New cuttlefishes from the North West Shelf 
307 
Figure 24 A-B, Sepia sulcata Hoyle; A, cuttlebone, dorsal view, female WAM 339-86, 60.9 mm ML, arrow indicates 
median longitudinal ridge; B, ventral view, same specimen. Scale bars 6 mm. 
type specimen. The discovery of new material 
among collections of the Western Australian 
Museum and Museum of Victoria has enabled a 
redescription based on the type and this new 
material, thus adding information on females 
(which previously were unknown) and has 
provided more information on the distribution of 
the species. In most respects, the Australian 
material conforms to Hoyle's (1885) original 
description which was based on the single male 
type specimen. Some differences, however, were 
found. The two dorsal arms are described as 
bearing biserial suckers. We have found that while 
suckers are biserial for most of the length of these 
arms, they are arranged in 4 series on the extreme 
distal tips of both arms in males. The dub suckers 
in the type specimen are arranged in 7 rows, while 
those of the Australian specimens are usually in 5 
rows, rarely 6, or 7. Hoyle (1885) reports the 
presence of a few minute papillae on the posterio- 
dorsal surface of the mantle. Aside from the short 
bars described above (which may be the same as 
those that Hoyle (1885) is referring to), no other 
papillae could be found on the dorsal side of the 
mantle in the specimens examined in this study. 
The modification of the hectocotylised arm in the 
type specimen is typical of immature males of this 
species. While the suckers are reduced on the left 
ventral arms in all males, the degree of 
development of the median furrow differs 
depending upon the state of maturity of the 
animal. In males determined to be immature due 
to the absence of spermatophores in the 
spermatophore storage sac, the median furrow on 
the hectocotylus may be absent (as in the type 
specimen (Figure 20A)), or only weakly developed 
as a small pit, or depression at the base of the arm. 
In mature males, the furrow is deep and 
pronounced (Figure 20B). Hoyle (1885) describes 
the suckers on the distal portion of the 
