254 Transactions.—Zoology. 
Thinking that Mr. Kirk's specimens might possibly belong to the same 
species as those I had taken at Lyttelton I wrote to him about them, and 
in reply he very kindly sent me the three specimens for comparison. I 
have examined these as carefully as possible, and though they differ in 
some respects from my Lyttelton specimens and from Mr. Haswell's descrip- 
tion—approaching somewhat more nearly to P. cylindricus, Say—still I am 
convinced that they belong to the same species, and that although it is very 
near to P. cylindricus, Say, it is advisable to consider it as distinct until a 
comparison of actual specimens of the two ean be made. 
Mr. Kirk's three specimens were all very much larger than mine; the 
largest was ‘56 of an inch in length of body, while my largest specimen is 
only :12 inch ; Mr. Haswell gives the length of his specimens as “ about 1 
inch.” The inferior antenne, as in my specimens, and as shown in Mr. 
Haswell's figure, are about half the length of the body, not more ; in P. 
cylindricus they are ‘‘ more than half the length of the body." The length 
of the upper antenna compared with that of the lower varied somewhat. 
In the first specimen it reached to about the middle of the flagellum, in the 
second only to the end of the peduncle, in the third specimen the lower 
antenne were broken off. In my specimens also this character varies, 
usualy, however, the upper antenna reaches to the end of peduncle of 
lower; with regard to his specimens Mr. Haswell says :—** Inferior antenne 
stout, subpediform, with the peduncle equal in length to the superior pair.” 
All three specimens had the flagellum of lower antenna as long, or very 
nearly as long, as the last joint of peduncle; in my specimens and in Mr. 
Haswell's it is as long, and thus differs from P. cylindricus where it is 
** scarcely half the length of last joint of peduncle.” 
In Mr. Kirk's specimens, as in mine and Mr. HaswelP's, the spines found 
_on the end of the lower antenna are only somewhat curved, not hooked, as 
in P. cylindricus. The inner margin of the finger of the first gnathopod was, 
as in P. cylindricus, “serrated, almost pectinated ;” this is, to a less degree, 
also the case with my specimens of the male, in the female it is somewhat 
roughened only. The Wellington and Lyttelton specimens and Mr. Has- 
well’s agree in having the propodos of the second gnathopod longer than in 
P. cylindricus ; it is longer than the cephalon and first two segments of pe- 
reion. The finger in all has the inner margin smooth, in P. cylindricus it is 
‘coarsely serrated.” The finger has an enlargement on the inner margin 
near its base, in Mr. Kirk’s specimens the apex of this enlargement is 
rounded, in mine it is more pointed, and the enlargement is nearer the 
base of the finger; it is not mentioned by Mr. Haswell. My specimens 
agree with Mr. Haswell’s in having “a blunt tooth at the proximal and 
another at the distal end of the concave border” of the propodos of the 
