279 



Girdle. — Is broad, covered with rather large, finely- 

 striated scales, placed at a more or less erect angle and barely- 

 imbricating; they are not pointed as in cariosus, Pilsbry; the 

 striae are not carried to the apex — this latter is smooth. As 

 compared with I. lincolnensis, Ashby, they are much larger 

 and more clumsy. The semi-erect character of the scales gives 

 them a chaffy appearance, and distinguishes this Ischnochiton 

 from any of our other true Ischnochitons. 



Hah. — I collected the type and one or two other speci- 

 mens near Port Lincoln, in South Australia, in January, 1917, 

 near the head of an almost land-locked bay, called Proper Bay. 

 I did not meet with it elsewhere. 



In Conclusion. — I submitted the type and foregoing 

 description to my friend, W. L. May, for his comments, and 

 select from the latter the following : — ''I think your shell is a 

 new species of Heterozona, as represented by suh-viridis, Ire. 

 and May, with a typical sub-viridis girdle but the sculpture of 

 I. atkinsoni, Ire. and May." Thinking that this comment 

 will be helpful I have quoted it, and also adopt his suggestion 

 to include the species under the sub-genus Heterozona, for the 

 erect character of the scales certainly suggests affinity there- 

 with, also the outer scales are small, increasing to large scales 

 near the shell ; but in the species under review, although some- 

 what irregular, the large scales do not appear in the midst of 

 the smaller ones, nor are they as pointed or prominent as 

 in typical members of this sub-genus, but are similarly finely 

 striated. I conclude, therefore, that it is a slightly modified 

 form of Heterozona. 



Note: — Just as I was leaving for America, in May, 1918, 

 I had hurriedly to close up the papers I was then writing on 

 Polyplacophora, and wishing at the time to recognize 

 the work done by Mr. F. L. Saunders by naming a 

 species after him, I selected a striking specimen from 

 my collection, giving a brief description only, under the 

 generic name of Anisoradsia. I had at that time no oppor- 

 tunity of making a careful examination with a good instru- 

 ment. On returning from America I felt dissatisfied with the 

 .generic identification and sent the type to Mr. Tom Iredale 

 for comparison with a similar specimen I had sent him in 1917, 

 and asking for his opinion. 



In the investigation of material for purposes of this paper 

 I liave found features connected with Heterozona cariosus, 

 C. and P., which lead me to conclude that the shell I named 

 Anisoradsia rnaidei saundersi, Ashby, was a divergent form of 

 that shell. Until the type is returned to me this must remain- 

 an open question. 



