No.1635. FISHES FROM JAPAN AND h'll Ml ISLANDS -SNYDER. 1Q5 



bar on opposite side; sides of head with round light spots; (ins 

 checkered with brown spots. In young examples (he general color is 

 brownish gray, the bars standing out boldly, except the second on 

 body, which is often indistinct or even absent. 



The species is here described from the type Cat. No. 62241, U.S.N.M., 

 a specimen 96 mm. long from Tanegashima, where it is rather com- 

 mon in the tide pools. Examples were also taken nt Akune in Sat- 

 suma. Cotype is Cat. Xo. 21107, Stanford University collection. 



Genus XENISTHMUS, new. 



Body elongate, head pointed, lower jaw projecting. Tongue free, 

 rounded. Teeth simple, in a single row on jaws. Gill-membranes 

 extending forward below and uniting, their edges free from the 

 isthmus. Edge of shoulder girdle with a tooth. Head naked, body 

 with small cycloid scales. Dorsals separate; soft dorsal and anal 

 free from the caudal; ventrals separate, divided at the base. 



One species known, from Naha, Okinawa. 



Type of the genus. — Xenisthmus proriger, new species. 



XENISTHMUS PRORIGER, new species. 



I lend, measured from tip of upper jaw, 4.3 in length to base of 

 caudal; depth 6.5; depth of caudal peduncle 2.1 in head; eye 5; 

 snout 5; D. VI-14; A. 13; P. 15; scales in lateral series about 56; in 

 transverse series above anal 20. 



Body deeper than wide; head long and pointed; lower jaw pro- 

 jecting considerably beyond upper; maxillary extending to posterior 

 part of pupil. Tongue large, free, rounded at tip. Teeth simple, in 

 a single row on jaws,, none on vomer and palatines. Gill-membranes 

 extending forward below and uniting, their edges free from the 

 isthmus. Inner edge of shoulder girdle with a tooth covered by a 

 small dermal protuberance. Gill-rakers on first arch 3-!). long, 

 slender, and pointed. Anterior nostrils tubular; the posterior ones 

 with a large dermal flap. 



Head entirely naked: a row of minute dermal tubercles extending 

 backward from tip of maxillary along lower edge of cheek : a con- 

 spicuous mucous pore behind eye; 5 similar ones on top of head 

 arranged thus (:• ;). Body, including throat, breast, nape, and 

 bases of pectoral fins*, with slightly ctenoid scales of medium size, 

 which are largest on caudal peduncle. 



Dorsals separate, the first with slender spines about equal in length 

 to the rays, the longest (third and fourth) contained 2.5 in head. 

 Anal slightly higher than first dorsal, the longest (middle) rays 2.1 

 in head; first ray inserted below base of second dorsal ray; base of 

 fin not extending quite so far posteriorly as that of dorsal, the tips 

 of neither anal nor dorsal touching base of caudal when depressed. 



