Gcniifi Li It thill, in Victoria. 399 



IV. — Linthia nelsoni, McCoy, sp. 



1882. Pericosmns nelsoni, McCoy. Prod. Pal. Vic, Dec. 

 vii., pp. 17-19, pi. 66, f. 1, 2, and pi. 67. f. 1. 

 1891. Pericosmus nelsoni, Tate. Trans. Roy. Soe. S.A., 

 vol. xiv., pt. 2, p. 277. 



Observations. — This species which, so far as I am aware, has 

 only been collected from the Waurn Ponds quarries, which are 

 situated about seven miles west of Geelong, appears on examina- 

 tion to require its removal from the genus Perirnsmns to 

 Linthia. All the characters of my specimens agree absolutely 

 with those of Linthia, and also with McCoy's description of the 

 above species, with the exception of the courses of the fascioles. 

 In my examples there is a distinct and complete peripetalous 

 fasciole, and a latero-sub-anal fasciole, which starts from the 

 peripetalous a little above and behind the end of the anterior 

 lateral petal. McCoy figures a basal view (plate 66, f. 2), which 

 is very misleading in its anterior and posterior aspect. Through 

 the courtesy of Mr. F. Chapman I have been able to examine 

 McCoy's type and figured specimens, in addition to other ex- 

 amples, preserved in the National Museum, Melbourne. I was 

 very much surprised to find McCoy's original material in such an 

 imperfect state, and so poorly preserved, and this no dou])t 

 accounts for the discrepancies which appear to exist. On plate 

 66, figure 1, the posterior dorsal keel is abnormally flattened 

 owing to crushing, whilst it is really distinctly angularly keeled 

 in perfect specimens. 



Plate 66, figure 2, shows the base of another crushed specimen, 

 but I was unable to detect the anterior portion of the peri- 

 petalous fasciole in the position as figured ; it is just discernible 

 on the front margin, but could not be visible in the view as 

 shown, unless the artist's licence goes so far as to permit, first, a 

 tipping up of the posterior end to include a view of the periproct, 

 and then a similar treatment for the front of the test, to include 

 as much character as possible. 



Figure 1, on plate 67, is wrong in its fasciole track, for while 

 one side of this specimen is somewhat obscure, the other dis- 

 tinctly shows the lateral fasciole running up to and joining 



