Gren. 2. Astacilla.., Fleming. 
(Fncycl. Brit. 7th edit. Vol. VII). 
Si/non. Leachia, Johnston (non Lesueur). 
107 
Glen. 2. Astacilla, Fleming. 
(Bncycl. Brit. 7th Edit. Vol. VII). 
Synon. Leaclda, Johnston (non Lesueur). 
Slaegtskarakter. Legemet mere eller mindre lang- 
strakt, cylindriskt. 4de F orkropssegment stferkt forlsenget, 
10s Hannen meget smalt, hos Hunnen bredere og nedad 
ll d\ idet til Daimelsen af Brystposen. 2det Par F el ere 
^ ( 'd Svoben ganske kort, 3-leddet, saugtakket i den indre 
:int °g endende med en skarp Torn, lste Fodpar med 
•die Led brede og pladeformige, sidste Led ovalt og for- 
s ' l)( -d med en tydelig Klo. Brystposen kun dannet af 2 
valyelformige Plader tilhorende 4de Forkropssegment. 
Bemserkninger. Hvad der hovedsageligt skiller denne 
1 ,e £>G G'a loregaaende er Brystposens vsesentljg forskjellige 
igning, IForbindelse hermed staar ogsaa den uforholds- 
ffl.essige Udvikling af 4de Forkropssegment, der giver de 
'I' 1 l' en hurende Former et meget eiendommeligt Udseende. 
eu Johnston foreslaaede Slaegtsbenffivnelse Lea<Ma kan, 
s ’jfindt den liar Prioriteten tor Flemings, ikke bibeholdes, 
( a dette Navn allerede tidligere er anyendt i Zoologien, 
"einlig for en Cephalopodeslregt. Ikke faa Arter af nser- 
'•eiende Slmgt er beskrevne fra forskjellige Have, men de 
n ialmindelighed alle blevne henfprte under Slsegten Arc- 
turus. 
Generic Character. — Body more or less elongate, 
cylindrical. Fourth pedigerous segment ’ greatly produced ; 
in female broader, and, below, dilated — to form the marsu- 
pium. Second pair of antennae, with flagellum quite short, 
three-jointed, serrate along the inner edge, and terminating 
in a sharp spine. First pair of legs with all the joints 
broad and lamclliform, terminal joint oval and furnished 
with a distinct claw. Marsupium composed of only 2 valvular 
plates, belonging to 4th pedigerous segment. 
Remarks. — The character that principally causes this 
genus to differ from the preceding, is the essentially de- 
viating structure of the marsupium. In conjunction with 
this distinctive divergence, comes the disproportionate 
development of the 4th segment, giving to all the forms 
belonging to the genus a very peculiar aspect. The generic 
appellation Leachia, suggested by Johnston, though with a 
prior claim to Fleming’s, cannot be retained, that name 
having already been adopted in zoology, viz. to designate 
a genus of Cephalopods. Not a few species of the present 
genus have been described from specimens taken in various 
parts of the ocean; they have well-nigh all, however, been 
referred to the genus Arcturus. 
23. Astacilla granulata (Gf. 0. Sars). 
(PL IX, Fig. 27—35). 
je «c7ii a granulata , Or. 0. Sars, Prodromus descript. Crust, etc. No. <3 
(1S70). 
Lxcilla americana, Harger, Am. Journ. Sci. Ill, Vol. XV. pg. 374 
0878). 
s tacilia granulata, Harger, Report on the marine Isopoda of New 
England, pg. 304, PI. VIII & IX, Fig. 48—53. 
Artskarakteristik. Legemet hos Hunnen omtrent 7 
a.nge lsengere end bredt, oventil forsynet med talrige smaa 
undede Tuberkler. Hovedet oventil med en noget storre, 
'edelt Tuberkel. 4de Forkropssegment hos Hunnen ind- 
a g«nde mere end l j s af Totallmngden, noget udvidet fortil 
! )g P aa sin Overflade granuleret af smaa ensformigt udvik- 
^de Knuder; hos Hannen overordentlig smalt, cylindriskt. 
3 Pagre Forkropssegmenter med triangulmrt tilspidsede 
pinierer. Bagkroppen forholdsvis kort, med sidste Seg- 
®° nt kmi lidet udtrukket i Enden, oventil stmrkt knudret 
* '* d Basis forsynet med 2 triangulrere Sidofortsatser. 
23. Astacilla granulata (Gr. 0. Sars), n. sp. 
PI. IX, figs. 37—35. 
Leaclda granulata, Gr. 0. Sars, Prodromus descriptionis Crust, etc. 
No. 76 (1870). 
Astacilla americana, Harger, Am. Journ. Sci. Ill, Vol. XV, p. 374 
(1878). 
Astacilla granulata , Harger, Report on the marine Isopoda of New 
England, p. 404, PI. Vin & IX, figs. 48-52. 
Specific Character. — Body in female about 7 times 
longer than broad, furnished above with numerous small 
rounded tubercles. Head, above, with a somewhat large 
bifurcate tubercle. Fourth segment, in female, measuring 
more than one-third of the total length, somewhat dilated 
anteriorly, and, on its surface, granulated with small, 
uniformly developed protuberances; in male, remarkably 
slender, cylindric. The three posterior pedigerous segments 
with triangular-pointed epimera. Abdomen comparatively 
short, with the terminal segment but slightly produced 
toward the extremity; above, exceedingly rugged, and 
14* 
