Figure. Ventral view of a 90 mm ML mature male of H. reversa, off northeastern USA. Photograph by M. Vecchione.
Figure. Blow-up of the previous figure of H. reversa, mature male. Numerous dark, oval photophores have appeared on the mantle and head. The typical compound photophores are more difficult to see as most are covered by chromatophores. Photograph by M. Vecchione.
Figure. Photograph of a portion of one arm IV of H. reversa, mature male, off northeastern USA, same squid as above. The white arrows point to the typical four longitudinal series of compound photophores with those of the dorsal series being much the smaller. Numerous round photophores, lacking violet color filters and anterior, silvery reflectors, have appeared as the squid became sexually mature. Some of these are dark and completely covered by chromatophores while others have contracted chromatophores allowing the blue reflectors that back the photophores to be seen. Photograph by M. Vecchione.