460 Dr. Strahl on the Thalassine. 
group, but must decidedly be separated, as I will immediately 
show. Hitherto I have been unable to examine Azius sti- 
rhynchus and Glaucothoé Peroni in connexion with the existence 
or absence of the moveable scale. Should it prove that these 
species possess only the armiger, Avxius and Calocaris would 
probably have to be united ; for the latter has certainly no scale 
(see the figure in Bell’s ‘ British Crustacea,’ p. 233), and the 
other differences are not sufficient to support the division into 
two separate genera. 
That Gebia possesses no antennal scale is perfectly correct, 
although Dana thinks that his G. pugettensis might possess a 
scale. In G. barbata, described by me as new, the same struc- 
ture, however, occurs ; and I have pointed out that, great as the 
illusion may be, there is nothing but a fringe on the second 
joint, which, moreover, also occurs in G. littoralis. I have even 
seen a specimen of G. barbata, of which the left external antenna 
exhibited the fringe uninjured, while on the right side the hairs 
of the frmge were rubbed off, so that no one could be misled 
into the assumption of a scale. In the same way probably the 
fringe of G. hirtifrons, White, as figured by Dana, has been de- 
stroyed, and the fringe belongs to the general generic character. 
Consequently Gebia is throughout deéstitute of all trace of a 
scale, and G. hirtifrons does not constitute the type of a series 
of Gebie unfurnished with fringes. 
The new genus 77rypea is represented by Dana as allied to 
Calhanassa. The structure of the external maxillipeds and of 
the five pairs of feet, and the configuration of the abdomen, 
especially in regard to the appendages, certainly agree in the 
two genera; but- the eye-peduncles are different. In Trypea, 
according to Dana’s own drawing, these are cylindrical with a 
terminal cornea; but he expresses an opinion that they may be 
incorrect, as he could not make another comparison with nature. 
However, a further distinction is furnished by the structure of 
the outer antenna: as far as we can judge from Dana’s figure, 
this has neither squama nor armiger. Consequently the gap 
between Callianassa and Trypea would be greater than is stated 
by Dana. A second species, 7. porcellana, has been described 
by Kinahan (‘Journ. Roy. Soc. Dubl.’ i. p. 130, pl. 4. fig. 2), 
but this is probably only a Callianassa ; for, to judge from the 
figure, the flagella of the inner antenne are rather long, and 
certainly longer than their third joint, which is in opposition to 
Dana’s diagnosis; moreover he says of the eyes that they are 
sessile, but from the figure it is clear that they present the pecu- 
liar structure of Callianassa. The character of the external an- 
tenn cannot be determined with certainty from the figure. 
It is true that all Thalassinoidea have no branchie on the fifth 
