44 TRANSACTIONS, NATURAL HISTDKY SOCIETY OF CLASGOW. 



OccuuuENCE. — S. of Little Cumbrae, 14 fms. ; off Alans, 

 Cumbrae, 10 fms. ; off Aoidh Rock, Loch Fyne, 21 fms. ; near 

 East Loch Tarbert. 16 fms. ; Lamlash Bay, near King's Cross, 

 6-8 fms. ; Kilbrannau Sound, near Campbeltown, 18 fms. (S. of 

 Otterard Rock) ; Garrison Bay, Millport, 2-3 fms. 



Idothea viridis is a much smaller and slenderer species, oblong 

 linear in form. Without close examination it might be passed 

 over as the young of /. bcdtica, as the termination of the last 

 segment of the metasome somewhat resembles that species, but 

 the median prominence is much blunter, and the lateral corners 

 are obtuse ; the coxal plates are not contiguous as in /, baltica, 

 and are comparatively much smaller; the inferior antennae are 

 comparatively much longer and more slender, and the stylets of 

 the second pair of pleopoda in the male extend considerably 

 beyond the inner plate. 



Colour dark green, some specimens exhibiting a pale grey band 

 on the median line, extending from the middle of the cephalon 

 to the tip of the last segment of the metasome. Females bearing 

 ova in June, July, and August. Length of male, 10 mm. 



Occurrence. — Millport Bay, l.w. ; off Little Cumbrae, 8 fms. ; 

 Ettrick Bay, 7 fms. ; Minard Bay, 2-3 fms. ; Lamlash Bay, 4-5 fms.* 



I have been allowed to examine some specimens contained in 

 a tube in the Millport Marine Biological Station, belonging to 

 the " Robertson " collection, and marked " Idotea acuminata, 

 Leach." These are, however, referable to /. viridis (Slabber). 

 /. acuminata has now been transferred to a different genus 

 " in which all the segments of the pleon are dorsally fused, and 

 form a single piece." The late Dr. Robertson records this species 

 as having been taken by him in the Clyde, and Bate and 

 Westwood refer as having received specimens from that dis- 

 tinguished naturalist,! but in view of what I have stated above, 



* Since the above was read, my friend, Dr. Alex. Frew, of Glasgow, 

 has drawn mj' attention to the occurrence of this species at Langbank, 

 on the River Clyde, where I found it subsequently. At this spot the ebb 

 tide leaves a long stretch of mudflats, with small brackish pools, where I 

 took quite a number of specimens among the seaweed attached to 

 stones. They were much larger, however, than those I captured in the 

 firth, some measuring about 15 mm. in lengtli. 



t "History of the British sessile-eyed Crustacea, Vol. II., p. 395. 



