(ii) E. cookei is not separable from E. brucus in its dimensions, external morphology or teeth, but is strikingly different in its dermal denticles which are numerous, uniformly distributed, small (not more than 4.0 mm basal diam.) and have deeply indented, angular bases and prominently ridged spins. In contrast, the buckler-like denticles of E. brucus are sparse, irregularly distributed, large (up to 15 mm or more basal diam. in solitary denticles but reaching to 35 mm in compound bucklers) with entire-margined bases and finely ridged spines. Adult E. cookei are also almost smooth under the snout and around the mouth, while in E. brucus these areas retain noticeable-sized denticles.

(iii) The Bramble Shark recorded off California by Hubbs & Clark (1945) as E. brucus is shown to be E. cookei. This confusion between the species, due to inadequacies in the earlier accounts of E. brucus, suggests the need for examination of other records of E. brucus. In this respect none of the five records of E. brucus from New Zealand are sufficiently definitive to allow confirmation as to species; but E. brucus is established as a member of the New Zealand fauna by the mounted skin of a Dunedin specimen in the Otago Museum.

(iv) Three juvenile specimens of E. cookei from Cook Strait are also described. These are markedly slender in comparison to the adult, and have one-cusped teeth as in Squalus. Their dermal denticles agree in relative size, spacing and distribution with those of the adult.

(v) The lateral line of juvenile and adult E. cookei is an open furrow from above the 2nd gill-opening rearwards. Its walls are supported by incomplete skeletal rings whose free ends project rearwards as spines along the edges of the furrow. In the adult the furrow is bridged at irregular intervals by narrow cross-connections of skin.

(vi) As the type of E. cookei is no longer in existence, the 1,980 mm male (Dom. Mus No. 2774) from Cook Strait is designated as the neotype of this species.