400 
MR. A. D. MICHAEL ON 
Clayagella minima, sp. nov. (PI. XXV. figs. 21, 22.) 
Testa parva, alba ; tuba longitudinaliter compressa, apertura leviter 
reflexa, baud fimbriata ; valva dextra lata, planulata, extus concentrice 
irregulariter rugata, intus argentea, margo dorsalis fere rectus, ventralis 
valde arcuatus. 
Valvse, umbonis marg. 7, antero-post. lOmillim. 
Hob. Mauritius (V. de Bobillard). 
This small Mauritian species is certainly distinct from the 
Maltese C. aperta, but it is impossible to say whether the speci- 
mens are full-grown or not. I have seen four specimens differing 
but little in size, two of which are in the National Collection at 
South Kensington. 
DESCRIPTION OF PLATE XXV. 
Fig. 1,2. Ovulum Haynesi, p. 397. 
3. Oliva Bulowi, p. 395. 
4, 5. Mitra formosensis, p. 395. 
6. Smithi, p. 396. 
7. reeurva, p. 396. 
8, 9. Trochus baccatus, p. 397. 
10, 11. Thalotia Wiliam, p. 397. 
12, 13. Amathina imbricata, 
p. 398. 
14, 15. Pleurotoma Briones, p. 395. 
Fig. 16, 17. Cochlostyla Gloynei, 
p. 398. 
18. Orthalicus MacAndrewi, 
p. 398. 
19. Crassatetta japonica, 
p. 399. 
20. Pectunculus crebrelira- 
tus, p. 399. 
21, 22. Clavagella minima, 
p. 400. 
On some unrecorded Parasitic Acari found in Great Britain. 
By A. D. Michael, F.L.S., P.Z.S., F.K.M.S. 
[Read 7tk February, 1889.] 
(Plate XXVI.) 
I spent the summer of 1888 in Derbyshire, near Chatsworth : 
the cold and wet season, however, rendered ordinary open-air 
collecting very fruitless ; I therefore took the opportunity of ob- 
taining all the wild mammals which I could obtain alive, or imme- 
diately after death, with a view to see whether I could find any 
unknown forms of parasitic Acari. My search was rewarded 
by finding the three species recorded in this paper, which, 
I believe, were not previously known. The Myocoptes adds 
another to this curious genus, which was founded by Claparede, 
and of which there was only one species known previously ; both 
are parasites of the mouse and rat tribe ; they are strictly ecto- 
