54 
Rev. A. M. Norman on Crustacea Cumacea. 
VI.— Crustacea Cumacea of the 1 Lightning ,’ ‘ Porcupine ,’ 
and 1 Valorous ’ Expeditions. By the Rev. A. M. Nor¬ 
man, M.A. 
Order CUMACEA. 
Genus Diastylis, Say, 1817. 
( =Alauna , Goodsir, 1843.) 
1. Diastylis Bathkii (Kroyer). 
1841. Cuma Bathkii, Kroyer, Naturkist. Tidsskrift, vol. iii. p. 513, pi. v. 
figs. 17-30; id. op. cit. anden raekkes ii. 1846, p. 144, pi. i. figs. 4, 6; 
id. Voyages en Scandinavie &c. pi. v. fig. 1, a-u. 
1852. Cuma Bathkii, Lilljeborg, CEfversigt af Vet.-Akad. Forkandl. 
P- 6. 
1856. Diastylis Bathkii, Bate, Ann. & Mag. Nat. Hist. 2nd ser. xvn. 
p. 451, pi. xiii. 
1859. Diastylis Bathkii, Danielssen, Beretning om en Zoologisk Reise 
foretag. Som. 1857, p. 7. 
1864. Diastylis Bathkii, G. O. Sars, Om Cumacea, Chr. Vid.-Selskab. 
Forkandl. 1864, p. 35, and 1873, Om Cumaceen fra de store dybder i 
Nordisbafvet, Kongl. Vet.-Akad. flandl. Bd. ii. no. 6, p. 7, pi. iii. 
figs. 8, 9. 
‘Lightning’ Expedition, Station 3, lat. 60° 3P N., long. 
9° 18' W., 229 fathoms. ‘ Valorous ’ Expedition, Station 4, 
Davis Strait, lat. 66° 59' N., long. 55° 27 x W., 60 fathoms. 
This polar species is widely distributed in the Arctic and 
Boreal North Atlantic. I have seen it from Greenland, river 
St. Lawrence, N.E. America (New-England coast), Norway, 
Sweden, and Great Britain. 
Professor G. O. Sars has, I think, fallen into error* in 
supposing that Cuma angulata of Kroyer is the male of his 
C. Bathkii. Both sexes of D. Bathkii are alike in the spiny 
armament of the carapace, consisting of two longitudinal lines 
of spines, one on each side of the dorsal line; these spines are 
largest and widest apart just behind the rostrum, where the 
spines are also usually in pairs on each line ; the two lines 
gradually converge backwards, the spines rapidly decreasing 
in size, so as entirely to disappear at some distance from the 
hinder margin of the carapace. Among a collection of N.E. 
American Cumacea, for which I am indebted to Mr. L. I. 
Smith, is a Diastylis which I take to be the true Cuma angu¬ 
lata of Kroyer. 
* Beskrivelse af de paa Fregatten Josephines expedition fundne 
Cumaceer, 1871, pp. 5 and 21. 
