monstrous. There may be as many as 

 six laterals and as few as two. In many cases these are small knobs 

 showing a tendency to multiply lobes. In most cases the variation 

 continues throughout the radula. Troschel (" Gebiss der Schnecken") 

 expresses great surprise at a specimen having six central teeth 

 in front and five at the back, and, as is seen from the above table, 

 Friele found one from Hammerfest having six in front and eight at 

 the back. Two of my specimens were irregular in this way ; one had 

 seven centrals throughout and four laterals on one side, but the other 

 side had three teeth for thirty rows and then a very small fourth for 

 three rows, then three again and so on very irregularly. In the second 

 specimen the irregularity was in the centrals and in one side. On one 

 side were five laterals throughout, and on the other there were two 

 and a very small third for thirty-one rows and then only two. The 

 centrals were four and a small knob for five rows, then only four for 

 three rows and so on. 



The variations in Neptunea antiqua were much the same as those 

 found in Buccimun nndatum. Thirty-two specimens from 120-130 

 miles E. by N. of the river Tyne were examined. They were all 

 much alike, large, with thick shells, and deep yellow inside. Twenty- 

 eight were female, and four male ; the females appear to congregate 

 together. Fourteen radulas, thirteen of which were female, were 

 normal, that is to say, they liad three laterals on each side and three 

 centrals. The other eighteen varied as follows : — 



