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644 TELEOSTEI CHAP. 
12 feet, it must be immune to their influence: a remarkable 
condition, considering that small fish have often been seen in 
their stomachs and entangled in their tentacles.” This observer 
adds: “It is probable that, in addition to protection, the fish 
derives its food from association with the Physalia, much as does 
the Remora in accompanying a shark. The Physalia doubtless 
paralyses many more animals than it can consume—the residue 
falling to the lot of the fishes, which may be present to the 
number of ten.” 
Fam. 10. Icosteidae.—The so-called “ Rag-Fishes,” in which the 
skeleton is quite soft and cartilaginous, are aberrant deep-sea 
forms evidently related to the Stromateidae; they lack the 
oesophageal teeth and the processes of the last gill-arch, but 
Icosteus at least has the gill-raker-like knobs below the pseudo- 
branchiae. The pelvis is widely separated from the clavicles. 
Spines are absent in the fins, and the body is naked or covered 
with small cycloid scales. Vertebrae in large number (up to 70). 
Icosteus, Icichthys, and Acrotus, each with a single species, 
from the Pacific coast of North America. 
Fic. 393.—Icosteus enigmaticus, x4. (After Goode and Bean.) 
Fam. 11. Ophiocephalidae.—Maxillary excluded from the 
border of the upper jaw. Head and body covered with cycloid 
scales. Anterior ribs sessile, the remainder inserted on the para- 
pophyses. Pectoral fin low down; ventral fin, if present, near 
the pectoral, with 6 soft rays; pelvic bones connected with the 
clavicular symphysis by ligament. Dorsal and anal fins long, 
without spines. <Air-bladder present, much elongate. 
These Fishes are provided with an accessory superbranchial 
cavity, and are able to breathe atmospheric air. All are inhabi- 
