240 Horr & Beaumont—Survey of Fishing-grounds, W. Coast of Ireland, 1890-91. 
The above characters, if constantly found associated in individuals, would 
certainly enable us to name specimens either IL. flexuosa or M. neglecta, leaving to 
higher authorities the task of deciding whether or no the somewhat minute differ- 
ences enumerated were really of specific moment. However, in the Irish examples, 
the characters prove to be mixed in individuals or compromised by the occurrence 
of intermediate conditions. 
The number of joints in the tarsus has the appearance, on paper, of a well- 
defined character, and it may be easy for an expert to count the joints in all 
examples. We ourselves have often experienced the greatest difficulty in this 
matter, since the proximal articulation is often so faintly indicated, even under a 
moderately high power, that it is impossible to decide whether it is entitled to 
rank. Moreover, the number of joints often varies in the anterior legs of the 
same individual, as may be seen by the following figures :— 
Articulations of tarsus of legs, from in front backwards. 
Specimen. Specimen. 
A. 6, 6, 6, 5, 5, 4. I, & & @ & & & 
1, G& & GB & GB, 4 6 4-5 (??). 
ee - Yo 2H 2H ae HM), = (5) 
GO, &£666,a— eC : 
B 2 K. An anterior leg, 4. 
D. 5-6(?), x, =, 6, 6, 5 5 5 
6 Ih FB FA 2H 2H 5, 4, 
5-6 (?), a 6 
EB. 5, = 6, 5-6 (?), 5,4-5 (??). 
F. 5, 5-6(??), 5-6(?), 5, 5, 4. 
CoG O@) B@) & SM) & N. x, 5, a leg anterior to last 4. 
4 
M. 4-5 (?), 5, 5, 5, 5(?), 3. 
If the presence of a sixth articulation is a crucial point of distinction, A to J 
must be M. flexuosa, while Lto N are ML. neglecta. ‘The specimens are enumer- 
ated in the order of size, A to K measuring 24 to 15 mm. (including antennal 
scales and telson); L to M 13 to 12 mm. In the case of Schistomysis ornata, 
Norman, in deciding P. Kervilled to be a synonym of the first-named species, 
attaches no importance to the extra joint of the tarsus present, but apparently not 
invariably, in large specimens. We cannot see why the character should have 
greater value in Macromysis, in which, indeed, we have given some little 
evidence that the number of joints may increase with the age or size of the 
specimen ; although since M and N are fully developed males, it be not correlated 
to sexual maturity. 
+ Two figures separated by a hyphen and followed by a note of interrogation indicate that the exis- 
tence of the larger number of articulations (six in 5-6 ?) is doubtful. The doubt is greater where two 
notes of interrogation are employed. A single figure followed by a note of interrogation means that the 
proximal articulation was observed, but only indistinctly formed. Figures shown as fractions (2) refer 
to a pair of legs. 
