24 Notes on the Irish Crustacea. 
Genus Inachus, of the three species dorhynchus, is the most 
rare of those alluded to by Thompson in his list of Irish crus- 
tacea, as he does not appear to have collected it. In the papers 
read before the Natural History Society of Dublin by Professor 
Kinahan, both species are mentioned as common on the Dublin 
and Galway coasts, and in Belfast Bay. Inachus leptochirus is not 
given in any of Kinahan’s lists, neither have I met with it on the 
south-west coast, though the other two are frequent. A beautiful 
specimen of Machus dorhynchus, I have taken in deep water, of 
a light yellow, the carapace and fore-legs spotted with a dark 
sponge. William Thompson mentions I. leptochirus to have been 
dredged in Clifden Bay, Connemara. Both species, dorsettensis 
and dorhynchus, inhabit deep water, and both, according to the 
soundings, are found marked and coated with fungoid colorations, 
and small fuci, and zoophytes. In the examinations of numerous 
specimens scarcely any appreciable differences can be sustained. 
In dorhynchus, the margins of the shell being destitute of 
tubercles, and the hands smooth, would seem the only distinctive 
separations from dorsettensis, characters in the crustacea, by no 
means tenable. 
Pisa (four horned spider crab) the next genus, species are des- 
eribed as presenting variations of form and structure, separating 
tetraodon from that of Gibsii, still there are such apparent con- 
nexions, that there are difficulties in sustaining characters which 
are not more or less common to both. The females are more closely 
allied in the defined form of the rostrum, the less spinous state of 
the lateral margins of the carapace, and the smaller proportions 
of the fore-legs. ‘The spine described on each brancial region in 
Gibsw, cannot maintain decided distinction, as shown in the genus 
Gonoplax. Both species are subject to the growth of alga, and 
zoophytes covering the carapace and legs, more so in Gibsii, from . 
the dense villous coat of the carapace favouring attachment. The 
specimen submitted is more characteristic of Gibsii than of 
tetraodon, and may be considered as the arctopsis lanata of 
Lamouroux—Pisa Gibsii of Leach. It was obtained in twenty- 
tive fathoms off Innisnabroe Island, coast of Kerry, and now first 
presented as Irish, The only specimens in the Museums of Dublin 
were obtained at Roundstone, Connemara, first discovered by the 
late William M‘Calla, the species being tetraodon. William 

