HY RIA. 
Puate IV. 

Species 7. (Mus. ?) (Copied.) 
Hyrra transversa. Hyr. testa oblongo-transversa, 
subtrigond, crassa, inequilateral, prope wmbones 
rugis crassis paucis impressa, intiis prope cardinem 
et medio salmoned, versus marginem ventralem 
ceruled ; latere postico obscure biangulato, latius- 
culo margine laterali obliquo ; latere antico anqusto 
brevi, margine dorsali cuneato; umbonibus 
tumidis. 
Tue Transverse Hyria. Shell oblong-transverse, sub- 
trigonal, thick, inequilateral, marked with thick, 
few wrinkles near the umboes; salmon-coloured 
within, near the hinge and in the middle, blue 
towards the ventral margin; posterior side ob- 
scurely biangular, rather wide with lateral margin 
oblique; anterior side narrow, short, with dorsal 
margin cuneated, umboes tumid. 
Hurk. Castelnau’s Expedition in South America, 
page 78, plate 15, fig. 1. 
Hab. Brazil, 
This shell, although smooth in every part except 
near the umboes, still has greater affinity with the 
rugose group than with that represented by Hyr. 
syrmatophora. 


Species 8. (Mus. ?) (Copied.) 
Hyria CasTELNAUDIL. 
trigond, saliduld, 
fused, intis subceruled ; latere postico maximo, 
Hyr. testa magna, inflata, sub- 
concentrice striata, olivaceo- 
radiatim rotundatim angulato, area postangulari 
elevatd, cuneatd, margine laterali obliquo; latere 
antico angusto, brevi, margine dorsali producto, 
acuminato ; umbonibus rotundis, subprominentibus. 
CasTELNav’s Hyria, 
rather solid, concentrically striated, olive brown, 
Shell large, inflated, subtrigonal, 
bluish within; posterior side very large, with a 

radiating rounded angle, postangular area elevated, 
cuneated ; lateral margin oblique; anterior side 
narrow, short, with dorsal margin produced, 
acuminated; umboes rounded, rather promi- 
nent, 
Hurf. Castelnau’s Expedition in South America, 
page 84, plate 16, fig. 1. 
Hab. Brazil. 
Diifers from Hyria avicularis in the great breadth 
of its posterior side. 


Species 9. (Mus. ?) (Copied. ) 
Hyrra comptanata. Tyr. testd solidd, trigono-sub- 
quadrata, medio complanatd, levigatd, olivaceo- 
fuscd, intis medio salmoned, prope 
ceruleo ; latere postico oblique angulato, latiori, 
margines 
margine dorsali recto, margine laterali concavo, 
margine ventrali rectiusculo ; latere antico breviori, 
angustiori, margine dorsal in alam parvam 
lanceolatam producto ; wmbonibus angulatis, haud 
prominentibus. 
THE FLATTENED HyriaA. Shell solid, trigonal, subqua- 
drate, flat in the middle, smooth, olive brown, 
within salmon-coloured in the middle, blue near 
the margins; posterior side obliquely angular, 
wider, with dorsal margin straight, lateral margin 
concave, ventral margin rather straight; anterior 
side shorter, narrower, with dorsal margin pro- 
duced into a small lanceolate wing; umboes 
angular, not prominent. 
Huré. Castelnau’s Expedition in South America, 
page 80, plate 15, fig. 3. 
Hab, Guayana 
A peculiar flatness in the centre of this shell, which 
is more characteristically shown in young specimens, 
distinguishes it from others. 
April, 1869. 
