NOTACANTHUS SPINOSUS. 301 
NOTACANTHID. 
Notacanthus spinosus sp. n. 
Plate L’, fig. 4, 4a, 4b. 
Br. r. 12; D.9 +1; A. ca. 17 + 106-112; V. 3-446; P. 14; C.6. 
Form elongate, compressed, thin and slender posteriorly, depth near one 
tenth of the total length; tail band-like, tapering. Head about one sixth of 
the entire length, compressed, pointed. Snout medium, acute, one and one 
fourth times as long as the eye, preoral portion three fourths of the length 
of the orbit. Eye large, two elevenths of the length of the head, four fifths 
as long as the snout, equal the width of the interorbital space. Mouth of 
medium size, below the snout, directed forward and downward; maxillary 
bifid and bearing a suborbital spine. Teeth small in a single series on jaws 
and palatines, declinable, compressed and thin edged, acute, about fifty on 
the upper and fifty-two on the lower jaws. Nostrils close together, in front 
of the eye and nearer to it than to the end of the snout, similar to those of 
Halosaurus, posterior larger, anterior with a hood-like valve open forward. 
Operculum broad, thin, flexible, supported by twenty-one or twenty-two rays 
similar to the branchiostegal. On the suboperculum there are five or six 
additional rays. Twelve to thirteen branchiostegal rays. Gill openings 
wide; membranes united below, but free from the very narrow isthmus. 
Gill rakers short, 3 + 9 on the front of the first arch. Gills four, six rakers 
in the slit behind the fourth; laminz well developed. A broad glandular 
mass above the gills inside the upper angle of the opercle below the forward 
end of the lateral line; apparently adventitious since it rests upon the lin- 
ing membrane of the gill chamber from which it is not hard to scrape away. 
Dorsal origin nearly one length of the head backward from the opercu- 
lum; rays nine or eight erectile spines and a single soft ray behind the 
hindmost spine. Ventrals small, little more than one third as long as the 
head; bases ending below or forward of the first spine of the dorsal; fins 
united by membrane. Most often there are three simple spines and six soft 
rays to each ventral; in one case there are seven soft rays, and in two 
others there are four spines, the fourth being furnished with an additional 
cusp in front. Anal origin below the third dorsal spine; fin with about 
seventeen spines in most cases, one specimen has twelve, another nineteen. 
Pectorals small, fourteen-rayed, reaching a vertical from the origin of the 
