IRISHES OP THE iPSlLlPPliirE ISLANDS AND ADJACfiNT SEAS 67 



A large family of oviparous or viviparous sharks, variously pe- 

 lagic, some bathypelagic or littoral. Their food is largely marine bot- 

 tom dwelling animals, especially invertebrates and fishes. Most are 

 of small size in the Indo-Pacific, a few in the Atlantic. Several 

 reach upward of 12 or more feet. Several features of divergence in 

 adaptation are noteworthy. Thus the nurse sharks {Ginglymos- 

 toma) like other pelagic forms are of nearly uniform coloration. 

 The wobbegongs {Orectolohus) are bottom forms variously mottled 

 and many with skinny flaps, living among weeds and rocks, some- 

 what suggestive of the so-called angel sharks {Squatina). Other 

 forms, as species of Stegostoma and HeTniscyllium, are brilliantly 

 contrasted when young, though they become more subdued or uni- 

 form with age. Tropical littoral forms {HemiscylliuTn, Brachae- 

 lurus, ChiloscyUium^ Stegostoma) are strikingly barred, spotted, or 

 variably marked, often in great contrast. 



ANALYSIS OF GENERA 



a\ Spiracles very small ; anal distinct or well separated from caudal, opposite 

 or before second dorsal. 

 6\ Nebriinae. Gill openings subeqvial ; second dorsal origin above or before 



anal Nebrius 



6^ Parascyixiinae. Last gill opening largest ; second dorsal origin behind 

 anal origin or even behind anal base. 

 c\ Short barbel on throat ; second dorsal over last half of anal length. 



Cirrhoscyllium 



c^ Throat without barbel; second dorsal behind anal Parascyllium 



c'. Spiracles large ; anal close to subcaudal or only separated by narrow notch, 

 behind second dorsal. 

 d\ Spiracle below level of eye ; caudal usually short, not over % total 

 length. 

 &. Hemiscyluinae. Teeth similar, small, tricuspid, arranged in many 

 series; head without dermal lobes. 

 f. Tail short, not over % longer than combined head and trunk ; 



ovoviviparous Brachaelurus 



f. Tail long, not less than i/^ longer than combined head and trunk ; 



oviparous Hemiscyllium 



e^ Oeectolobinae. Teeth unlike in jaws, in front long, slender, and 

 smooth, laterals small, tricuspid and in few series; sides of head 

 and snout with more or less interrupted rows of dermal flaps ; 



ovoviviparous Orectolobus 



d^. Stegostominae. Spiracle behind eye ; caudal i^ or even slightly over 

 % total length ; coloration variegated, young with contrasted numer- 

 ous black cross bands Stegostoma 



Genus NEBRIUS Ruppell 



Nebrius RtJppEax, Neue Wirbelth., Fische, p. 62, 1835. (Type, Nehrius concolor 

 Riippell, monotypic.) (Nebria Latreille and Nebris Cuvier not involved.) 



G in ijlynio stoma MiJiXEB and Henle, Sitz. Ber. Akad. Wiss. Berlin, 1837, p. 113. 

 (Type, Squalus cirratus Gmelin, Arch. Naturg., 1837, p. 396 : Designated 

 by Hay, U. S. Geol. Surv. Bull. 179, p. 310, 1902.) 



