194 ■RECORDS OF THE AUSTRAMAX MUSKTM. 



Key to Australian genera. 



a. Soft dorsal with about 12 rays. Teeth vertical in lioth jaws, conical, and 

 sub-equal. 



h. Teeth uniserial in both jaws; scales small Periophthalnms. 



hh. Teeth biserial in the premaxillaries ; scales larger Periophthalmodon. 



aa. Soft dorsal with about 25 rays. Mandibular teeth more or less horizontal ; those 

 of the premaxillaries unequal, some subulate. 



c. Body scales small but distinct ; mandibular teeth arrauo;ed in a row wliich does 

 not curve inwards posteriorly lioleophthalmus. 



cc. Body scales rudimentary ; mandibular teeth in a row which curves inward 

 posteriorly Sea rtelaos. 



Periopiitiialmus, Block Si- Schneiiler. 



Periophthalnms, Blocli & Sclmeider, Syst. Iclitli., 1801, p. Go (P. papllio, 

 Bloch & Schneider). 



Eiichoristopns, Gill, Proc. Acad. Nat. Sci. Pliilad., 1868, p. HI (f,'ohiii.< 

 lioelretiteri , Pallas). 



Form moderately elongate, subcylindincal anteriorly, compressed 

 posteriorly. Body covered with small, cycloid scales, which extend onto 

 ihe head, Month rather small, horizontal, the upper jaw overhanging 

 the lower ; lips with fleshy lobes and swellings. Kyes erectile, contiguous, 

 on the upper profile of the head ; lower eyelid well developed. Anterior 

 nostrils opening in lobules above the upper lip ; posterior nostrils simple 

 openings before the eye. Teeth in a single row in each jaw, vertical, 

 conical, and pointed. Tongue thick, adnate to the floor of the mouth. 

 Gill-openings lateial, separated by a broad isthmus. Two dorsal fins, the 

 fii'st with spines varying in number up to fifteen ; second dorsal short, 

 with about twelve rays. Anal opposite and similar to the second dorsal. 

 Pectoral with a scaly muscular base. Ventrals more or less united or 

 wholly separate, with one spine and five rays. 



Small fishes of the estuaries and mud-flats of the tropical Indian and 

 Pacific Oceans, one species ranging northward to Japan. 



Perioi'HTHAL.mus KOELREUTEKi (Pallas), GUiither. 



var. argentilineatus, Cnvier ^V Valeiiciennes. 



(Plate xxxi., fig. 1.) 



Periophthahnits koi'lrentcn' (Pallas), Giinther, Brit. Mus. Cat. Fish., iii., 

 1861, p. 97. 



Periophthdliititfi anieiilil'mealus, Cuvier & Valenciennes, Hist. Xaf. Poiss., 

 xii., 1837, p. 191. 



D. xii-xvi/12-18; A. 12; P. 13; V. i/5 ; C. 15. Depth T) 7 i.i the 

 length to the hypnral joint ; head 4"2 in the same. Eye 4 in tlio head. 

 First dorsal spine 11, median dorsal ravs 2-1, median anal i:i\s 2-7 in tlu' 

 head. 



