FISHES--PHENOMENAL AND ECONOMICAL. 187 
In Gastrotokeus biaculeatus, an elongate, grass-green species, a yet nearer 
approach is made to the ordinary Pipe-fishes. The tail, however, possesses the same 
prehensile character as that of the Sea-horses. Gastrotokeus is an essentially tropical 
type, occurring on the North Queensland coast and on the north-west coast of 
Western Australia. In common with Phyllopteryx and Solengognathus, the male 
individual of Gastrotokeus fulfils the ré/e of foster parent to the infant brood, 
receiving and taking care of the ova, which throughout the period of incubation are 
firmly embedded by their bases in the soft abdominal membranes, until they are 
hatched. The ova of both Phyllopteryx and Gastrotokeus are of large size, of a 
delicate pale pink hue in the latter and a bright clear red in the first-named type. 
In many of the ordinary Pipe-fishes the eggs, carried by the male, are enclosed in 
membranous folds of the skin, while in the Sea-horses, Hippocampus, there is a true 
pouch or marsupium for their reception. As may be anticipated by the small aperture 
of the mouth in all of the members of this group here enumerated, their food is of 
the most minute description, consisting almost exclusively of Entomostracous crustacea 
and the larval forms of the larger species. 
Some of the most outré-shaped and brilliantly coloured members of the 
Australian fish fauna are included in the very distinct group of the Plectognathi. 
This series is represented most conspicuously by what are known popularly in 
Australia as Leather Jackets and Cow-fishes, belonging respectively to the genera 
Monacanthus and Ostracion. Although the Plectognathi are usually represented 
as fish which are essentially characteristic of tropical or sub-tropical seas, the 
greater number and more brilliant of the Australian species pertain to the tempe- 
rate waters of that Island-Continent, and are notably abundant on the extreme 
southern sea-board of Tasmania. As with the Syngnathidee, a coloured plate, Chromo- 
Plate VII., has been set specially apart for the illustration of characteristic members 
of this group. 
Of the Australian Cow-fishes, so-called with reference to the _ horn-like 
prominences which are usually developed from the frontal region of their indurated 
carapace-like integument, the Tasmanian species Ostracion or Aracana ornata is a 
brilliant example. The males and females of this species are so differently coloured 
that they were originally, as in the case of the British Cuckoo Wrass, Labrus miztus, 
supposed to represent two distinct species, and had conferred upon them the separate 
titles of Ostracion ornata and O. aurita. The specific identity of the two species has 
been amply demonstrated in examples examined by the writer, one particularly interesting 
