740 DR WALTER E. COLLINGE. 



plates occupy the whole of the lateral margins of the second to seventh segments, 

 widening from before backwards. Maxillipedes (fig. 20) with elongated basal plate 

 and epipodite, distal inner lobe fairly large, no groove on the third joint of the palp. 

 Thoracic appendages (figs. 21 and 22) short and strongly built.* Metasome (fig. 24) 

 with two short segments and well-marked lateral sutures indicating a further 

 coalesced one, terminal segment with slight median ridge, lateral margins converg- 

 ing slightly to an obtuse point. Uropoda (fig. 25) rather broad, posterior margin 

 obliquely transverse, outer margin slightly curved inwards, endopodite terminally 

 obliquely truncate, outer margin converging a little towards the distal end, setose 

 style short. 



Length of <? 13-14 mm., of i> 9-10 mm. 



Colour dark brownish. 



Geographical Distribution. — Not a plentiful species in St Andrews Bay. I have 

 examples from Lowestoft, Boscombe, and Plymouth. Recorded from the Firth of 

 Forth ; Bell Rock (Bate and Westwood) ; Aberdeen (Scott) ; Firth of Clyde ; Port 

 Erin Bay (Hewitt) and South-West Ireland (Norman) : also coasts of Norway (G. 0. 

 Sars) and France (Bonnier). 



Remarks, — Although for long confused with /. baltica (Pallas), this is a very 

 distinct species, and there is no difficulty in at once separating both sexes from 

 the former species. 



(3) Idotea neglecta, G. 0. Sars. (PI. Ill, figs. 26-36.) 



Idotea marina, Bollfus, Feuille des Jewries Nat., 1895, p. 7, fig. 22. 

 Idothea neglecta, G. O. Sars, Crust. Norw., 1897, vol. i'i, p. 84, pi. xxxv, fig. 1. 



Idotea neglecta, Norman, Ann. and Mag. Nat. Hist., 1904 (s. 7), vol. xiv, p. 442; Tattersall, Nord. 

 Plank., 1911, p. 225, figs. 106-110. 



Body oblong oval, wider anteriorly than posteriorly. Cephalon (fig. 26) wider 

 than long, slightly emarginate anteriorly, posterior margin almost straight, pos- 

 teriorly with slight lateral clefts and dorsal ridges. Eyes rather large, situated 

 dorso-laterally, anterior to the median transverse line. Antennulse (fig. 27) extend- 

 ing to the end of the third peduncular joint of the antennae, first and second joints 

 expanded, third elongated ; flagellum single, rather long, clavate joint. Antenna 

 (figs. 28 and 29) of moderate length, peduncular joints gradually increasing in 

 length from the first to the fifth ; flagellum composed of eighteen to twenty joints 

 and short setose style. First maxillse (fig. 30), outer lobe terminating in eight 

 stout curved spines and three toothed ones ; inner lobe narrow, terminating in three 

 setose spines and a short spine on the outer side distally. The segments of the 

 mesosome (fig. 34) almost subequal, anterior angle of the first pleural plates directed 

 forwards, obtusely pointed. Coxal plates of male occupy the whole of the lateral 



* In the male there is usually a riense fringe of fine setae bordering the inside of the outer joints ; income cas?&, 

 however, these were not present, and no difference was observable from the condition obtaining in the female. 



