53 CARBONIFEROUS ENTOMOSTRACA. 



Cytherella. n. Woodward, 1877. Catal. Brit. Fossil Crustacea, p. 109. 

 Brady, 1878. Trans. Zool. Soc, x, p. 407. 

 Terquem, 1878. Mem. Soc. Geol. France, ser. 3, vol. i, p. 194. 

 Bigsby, 1878. Thesaurus Devonico-Carboniferus, p. 249. 

 Brady, 1880. Report Ostrac, p. 171. 



Carapace bivalved, oblong or subovate, compressed, especially in front. Valves unequal, 

 thick, mostly plain and even, but occasionally raised in low undulations, ridges, or knobs ; 

 surface generally smooth, but sometimes pitted, reticulate, or granulose ; terminal 

 denticulations rare. Contact-margin of the right (larger) valve grooved or rabbetted on 

 its inner edge for the reception of a flange presented by the contact-margin of the left 

 (smaller) valve ; both groove and flange stronger at the posterior than at the anterior 

 portion of the valve. A small roundish depression near the centre of the valve externally 

 is represented within by a faint elevation or tubercle ; and in this the lucid spots are 

 arranged in a transverse, curved, pinnate, or plume-shaped series of from twelve to sixteen, 

 linear-oblong in shape, and usually increasing in length towards the ventral margin. 



Of the internal structure of the animal we have the following particulars, from the 

 observations of G. 0. Sars : 



"Antennas very large; the upper many -jointed, and geniculate at the base; the 

 lower broad and flattened, with a large pectinato-setose palp. Three pairs of hinder 

 limbs, scarcely pediform ; the two anterior pairs branchial, the others rudimentary. 

 Abdomen terminating in two very small, narrow, and spiniferous laminse." 



" Erom this definition of the genus," G. S. Brady observes, " it will be seen that it 

 differs very remarkably from all hitherto known forms, presenting in the conformation 

 of the lower antennas a remarkable approach to the Copepoda, and in the palps of the 

 mandibles and first pair of jaws a likeness to the Sidida. The way in which the animal 

 uses its powerful limbs is not known, it never having been observed in the living state." — 

 G. S. Brady, 'Trans. Linn. Soc.,' xxvi, p. 473. 



The following Synopsis of the known species, fossil and recent, arranged according to 

 date of publication, will be useful. The dates placed in parentheses belong to species 

 previously described. 



List of the known Cytherell,e and Bosquetia, arranged according to date of 



publication. 



[In many cases the species, and in some instances the genus, requires re-examination.] 



1830 Cytherella compressa {Of/there, Minister), Jahrb. f. Min. &c, 1830, p. 64. 



Tertiary. 

 1830 — ? inflata {Cythere, Minister), Jahrb. f. Min. &c, 1830, p. 65, No. 



17. Carboniferous. 



