▁on ▁the ▁d ors al ▁mid line ▁behind ▁the ▁eyes , ▁separated ▁from ▁a ▁continuous ▁row ▁of ▁ 2 1 - 3 2 ▁median ▁tail ▁th orn s . ▁The ▁tail ▁is ▁moder ately ▁long , ▁narrow , ▁and ▁tap ering , ▁termin ating ▁in ▁a ▁small , ▁low - set ▁ca ud al ▁fin . ▁The ▁two ▁close - set ▁d ors al ▁fins ▁usually ▁have ▁an ▁inter d ors al ▁th orn . ▁Its ▁color ation ▁is ▁gray ish ▁pur ple ▁to ▁dark ▁ch oc olate ▁brown ▁or ▁black ▁above , ▁occasionally ▁with ▁scattered ▁small , ▁dark er ▁sp ots , ▁and ▁slightly ▁dark er ▁below ▁except ▁for ▁a ▁wh it ish ▁area ▁around ▁the ▁mouth . ▁The ▁anterior ▁tips ▁of ▁the ▁pel vic ▁fins ▁are ▁wh it ish . ▁Lar ge ▁males ▁have ▁irregular ▁wh it ish ▁bl ot ches ▁and ▁numerous ▁dark ▁sp ots , ▁while ▁females ▁have ▁reduced ▁or ▁absent ▁bl ot ches . ▁Ju ven iles ▁tend ▁to ▁be ▁uniform ▁in ▁color . ▁ ▁The ▁deep se a ▁sk ate ▁is ▁ov ip ar ous . ▁The ▁egg ▁cases ▁are ▁ob long ▁caps ules ▁with ▁st iff , ▁pointed ▁horn s ▁at ▁the ▁corners , ▁depos ited ▁on ▁sand y ▁or ▁mud dy ▁fl ats . ▁One ▁egg ▁case ▁measured ▁ 1 0 5 . 8   mm ▁long ▁and ▁ 6 5 . 2   mm ▁wide . ▁The ▁young ▁may ▁tend ▁to ▁follow ▁large ▁objects , ▁such ▁as ▁their ▁mother . ▁M ales ▁m ature