MANSFIELD DISTRICT, VICTORIA. 
Fig. 2.—Ditto; impression of part of abdominal region, showing 
mould of pelvie fin-spines, incomplete behind 
(a, a), part of both pectoral fin-spines (4, 4), 
and some dermal tubercles (¢); nat. size. 
2a.—Cross-section of mould of pectoral fin-spine just 
beyond the hinder end of its inserted portion, with 
matrix occupying position of the groove on its 
narrow posterior face; nat. size. 
2b.—Similar cross-section near hinder end of pelvic 
fin-spine, showing its slight compression and an 
indication of the postero-internal groove; nat. size. 
2e.—Diagram of outer aspect of dermal tubercles with 
rounded bosses; five times nat. size. 
2d.—Diagram of tubereulated ridges of paired fin-spine; 
magnified (not satisfactory, the intervening grooves 
scarcely wide enough). 
2e.—Cross-section like 2a, but near the anterior end of 
the pectoral fin-spine; nat. size. 
Puate III. 
Fig. 1.—Gyracanthides murrayi, sp. nov.; portion of abdominal 
region showing remains of pectoral fin-spines with 
their slender distal end appearing vaguely through 
the hard matrix; numerous dermal tubercles (a); 
the pelvie fin-spines, evidently approximated by 
crushing, in part preserved, in part as impressions 
of the outer face (6); anda trace of the plate at 
the base of the posterior free pectoral spine (ce); 
nat. size. ; 
la.—Gutta-percha impression of the same specimen, 
showing the rounded shape and _ characteristic 
ornament of the bases of the pelvic fin-spines ; 
nat. size. 
1b.—Longitudinal broken section of the pectoral fin- 
spine of the same specimen, showing its fibrous 
structure ; nat. size. 
[27] Pe 
