140 
Walter M. Tattersall. 
5. pleopods in the male but the vaulted form of the carapace, the 
elongate antennular peduncle, the short and narrow antennal scale 
and especially the form of the ocular lamina and the structure of 
the telson will, combined, serve to distinguish the species in coUec- 
tions. It would appear to be an abundant form in the Mediterranean 
at a depth of 1000 — 1700 metres (500 to 600 fathoms) and was, in 
ali cases, captured on the bottom. 
24. Mysidetes far vani (Holt & Tattersall). 
M. farrani^ Holt & Tattersall (1906). 
None of the specimens exceed 10 mm in total length but other- 
wise agree so well with Irish examples that I bave no hesitation 
in referiing them to the same species. As Norman (1892) points out, 
southern examples of a species are not infrequenti^ of smaller size 
than their more northern brethren. 
M. farrmii is now recorded from the Mediterranean for the first 
time. Though but recently described its distribution is already known 
to be extensive as besides the originai locality off the West of Ire- 
land it has recently been recorded from the northy side of the Bay 
of Biscay (Tattersall, 1908).^ 
25. Arachnoinysis leiickarti Chun. 
Ä. leuckarti, Lo Bianco (1901, 1903). 
Of this interesting and distinctive species 4 examples were 
captured during the cruises of the Maia and Puritan. 
Its known distribution so far confines it to the Mediterranean 
where it forms one of the characteristic features of the bathypelagic 
fauna and would appear to be by no means rare though captured 
usually in single specimens. 
26. Siriella norvegica? Gr. 0. Sars. 
S. clausii^ Lo Bianco (1903). 
It is with considerable diffidence that I refer the two specimens 
of Siriella to this species instead of to S. clausii under which name 
they were recorded by Dr. Lo Bianco. 
They differ from 8. clausii in havìng the median one of the 
3 small spines at the apex of the telson longer than the other 2, 
agreeing with S. norvegica and S. jaltensìs in this respect. The 
