250 Miscellaneous. 
described and illustrated by myself in 1874 (‘ Annals,’ vol. xiv. 
pp. 456 and 457, pl. xxi. fig. 27) was the same as that described 
and illustrated by Mr. R. Hope, F.Z.S., in February last (‘ Annals,’ 
vol. iii. pl. vi. A, 5) under the name of “Microciona spinarcus:” 
nor should I have perceived my error, had not Mr. Hope, in March 
last, kindly sent me preparations of yet another new species from 
Hastings, which, from the form of its tricurvate, we both recognized 
to be totally different from that of M. spinarcus ; at the same time 
it seems to me to be absolutely tdentical with my figure of 1874 
(1. c.), inasmuch as the arms of the latter are depressed almost 
to straightness, while in the former they are bent much upwards, 
bow-like (see Mr. Hope’s figure, J. c.). 
Mr. Hope’s second new species of Miecrociona, viz. that in which 
the arms of the tricurvate are so much depressed, will be described 
and illustrated by him hereafter ; meanwhile this statement will be 
sufficient to correct my own “ error,” and serve to record the exist- 
ence of an unnamed and undescribed British species of Microctona 
chiefly characterized by the form of tricurvate above mentioned. 
August 5, 1889. 
On the Marine Acarina of the Shores of France. 
By M. Trovessarr. 
Since my previous note on this subject communicated to the 
Academy on the 5th November, 1888, I have got together fresh 
materials which enable me to give more complete information with 
regard to the Acarological fauna of our shores. Besides my personal 
investigations I have received important contributions from MM. 
Chevreux and Le Sénéchal (of Croisic and Caen). Mr. G. 8. Brady 
(of Sunderland) has lent me the types of the species described by 
him from the English coasts. Lastly, Dr. Lohmann (of Kiel), who 
has just published an excellent monograph of the Marine Acarina of 
the Baltic Sea*, has taken the trouble to compare my types with 
his. 
The only truly marine Acarina are the Halacaride, which must 
form a very distinct family, and not a mere subfamily of the Trom- 
bidiide. In this latter family the last joint of the palpi is always 
palpiform, and it is the penultimate that acquires the form of a 
terminal claw ; in all the Halacaride, on the contrary, it is the last 
joint of the palpi which constitutes the terminal claw, and there is 
no trace of the palpiform joint. This fundamental difference seems 
to me to justify the elevation of the Halacaride to the rank of a 
family, as proposed by Murray in 1875. 
The Halacaride live in the sea from the littoral zone down to the 
depth of 30-50 fathoms. They walk and climb, rather than swim, 
upon the bottom, the rocks, the Algw, and the fixed or slow-moving 
* ‘Zoologische Jahrbiicher,’ Bd. iv. (1889) p. 269. 
