IN THE NEST OF A MOLLUSC 381 
have no molar tubercle, and the ‘palp’ is very small, 
indistinctly two-jointed. The limbs are nearly as in 
Munna. The uropods are very short, two-branched, the 
branches simple, unequal. The Norwegian species are 
rubicundum, spinosissimum, and inerme, all instituted by 
Sars. Beddard has added two species from Kerguelen and 
one from Tristan da Cunha. 
Acanthomunna, Beddard, 1886, is akin to Munna, but 
the first antenne have a long instead of a short flagellum, 
and the limbs of the pereeon have the seventh joint simple. 
The type is Acanthomunna proteus from New Zealand. 
Leptaspidia, Bate and Westwood, 1867, has not been 
very fully described. The animal is said to be ‘ pear- 
shaped, flattened,’ but the latter epithet does not well apply 
to the ovigerous female. The pleon is oval, entire and 
almost acute at the apex. The limbs, except the first pair, 
are very slender, but not very short; they have the seventh 
joint simple. The uropods are minute, single-jointed, 
lateral. ‘The first pleopods are said to ‘ shut together in 
the form of a flattened pear, divided down the centre.’ The 
impression given by the figure is of a pair of valves as in 
the tribe valvifera. ‘This may be correct in regard to the 
male, but in the female there is a single opercular plate, 
slightly carinate down the centre. The type is Leptaspidia 
brevipes, from the Clyde, where this microscopic species 
was first found by Mr. David Robertson in the strange 
fibrous nests of the molluse Lima hians. It has no eyes. 
Neasellus, Beddard, 1885, is near to Pleurogoniwm and 
Paramunna in character, and in the articulation of the first 
antennz below the lateral extension of the head it re- 
calls the appearance of Leptaspidia. The first and second 
segments of the perzeon are dorsally fused in the middle ; the 
fourth and seventh segments are narrower than their neigh- 
bours. The type is Neasellus kerquelenensis (see Plate XIV.). 
Astriirus, Beddard, 1886, is much like Leptaspidia and 
Plewrogonium in appearance. ‘There appear to be traces of 
eyes. The fingers are not bifid. The uropods are rudi- 
mentary, yet perhaps two-jointed. The type is Astrurus 
crucicauda from the prolific vicinity of Kerguelen. 
28 
