Introduction

Some species of Megalocranchia are very large and can reach 1800 mm ML, (Tsuchiya and Okutani, 1993). The vertical distribution is best known in M. fisheri. The paralarval stage, which reaches 40-50 mm ML, is spent in near-surface waters. Larger individuals occupy mesopelagic depths during the day and migrate into near-surface waters at night (Young, 1978).

Figure. Side view of earyl juvenile M. fisheri. Photograph by R. Young.

Brief diagnosis:

A taoniin ...

• with photophores on the digestive gland.