Mr. P. H. Gosse on new or little-known Marine Animals. 27 



with a fringed border, the others plain. Anterior adductor muscle 

 larger than the posterior. Foot with a small flat sole, crenulated 

 at the edge, deeply grooved behind and byssiferous; pedal 

 muscles small in front, large behind, close to the adductors. 

 Palpi very small. Gills oblong, finely striated ; the outer ones 

 not quite so deep, furnished with a dorsal border, their free edge 

 grooved only in the middle. 



This remarkable shell, which resembles the Palaeozoic Modio- 

 lopsis in the large size of the anterior adductor, is found attached 

 by its byssus to floating weed in many parts of the Southern 

 Ocean. 



III. — Notes on some new or little-known Marine Animals. 

 By Philip Henry Gosse, A.L.S. 



[With two Plates.] 



(Fascis TI.*) 



Class ARACHNID A. 



Order Acarina. Fam. ORiBATADiE. 



Genus Halacarus (mihi). 



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

 transversely sulcated ; under surface divided across the middle : 

 rostrum head-like, consisting of a bulbous lip 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 ; di- 

 rected two forward and two backward ; thighs remote. Marine. 

 Name from aX?, the sea, and aKapi, a mite. 



Sp. 1. H. rhodostigma (mihi). Plate III. figs. 1-5. 



Body divided above and below ', claw of palpus slender, little 

 curved ; legs nearly equal ; thighs of first pair ventricose ; claws 

 of all simple ; whole surface minutely punctured. 



Description, — Length j^ndi of an inch from anus to tip of 

 rostrum ; colour pellucid whitish, stained with pale red on the 

 anterior half; above and below studded with punctures, which, 

 under a high power, take the form of rosettes (whence the specific 

 name, from poSov, a rose, and o-Tiy/j^r}, a point), or the spots on a 

 panther's coat (fig. 4) ; the punctures are conspicuous on the 

 first thighs, but are scarcely visible on the other limbs. The 



* Fasc. 1. appeared in the ^Annals' for August 1853. 



