No. 484] DISTh'lllCTfoX OF (11 .KT< HiXATHH 247 



forced to depend >M\ stiuctiiral tv.s(>iiil)lances for the 



determination of sjxM'ilic rrlationsliips. 



The s])e('ies of ^auiiia aiv distinouislicd, anion^ other less 

 quantitatively ('N])Itssc(1 cliaracters, by (1) size, (2) ratio of tail to 

 total leno'ili. (.{) miinlHT of jaws, (4) number of anterior and (o) 

 posterior tivtli. An analysis of Fowler's (:0()) specific diagnoses 

 reveals three t,n-ou])s of related s])ecies within wiiich couplets of 

 most closely related species may be noted. 



The first of these, the srrratodoitata otouj), includes five species: 

 S. serratodentata, a eurythennal cosmopolitan s|)t>eie> with little 

 tendency to sink to deeper waters in tlie tropics; .S. Ixdoli, a 

 neritic surface species from Indo-Austral waters; N. /criKv and 

 <S. rohuMa, neritic and surface species from the Malay and Maldive 

 Archipelagos; and 8. siboc/w, taken only in hauls from dee{) water 

 in the Malay Archipelago. 



The following table of cjuantitative characters of the species 

 taken from Fowler's records serves rather to indicate their close 

 reseml)lance than to dilferentiate them. Other characters such 

 as proportions, form of the (yes and teeth, assist in dia^mosis. 



sibogce 9-20 21-83 



ferox l()-2() 29-36 r,-G 



