IDOTHEA NEGLECTA WITHIN THE CLYDE AREA. 45 



there is just the probability of an error having been made in the 

 identification of the species by one or other of these zoologists. 



I. pelagica, Leach. — Some doubt evidently exists as to the 

 distinctness of this species. Thus, Rev. Thomas R. R. Stebbing, 

 in referring to flier's remarks on this family, observes : — " Idotea 

 marina (Lin.) is the name he adopts for that which Bate and 

 Westwood describe as Idotea tricuspidata, Desm., and /. pelagica, 

 Leach, and which has also been called by a dozen other names."* 



I have found this species frequently in many localities in the 

 Firth. A close examination leaves little doubt as to the dis- 

 tinctness of the species. The short and stout body ; the different 

 form of the terminal segment of the metasome; the greater 

 length of the stylets of the second pair of pleopoda of the male, 

 which extends much beyond the inner plate ; the small coxal 

 plates which are not contiguous ; the short and robust inferior 

 antennae make it impossible to confound with /. haltica. 



Occurrence. — L.w. near Inveraray ; off Davaar Island, 5-6 

 fms. ; off Sanda, 10 fms. ; off S. and Holy Isle, 6 fms. ; l.w. 

 Cumbrae; off King's Cross, Lamlash Bay, 2-3 fms.; Ettrick Bay, 



II fms. 



/. emarginata (Fabr.), though closely allied to /. neglecta, is 

 readily distinguished by the form of the last segment of the 

 metasome, which is abruptly truncated at the tip, with the lateral 

 corners projecting. 



Occurrence. — Lamlash Bay, 7 fms. ; off Blindman Rock, 

 Kintyre, 9 fms. ; Ettrick Bay, 9 fms. ; off Portincross Castle, 

 10 fms. 



(The late Dr. Robertson records having " taken it at l.w. among 

 seaweeds, Cumbrae.") 



/. linearis (Pennant). — This is also a readily distinguished 

 species. The terminal segment of the metasome is truncated at 

 the tip as in /. emarginata, but whereas in that species the body 

 is oblong oval in form, in /. linearis it is oblong linear. The 

 inferior antennae are of great length, reaching nearly to the end 

 of the metasome. The metasome occupies one-third of the entire 

 length of the animal. 



Length of male, 29 mm. ; of female (with ova), 17 mm. 



Females bearing ova in July and August. 



* " A History of Crustacea," p. 373. (Int. Sci. Series, Vol. LXXIV.) 



