nisi TSSION iM' Ml. ll~ AND THEIE DISTRIBUTION. l~i 5 



PERISTEDION TRUNCATUM, Gl vim r. 



Ptriatelhus truncatum, GUnther, Challenger Report i, Pari 6, 1880, 7. pi. n, fig. A. 



Tlie length of the preorbital processes is contained twice ami three fourths in the dis 

 tance between their extremities and the anterior margin of the orbit, [uterorbital space 

 deeplj concave, with a depressed smooth groove along the middle; a minute spine od the 

 base hi' each preorbital process, but no other mi the upper surface of tin' snout : lower jaw 

 with enormous barbels, the longest being fringed. The preopercular ridge does uol extend 

 beyond the hind margin of tin 1 bone, and is not produced into a spine; also the opercular 

 ridge terminates in a short ami truncated projection. Bach scute of the bodj with a 



I ked spine. Each of the bonj plates between the ventral fins is nut quite twice as long 



as broad. Rose-colored, with small, irregular brownish spots on tin- upper parts. 



Radial tin inula: I), vii, 19; A. 20; L. lat. 32. 



The type of this species, a specimen i>A inches long, was taken bj the Challenger at 

 station L22, off the coast of Pernambuco, in 30 or 350 tat I nuns or in some intermediate depth. 



Dr. Giinther, though, unwilling to commit himself as to tin 1 bathybial habitat of anj of 

 tin' forms collected by tin- Challenger at station 122, preferring to include them all in his 

 report upon t he shore-fishes, has nevertheless described one of the fishes there taken, under 

 the very significant name of Bathyanthias. 



Suborder T^ENIOSOMI. 



Toeniosomi, Gill, American Naturalist, \\i, 1887, 86; xjs.iv, 1890, 481. 



Teleocephals with the scapular arch subnormal, post-temporal undivided ami closely 



applied to the back of the cranium, between the epiotic ami pterotic, or upon the parietal ; 

 hypercoracoid perforate at or near the margin; cranium with the epiotics enlarged, en- 

 croaching backward and juxtaposed behind, intervening between the exoccipitals and 

 supraoccipatal; prootic and the opisthotic represented chiefly by the enlarged prootic; 

 suborbital chain imperfect; the scapular bones separated by intervening cartilaginous ele- 

 ments; the hypopharyngeals styliforra and parallel with the branchial arches; epipharyn- 

 geal in full number (4 pairs), and mostly compressed: the dorsal tin composed of inarticu 

 late rays or spims. separable into lateral halves, and the ventral s (when present) sub- 

 brachial. 



A myodome may be present or absent, none being developed in the Regalecidae, but 

 one being distinct and supplemented by a die host in the Trachypteriibe. | Gill.) 



••The ribbon fishes." says Giinther, " are true deep sea fishes, met with in all parts of 

 the oceans, generally found when floating dead on the surface, or thrown ashore by the 

 waves. Their bodj is like a band, specimens of from 15 to 20 feet long being from L0 to 

 12 inches deep and about an inch or fwo broad at their thickest part. The esc is large 

 and lateral; the mouth small, armed with very feeble teeth; the head deep and short. A 

 high dorsal tin runs along the whole length of the back, and is supported In extremely 

 numerous rays; its foremost portion, on the head, is detached from the rest of the tin, ami 

 composed of \ erj elongate flexible spines. The anal tin is absent. The caudal fin (if pre 

 Served, which is rarely the case, in adult specimens) has an extra axial position, being 

 directed upwards like a fan. The ventrals are thoracic, either composed of several rays or 

 reduced to a Bingle long filament. The coloration is generally silvery, w ith rosy tins. 



■•When these lishes reach the surface of the water the expansion of the gases within 

 their bodies has so loosened all the parts of their muscular and bon\ system that they can 

 be lilted out of the water with dillicully only, and nearly always portions of the body and 

 tins are broken ami lost. The bones contain very little bony matter, are verj porous, thin, 

 and buhl. At what depth ribbon lishes live is not known: probably the depths vary for 

 different species; but although none have been yet obtained by means of the deep-sea 

 dredge, thej must be abundant at the bottom of all oceans, as dead lishes or fragments of 

 them an- frequently obtained. Some writers have supposed from the greal length and 

 narrow shape of these lishes that they have been mistaken for 'sea serpents,' but as these 



