 The leopard catshark is the smaller and slimmer of the two Poroderma species . The head and snout are short and slightly flattened , with a somewhat pointed snout tip . Each nostril is split into tiny incurrent and excurrent openings by a three @-@ lobed flap of skin in front , of which the central lobe forms a slender barbel that reaches past the mouth . The horizontally oval eyes are equipped with rudimentary nictitating membranes ( protective third eyelids ) and placed rather high on the head , with a thick ridge running under each . The mouth is wide and arched , with short furrows at the corners extending onto both jaws ; the upper teeth are exposed when the mouth is closed . There are 18 – 30 and 13 – 26 tooth rows on either side of the upper and lower jaws respectively . The teeth have a narrow central cusp with a pair of small lateral cusplets ; those of adult males are slightly more curved than those of females . 
