RECENT BRITISH OSTRACODA. 



457 



maj be employed to puncture tlie epidermis of algae, and afterwards to abstract the juices 

 of/the plant ; but in this case one fails to see any use for the exceptionally large poison- 

 ^ands and urticating setae with which the members of this genus are armed. Altogether 

 it appears to me more conformable to what we know of the general habits of the 

 Crustacea, and more fully explanatory of the peculiarities of the Paradoxostomata, if we 

 suppose their diet to consist of microscopic animalcula, rather than the juices of algae 

 or of animals much higher in organization than themselves. 



1. ' Paradoxostoma yaeiabilb (Baird). (Plate XXXV. figs. 1-7, 12-17, and Plate XLI. 

 fig. 8.) 



Cythere variabilis, Baird, Trans. Berw. Nat. Club, i. 98, tab. iii. figs. 7 a, b (1835), and ii. 153; Brit. 



Entom. p. 170, tab. xxi. figs. 10, 11. 

 Paradoxostoma variabile, G. O. Sars, loc. cit. p. 93. 

 ? Cythere flavida, Miiller, Entomostraca, p. 66, tab. vii. figs. 5, 6. 



British type. Distribution : Recent — Baffin^s Bay, Britain, Norway. Fossil — Glacial and raised 

 beaches, Norway, Scotland, Ireland. 



Carapace of the fema le, seen from the side, elongate-ovate, much attenuated in front, 

 highest behind the middle; greatest height equal to not more than half the length. 

 Anterior margin narrowly, posterior very broadly and obtusely rounded, often slightly 

 angulated above ; superior margin well arched, sloping rather steeply in front ; inferior 

 straight or but slightly convex in front, much more convex behind. Outline, as seen 

 from above, compressed ovate, tapering gradually to each extremity; greatest width 

 behind the middle, and equal to more than one-third of the length ; extremities pointed. 

 The shell of the male is similar to that of the female. Valves pellucid, white, slightly 

 olivaceous or ochreous ; marked with arborescent black or violet patches, and often with 

 two more or less distinct dark transverse bands. Second and fourth joints of the upper 

 antennae nearly equal in length, longer than the third, and very much longer than the 

 united lengths of the fifth and sixth. Terminal claws of the lower antennae very short 

 and subequal ; flagellum robust, triarticulate. Pirst pair of jaws having only three 

 uniarticulate lobes, two of which are nearly equal in length, the other more than twice 

 as long. Last joint of the third pair of feet very long and narrow, densely ciliated on 

 the anterior margin. Basal segment of the male copulative organs exceedingly large 

 and rounded, distal segment very small and twisted, bipartite, the anterior portion 

 narrow and obtuse, the posterior expanded and acuminate. 



Length 3^5— 3^ in. : - — 



Hab. Berwickshire and Dover {Dr. Baird) ; plentifully in rock-pools on the Northumberland and Durham 

 coasts, and in shell-sand from Guernsey (G. S. B.) ; at roots of Laminaria, Tobermory; Isle of 

 Skye, Arran, and Herm {Rev. A. M. Norman) ; Falmouth {Rev. Mr. Barlee) ; dredged oiF Cumbrae 

 {Mr. D. Robertson) ; Girdler Sand, Thames {Mr. E. C. Davison). 



It seems to me very probable that (as has been suggested by Sars) Miiller' s description 

 of Cythere flavida has been taken from the ochreous variety of this species ; but, con- 

 sidering the doubt which must attach to this supposition, and the fact that the name 



VOL. XXVI. 3 Q 



