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V, On the Crustacea Isopoda of the ' Lightning,' ' Porcupine,' and ' Valorous ' 

 Expeditions. By the Rev. A. M. Norman, M.A., D.C.L., F.L.S., and the 

 Rev. T. E. E. Stebbing, M.A. 



Received November 5th, 1884, read December 2nd, 1884. 



[Plates XVI. to XXVII.] 



Part I. — Apseudid^e, Tanaid^e, Anthuridjs. 



(jONSIDEEING the few hauls which have as yet been taken with the dredge at 

 depths greater than 1000 fathoms in the North Atlantic, it is surprising that by far the 

 larger number of families of the Isopodous Crustacea are already known to have their 

 representatives at this excessive depth, while many more were taken in the British 

 expeditions at such lesser though still great depths as a few years ago were almost 

 unassayed. 



The families which we now know to descend below 1000 fathoms are : — 



Apseudidae .... Genera Apseudes, Sphyrapus, 



Tanaidae Many genera, 



Anthuridae .... Many genera, 



Anceidae Anceus, 



Cymothoidee .... Cirolana, 



Idotheidae .... Chiridothea, 



Asellidae Nannoniscus, 



Munnidae Ischnosoma, Macrostylis, 



Munnopsidae .... Munnopsis, Ilyarachna, Eurycope ; 



and in the Southern Sea the Serolidse were found by the ' Challenger ' over a wide area, 

 descending even to 2040 fathoms. 



Apart, perhaps, from the Serolidse, the most interesting of the abyssal Isopoda are 

 those belonging to the families Munnidae and Munnopsidae. These are furnished with 

 antennae and legs of extraordinary length and delicacy of structure ; and, unfortunately, 

 the free use of sieves in washing the ooze on board the British expeditions resulted in 

 the entire mutilation of such specimens as were picked out from them, so that they 

 were for the most part little more than mere memberless trunks. 



We shall adopt in the following paper, as far as Tribes and Families are concerned, 

 the arrangement of the Isopoda which has recently been used by that prince among 



vol. xii. — part iv. No. 1. — October, 1886. o 



