Report on the Crustacea Schizopoda of Ireland. 238 
The species is added to the British Fauna on the evidence of a single female, 
so much battered that some of the generic characters cannot be observed. ‘The 
telson, however, remains available, and is of a form only met with, so far as we 
know, in the genera Parerythrops and Metererythrops (v7de figs. 2, 3). 
In distinguishing between the three known species, P. obesa, M. robusta, 
S. I. Smith, and P. abyssicola, G. O. Sars, the small size of the eyes in the last 
named is a very obvious character. The two first have large eyes of about the 
same size and form. So far as we can determine, in the absence of the adjacent 
appendages, and from the defective condition of the cephalothorax, the eyes in 
our specimen are too large to permit of its being assigned to P. abyssicola. 
Moreover, the outline of the facetted area agrees, on the testimony of Sars’ figures, 
rather with P. obesa than with P. abyssicola. While in other characters the latter 
closely resembles P. obesa, M. robusta differs from either in haying a much more 
elongate telson. In our specimen it is about equal to the last segment of the 
abdomen; in M. robusta it is about one-third as long as the entire pleon. Minor 
differences observed by Sars in the characters of the antennules, antennal scales, 
and legs are of no use to us, as our specimen has lost all these appendages. 
P. obesa and P. abyssicola are not separated by any very well-marked charac- 
ters of the telson, but, although the lateral margins of this structure are rather 
more curved than in Sars’ figure of P. obesa, they agree with that species rather 
than with P. abyssieola. The proportions of the terminal spines are also in 
harmony with P. obesa rather than with P. abyssicola (cf. Sars, op. cit., Pl. ul, 
111%, 1G), IAL, SOXMilip Tes Op WO, JBL soso, wes, TS) 
The single inner uropod which remained entire in our specimen was broken 
in manipulation, but has been carefully reconstructed by Mr. Green (fig. 3). 
At present it has fewer spines than in any of Sars’ species, but some have almost 
certainly been broken off. 
Genus Mysidopsis, G. O. Sars. 
Mysidopsis didelphys (Norman). 
Survey.—Station 115. Off the Skelligs, 62 to 52 fathoms, mud and sand. 
August 20th, 1890. 
Station 125. 40 miles west of Bolus Head, 115 fathoms. March 23rd, 1891. 
We have already mentioned, under LZ. serrata, the accidental mixing of the 
contents of the bottom and surface nets of Station 125. The bottle contains a 
mangled specimen, apparently a Mysidopsis, and probably referable to this 
species. The total length is about 7 mm. The cephalo-thoracic shield is 
displaced ; the trunk is much macerated; the legs have disappeared, except the 
