107 



Gen. 2. Astacilla, Fleming. 



(Fncycl. Brit. 7th edit. Vol. VII). 

 Si/non. Leachia, Johnston (non Lesueur). 



Slægtskarakter. Legemet mere eller mindre lang- 

 strakt, cylindriskt. 4de Forkropssegment stærkt forlænget, 

 lins Hannen meget smalt, hos Hunnen bredere og nedad 

 ndvidet til Dannelsen af Brystposen. 2det Par Folere 

 med Svøben ganske kort, 3-leddet, saugtakket i den indre 

 Kant og endende med en skarp Torn. Iste Fodpar med 

 alle Led brede og pladeformige, sidste Led . ovalt og for- 

 synet med en tydelig Klo. Brystposen kun dannet af 2 

 valvelformige Plader tilhørende 4de Forkropssegment. 



Bemærkninger. Hvad der hovedsageligt skiller denne 

 Slægt fra foregaaende er Bryst]» isens væsentlig forskjellige 

 Bygning. I Forbindelse hermed staar ogsaa den uforholds- 

 messige Udvikling af 4de Forkropssegment. der giver de 

 herhen horende Former et meget eiendommeligt Udseende. 

 Den af Johnston foreslaaede Slægtsbenævnelse Leachia kan. 

 skjøndt den har Prioriteten tor Flemings, ikke bibeholdes, 

 da dette Navn allerede tidligere er anvendt i Zoologien, 

 nemlig for en Cephalopodeslægt. Ikke faa Arter af nær- 

 værende Slægt er beskrevne fra forskjellige Have, men de 

 er ialmindelighed alle blevne henførte under Slægten Arc- 

 turus. 



23. Astacilla granulata (Cl. 0. Sårs). 



(Pl. IX. Fig-. 'JT— :',.". i. 



Leachia granulata, Gr. O. Sårs. Prodromus descript. Crust. etc. No. 73 



[1876). 

 Astacilla americana, Harger, Am. Journ. Sei. III. Vol. XV. pg. 374 



(1878). 

 Astacilla granulata, Harger, Report on the marine Isopoda of New 



England, pg. 364, Pl. VIII & IX. Fig. 48—53. 



Artskarakteristik. Legemet hos Hunnen omtrent 7 

 Gange Lengere end bredt, oventil forsynet med talrige smaa 

 afrundede Tuberkler. Hovedet oventil med en noget større, 

 tvedelt Tuberkel. 4de Forkropssegment hos Hunnen ind- 

 tagende mere end l / 3 af Totallængden, noget udvidet fortil 

 og paa sin Overflade granuleret af smaa ensformigt udvik- 

 lede Kunder; hos Hannen overordentlig smalt, cylindriskt. 

 De 3 bagre Forkropssegmenter med triangulært tilspidsede 

 Epimerer. Bagkroppen forholdsvis kort. med sidste Seg- 

 ment kun lidet udtrukket i Enden, oventil stærkt knudret 

 og ved Basis forsynet med 2 triangulære Sidefortsatser. 



Gen. 2. Astacilla, Fleming. 



(Encycl. Brit, 7th Edit. Vol. VIL. 

 Sy non, Leachia, Johnston mon Lesueur). 



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 antennæ, with tiagellum quiteshort, 

 three-jointed, serrate along the inner edge, and terminating 

 in a sharp spine. First pair of legs with all the joints 

 broad and lamelliform, 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 eauses 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 tåken in various 

 parts of the ocean; they have well-nigh all. however, been 

 referred to the genus Arcturus. 



23. Astacilla granulata (G. 0. Sårs), n. sp. 



Pl. IX. fiss. 37—35. 



Leachia ■j,;<„,<l<,t,,. <;. ( ). Sårs. Prodromus descriptionis ('rust. ri,. 



No. 76 i 1876). 

 Astacilla americana, Harger, Am. Journ. Sei. Ill, Vol. XV. p. 374 



(1878). 

 Astacilla granulata. Harger, Report on the marine Isopoda of New 



England, p. Kil. Pl. VIII & 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, 

 unifornily developed protuberances ; in male. remarkably 

 slender, cylindric. The three posterior pedigerous segment-* 

 with triangular-pointed epimera. Abdomen comparatively 

 short, with the terminal segment but slightly produced 

 toward the extremity; above, exceedingly rugged, and 



14* 



