Fig. 388.—Phyllopteryx eques. ½ nat. size.
An Australian species of Syngnathus has been described by E. P. Ramsay under the name of S. intestinalis, from its living inside Holothurians, in the manner of Fierasfer, and G. Lunel has observed a Doryichthys to offer a similar instance of inquilinism.
One of the most remarkable types of Syngnathids is Phyllopteryx, from Australia. The spines and knobs of the head and body are furnished with dermal appendages, which closely imitate the fucus among which they live.
Fam. 11. Pegasidae.—Body short or moderately elongate, encased in an exoskeleton forming rings. Anterior vertebrae not elongate; no ribs. Snout produced beyond the mouth, which is small, inferior, and toothless; no praeoperculum, no symplectic; gill-opening very small; gills pectinated. A single dorsal fin. Pectoral fins large, horizontal; ventrals reduced to one or two filamentous rays, behind the scapular arch. Air-bladder absent.
Five or six species, referable to two genera, Pegasus and Parapegasus, make up this family. They are very small fishes, inhabiting the coasts of China, Japan, Arabia, the Malay Archipelago, and Australia. Pegasus is remarkable among all fishes in having the five anterior rays of the pectoral fin transformed into strong spines.
Sub-Order 8. Percesoces.
Air-bladder, if present, without open duct. Parietal bones separated by the supraoccipitaL Pectoral arch suspended from the skull; no mesocoracoid arch. Ventral fins, if present, abdominal, or at least with the pelvic bones not solidly attached to the clavicular arch.
This group connects the Haplomi with the Acanthopterygii, the Scombresocidae being somewhat related to the Cyprinodonts,[[706]] whilst the Anabantidae show distinct affinity to the Osphromenidae in the following sub-order. Other families, previously included among the Scombriform Acanthopterygians, are placed here on the assumption that the loose attachment of the pelvic bones to the clavicles is a primitive character, and not the result of degeneration, such as occurs in some cases among true Acanthopterygians. Although this sub-order is perhaps only an artificial association, it must be borne in mind that, notwithstanding the very wide divergence which exists between the first and last families, and however dissimilar their members may appear to be at first sight, a gradual passage may be traced connecting the most aberrant types.
Synopsis of the Families.
I. Ventral fins, if present, inserted far behind the pectorals; no spines to the fins.