400 



MR. A. D. MICHAEL ON 



Clavagella minima, sp. nov. (PL XXV. %s. 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. 7j antero-post. 1 millim. 



Hah. Mauritius (V. de BoUllard). 



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. 



DESOEIPTION OF PLATE XXV. 



Fig. 1, 2. Ovulum Hay7iesi, p. 397. 

 3. Oliva Biilowi, p. 395. 

 4, 5. Mitra formosensis, p. 395. 



6. Smithi, p. 396. 



7. recurva, p. 396. 



8, 9. Trochus haccatus, p. 397. 

 10, 11. Thalotia Wilkics,p. 397. 

 12, 13. Amathina imhrieata, 

 p. 398. 



14, 15. PleurotomaBnoncB,^. 395. 



Fig. 16, 17. Cochlostyla Qloynei, 

 p. 398. 



18. Orthalicus MacAndrewi, 



p. 398. 



19. Crassatella japonica, 



p. 399. 



20. Pectunculus crehrelira- 



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., E.Z.S., F.E.M.S. 



[Read 7th 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- 



