190 Transactions. — Zoology. 



DESCRIPTION OF PLATE XXIIa. 

 Fig. 1. Cymodocea cordiforaminalis, from above X 13. 

 1«. ,, „ inner antenna X 30. 



16. ,, ,, outer antenna x 30. 



tc. „ „ first thoracic leg X 30. 



Id. , ,, abdomen from below X 24. 



Art. XVI. — On two Marine Mites. By Charles Chilton, M.A. 



[Read before the Philosophical Institute of Canterbury, 6th April, 1882.] 



Plate XXIIb. 



Among some Crustacea collected from Lyttelton Harbour I have found two 



specimens of mites, belonging to two different species. 



According to Semper,* sea-mites are " by no means rare." Grosse has 

 described three English species, one belonging to the genus Pachygnathus 

 (Duges) and the other two to the genus Halacarus, specially made for 

 them. As my specimens appear to resemble these two latter sufficiently 

 to be placed in the same genus, I have ventured to describe them. 

 Genus Halacarus, Gosse. 



(Annals & Magazine of Natural History, ser. 2, vol. xvi., p. 27.) 

 " Body covered above with a well-defined shield, either entire or trans- 

 versely sulcated ; under surface divided across the middle ; rostrum head- 

 like consisting of a bulbous tip, tapering to a point, divided longitudinally 

 beneath, allowing the protrusion of a pair of slender filiform mandibles ; 

 palpi terminated by a fang-like unguis ; feet cursorious, tipped with two 

 falcate ungues ; directed two forward and two backward, thighs remote. 

 Marine." 

 Halacarus parvus, sp. nov. PL XXIIb., fig. 1. 



Body oval, narrower in front than behind ; notched at the bases of the 

 legs, a slight transverse depression between the bases of the third pair of 

 legs, anterior margin between the bases of the first pah' of legs convex. 

 First two pairs of legs arising close together, third and fourth more remote 

 from one another. Legs subequal, third and fourth very slightly longer 

 than the first and second and with fewer setas ; all with the first two joints 

 short, third long and somewhat expanded, fourth short about as broad as 

 loug, fifth about as long as the third, last joint about two-thirds as long as 

 the fifth, bearing two very movable curved hooks, each of which has two 

 teeth at the end, the main one being larger and more curved than the 



* Animal Life (Inter. Nat. Sc. Series, vol. xxxi.), p. 433. 



