6 
W. M. TATTERSALL. 
other respects the ‘ Discovery ’ material and the ‘ Challenger ’ types are in perfect 
agreement, and the facts noted above establish the identity of the females here 
referred to E. superba, with the species described by Sars as E. murrayi. It now remains 
to show that the differences between E. murrayi and E. superba are only sexual. 
Male. —Under the name E. superba Sars has described and figured this sex 
adequately. The only point in which his description is deficient is the structure and 
armature of the telson. He figures no dorsal spinules on the telson, and both describes 
and figures the apex as slightly produced and obtusely pointed. Examination of Sars’ 
type shows that the apex of the telson is clearly broken, so that Sars’ figure is in this 
respect entirely imaginary. In the present material the apex of the telson is much 
produced and acutely pointed, and the number of dorsal spinules is usually three pairs, 
but may be four or two, placed as in Sars’ figure of the telson of E. murrayi. One pair 
of spinules still remains in Sars’ type of E. superba, but the others had probably been 
broken off (or obsolete?). 
The most conspicuous difference between E. superba and E. murrayi, as described 
by Sars, is the presence in the latter and absence in the former of a lateral denticle on 
the carapace. But both Sars’ E. murrayi were females, and his single specimen of 
E. superba a male. In all the females in the present collection, the largest of which is 
47 mm. in length, the spine on the lateral margin is large and prominent, and even in a 
female, 50 mm. in length, in the collection from University College, Dundee, the spine 
is equally well-developed. I have figured the spine of the latter specimen on PI. I., 
Fig. 10. In male specimens, on the other hand, only those which are less than 42 mm. 
in length have the spine well-developed (cf. PI. I., Fig. 12, taken from a male, 39 mm. 
in length). In males above 42 mm. up to 47 mm. in length the lateral spine on the 
carapace is nearly obsolete and persists only as a blunt protuberance (cf. PI. I., 
Fig. 11, taken from a specimen 45 mm. long, and also Coutiere (1906), PI. II., Fig. 22, 
taken from a male of the same size). The ‘ Discovery ’ collection contains no male 
specimens exceeding 47 mm. in length, but the ‘ Challenger ’ type measures 48 mm. 
It is well preserved and shows no trace of the lateral spine at all. Obviously, then, the 
absence of a spine is a sexual character confined to absolutely full-grown males only. 
The remaining differences between E. superba and E. murrayi given by Sars are 
as follows:— 
(l) E. superba has the antennules considerably more robust than in E. murrayi 
and the lobe from the second joint almost obsolete. This difference is, I think, a 
purely sexual one, affording a parallel instance to that seen in the northern species, 
Nyctiphanes couchi. PI. I., Figs. 1 and 2 are taken respectively from male and 
female specimens of the same size, viz., 45 mm., and from the same bottle. They 
indicate, clearly, the difference in relative stoutness in the two sexes, and that of the 
male shows the lobe from the second antennular joint in an intermediate stage of 
reduction between that of the female and that shown by Sars in his figure of the male 
E. superba, 48 mm. in length. 
