Zoology.'] 



NATURAL HISTORY OF VICTORIA. 



[Fishes. 



Plate 87. 



MUSTELUS ANTARCTICUS (Gunth). 

 The Australian Smooth-Hound. 



[Genus MUSTELUS (Cuv.). (Sub-kingd. Vertebrata. Class Pisces. Order Plagio- 

 stomata. Sub-order Selachoidea. Fam. Carcharidse. Sub-fam. Mustelinae.) 



Gen. Char. — Form tapering, moderately compressed. Five small gill-slits, tbe three 

 anterior in front of pectoral. Two dorsals without spines, and moderate ventral and anal fins : 

 caudal moderate, extremity of body scarcely elevated, a notch in distal lobe ; basal lobes 

 moderate. Nostrils with a very long narrow triangular lobe from anterior edge, and a small 

 lobe from posterior margin. Mouth moderately arched, with strong prominent cartilages and a 

 deep fold about each angle. Teeth very numerous, small, rhomboidal, flat, like a tiled pave- 

 ment, of many alternate rows ; the posterior rows in some species with a slight short median 

 point, and one still smaller at one side. Spiracles moderate, a little behind and below the 

 posterior corner of eye ; eye elongate. A nictitating membrane. No pit in front of caudal. 

 Scales very small, triangular, tricarinate. Cosmopolitan.] 



Description. — Head semi-oval, -flattened, pre-oral portion about equal to the 

 width of mouth. Eyes approximate, lengthened with a thick fold below, forming* 

 the nictitating- lid, their anterior edges about as far from tip of snout as from each 

 other. Spiracle a little behind the eye. First dorsal small, entirely behind the 

 inner posterior lobe of pectoral, or very slightly in front of it, a little nearer to 

 snout than to the second dorsal ; anterior and postei'ior bases of anal a little behind 

 the corresponding parts of second dorsal ; space between doisals two and a half in 

 length of the base of second dorsal. Tail very slightly elevated j notch in distal 

 lobe of caudal fin deep and narrow. Color: Back and sides ashy-grey, with a 

 slight pinkish-brown tinge on side of head and bod}' ; with, from nape to second 

 dorsal, very small lighter spots on back and sides above lateral line ; lower lip, lower 

 third of sides, whole under surface of body, and under side of pectorals and ventral s, 

 milk-white j liind edge of dorsals and tip of caudal blackish; iris mottled green and 

 brown bronze, darker above and below. Teeth in about seven rows, the inner angle 

 slightly prominent as a very obtuse cusp on the inner rows. 



Measurements. small female. 



Ft. ins. lines. Ft. ins. lines. 



Total length to end of upper lobe of caudal ... ... 3 5 ... 1 11 



Length from snout to origin of 1st dorsal ... ... 1 1 ... 7 1 



„ of base of l.st dorsal ... ... ... ... 3 9 ... 2 6 



Height of 1st dorsal ... ... ... ... 4 ... 2 9 



Length of posterior lobe of 1st dorsal ... ... ... 1 7 ... 1 1 



„ from snout to anterior base of 2nd dorsal ... 2 3 ... 1 2 



„ of base of 2nd dorsal... ... ... ... 3 ... 2 



Height of anterior part of 2nd dorsal... ... ... 3 3 ... 2 2 



Length of posterior lobe of 2nd dorsal ... ... 1 2 ... 10 



„ from anterior origin of base of caudal fin to tip of 



upper lobe ... ... ... ... 6 4 ... 4 6 



„ from anterior base of 2nd dorsal to commence- 

 ment of caudal ... ... ... ... 7 5 ... 4 9 



„ of anterior edge of lower lobe of caudal ... 210 ... 2 



„ from snout to anterior base of pectoral ... ... 8 9 ... 4 9 



„ of base of pectoral ... ... ... ... 2 ... 1 .5 



„ of anterior margin of pectoral ... ... 5 ... 3 2 



[ 23 ] 



