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26. ISCHNOCHITON VERCONIS, sp. nov. FL 
Plate xxiv., figs. 1a,b,c,d,e,f. 
Mr. Hedley says: “This is certainly a new species and a 
magnificent one. One would need to disarticulate a valve 
to be sure of the classification. Probably it is an Zschnochi- 
tou, and perhaps of the section /schnoradsia.” As only one 
specimen was found I am not disarticulating, but hope to. 
supplement my description later. 
General Appearance. Shell elliptical, flattened, side 
slopes curved. Colour, uniformly slatish-grey, tending to 
heliotrope. Girdle and valves of the same colour. 
Anterior Valve. No very distinct markings. Surface 
rough with irregular concentric growth lines and minute 
longitudinal striz. Hight teeth. 
Posterior Valve. Mucro-median, prominent; divided 
into two distinct areas by a slightly-raised riblet running up 
to the mucro. The anterior half has longitudinal colour 
markings with microscopic nodulose lines. To the unaided 
eye it seems smooth. The posterior half has concentric 
irregular nodulose lines similar to the anterior valve. 
Median Valve. The pleural and dorsal areas run 
together, while the lateral area is very distinct. The dorsal 
area is smooth, horny, with brown-pencilled longitudinal 
lines and microscopic zigzag striations. The pleural area has 
very delicate longitudinal markings. The lateral area is dis- 
tinctly raised and has a lighter shade of colour than the 
pleural. The very slight longitudinal and lateral markings. 
give it a textile appearance. 
Gudle. Clothed with imbricating scales, curved, apices 
suberect; under the microscope the scales are beautifully 
frosted over and show about ten transverse parallel grooves. 
The girdle is one-third of the depth of the lateral area, 
about 3 mm. across. 
Interior. Bluish-grey colour with broad sinus and dark 
splashes near the sinus of each valve. The anterior valve 
has delicate brown pencillings from the sinus to half its 
depth with eight riblets. 
Measurement. Dried specimen. Length, 44 - mm. ; 
breadth, 28 mm. 
Habitat. Rockpool, inside reef, Ellenbrook, south of 
Cape Naturaliste, Western Australia. 
Remarks. It is different in shape from any Australian 
Ischnochitons, and the only specimens in my collection of 
similar shape are JJopolia lynosa, Gould, from California, 
and Chiton Magnificus, Deshayes, from the Philippines. This 
species has been named after Dr. Verco, to whose generosity 

