190 THE NATURALIST IN AUSTRALIA. 
respectively from a few inches to about a foot and a half in length. Several of them 
inhabit the colder waters of the Southern Tasmanian coast-line, and one of these, 
Monacanthus rudis, has been selected as the central illustration in Chromo-Plate VII. 
It is worthy of remark that the individual here portrayed is a male fish, bedight in 
what might be denominated his wedding livery, his resplendent garb of blue and 
yellow being at other seasons of the year replaced by sober tints of brown and white. 
This fact was ascertained through the writer keeping this specimen for a considerable 
interval at the Hobart fishery establishment. A familiar instance of a British fish 
undergoing an almost equally remarkable colour metamorphosis is afforded by the 
male of the common Stickleback, Gasterosteus aculeatus, who, during the mating 
season, exchanges his everyday dress of silvery grey for a most gorgeous corselet of 
gold and scarlet and shining green. 
In many of the common species of Australian Leather Jackets, notably 
Monacanthus hippocrepis and M. Ayraudi, lines, spots or suffused patches of rich cobalt 
blue are permanently conspicuous, rendering them among the gayest members of the 
Australian fish fauna. Added to this, many of the species are distinguished by an 
abnormal development of their fins or by body excrescences, which impart to them a 
most bizarre aspect. Thus, in one species, M. megalurus, a pouch-like membrane 
is developed on the chest ; in many instances, horny, hook-like structures protrude in 
the male individuals on each side of the tail; while in one form, M. Browni, also 
taken in Tasmania, these horny hooks are replaced by a lozenge-shaped, tooth-brush- 
like patch of bristles. 
Notwithstanding their somewhat abnormal appearance, and the fact that they 
represent an order which includes the highly poisonous Toad-fishes, Leather J ackets, 
though but rarely brought to the fish market, have been pronounced by 
connoisseurs to be most excellent eating, and, if skinned before cooking, as 
being equal to the much-esteemed Sole or Flounder. In such high estimation, in 
point of fact, were these fish regarded by one of the earlier Tasmanian settlers, 
an ancestor to a reigning judicial functionary, that these fish are still known to 
the local fisher-folk by the patronymic of their whilom appreciator. Leather 
Jackets are by no means regarded with favour by the ordinary line fishermen. 
The smaller species have a special knack of nibbling the bait off the hook 
with their trenchant chisel-like teeth, while the larger ones can with the same 
weapons easily sever a stout line or a steel hook of moderate thickness. When 
caught, they on the same account demand wary handling, a nip from the 
