NOTACANTIIUS SPINOSUS. 301 



NOTACANTHID/E. 

 Notacanthus spinosus sp. n. 



Plate L', fiij. 4., 4<«, 4^- 



Br. r. 12 ; D. 9 + 1 ; A. ca. 17 + 106-112 ; V. 3-4 + 6 ; 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 eve and nearer to it than to the end of the snout, similar to those of 

 Halosaurus, posterior larger, anterior with a hood-li^e 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 ; laminte well developed. Abroad 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 

 imited 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-raved, reachins; a vertical from the origin of the 



