Although an alleged sand-lance, Rhynchias septipinnis, with ventral fins abdominal, was described a century ago by Pallas, no one has since seen it, and it may not exist, or, if it exists, it may belong among the Percesoces. The relation of Ammodytes to Embolichthys is too close to doubt their close relationship. According to Dr. Gill the Ammodytidæ belong near the Hemerocœtidæ.
Fig. 476.—Pearlfish, Fierasfer dubius Putnam, embedded in a layer of mother-of-pearl. La Paz, Lower California. (Photograph by Capt. M. Castro.)
The Pearlfishes: Fierasferidæ.—In the little group of pearlfishes, called Fierasferidæ or Carapidæ, the body is eel-shaped with a rather large head, and the vent is at the throat. Numerous species of Fierasfer (Carapus) are found in the warm seas. These little fishes enter the cavities of sea-cucumbers (Holothurians) and other animals which offer shelter, being frequently taken from the pearl-oyster. In the Museum of Comparative Zoology, according to Professor Putnam, is "one valve of a pearl-oyster in which a specimen of Fierasfer dubius is beautifully inclosed in a pearly covering deposited on it by the oyster." A photograph of a similar specimen is given above. The species found in Holothurians are transparent in texture, with a bright pearly luster. Species living among lava rocks, as Jordanicus umbratilis of the south seas, are mottled black. Since this was written a specimen of this black species has been obtained from a Holothurian in Hilo, Hawaii, by Mr. H. W. Henshaw.
Fig. 477.—Pearlfish, Fierasfer acus (Linnæus), issuing from a Holothurian. Coast of Italy. (After Emery.)
The Brotulidæ.—The Brotulidæ constitute a large family of fishes, resembling codfishes, but differing in the character of the hypercoracoid, as well as in the form of the tail. The resemblance between the two groups is largely superficial. We may look upon the Brotulidæ as degraded blennies, but the Gadidæ have an earlier and different origin which has not yet been clearly made out. Most of the Brotulidæ live in deep water and are without common name or economic relations. Two species have been landlocked in cave streams in Cuba, where they have, like other cavefishes, lost their sight, a phenomenon which richly deserves careful study, and which has been recently investigated by Dr. C. H. Eigenmann. These blind Brotulids, called Pez Ciego in Cuba, are found in different caves in the county of San Antonio, where they reach a length of about five inches. As in other blindfishes, the body is translucent and colorless. These species are known as Lucifuga subterranea and Stygicola dentata. They are descended from allies of the genera called Brotula and Dinematichthys. Brotula barbata is a cusk-like fish, occasionally found in the markets of Havana. Similar species, Brotula multibarbata and Sirembo inermis, are common in Japan, and Brosmophycis marginatus, beautifully red in color, is occasionally seen on the coast of California. Many other genera and species abound in the depths of the sea and in crevices of coral reefs, showing much variety in form and structure.
Fig. 478.—Brotula barbata Schneider. Cuba.
