ON BOSHINTD^, MACKOTHEICIDiE, ETC. 375 



1860. Lynceus macrourus, Leydig. Naturges. der Daph., p. 



219. PL IX, figs. 66, 67. 



1861. Alona elongata, G., 0. Sars. Om de i Omeg. af Christ. 



forekom. Clad., p. 19. 



1862. Alonopsis elongata, Gr. 0. Sars. Om de i Omeg. af Christ. 



forekom. Clad. Andet Bidrag., p. 41. 



1863. Acroperus intermedins, Schoedler. Neue Beitrage der 



Naturges. der Clad., p. 33. 



Carapace much elongated, somewhat oblong ; dorsal margin 

 gently and moderately arched ; posterior extremity obliquely 

 truncate ; ventral margin slightly arched, ciliated, a single mi- 

 nute tooth towards the well-rounded infero-posteal angle, where 

 the cilia cease ; surface obliquely striated, spaces between the 

 striae finely striated, these secondary striae having a direction 

 which is oblique to the course of the primary striae. Head 

 nearly erect, small, rostrum very short, well-rounded, hood- 

 shaped ; anterior antennae slightly longer than the rostrum. 

 Eye large, eye-spot nearer to the extremity of the rostrum than 

 to the eye. Abdomen long, of moderate breadth, parallel-sided, 

 supero-posteal angle rounded off, marginal spines about fifteen, 

 of moderate size, extending round the posteal angle ; terminal 

 claws very long and nearly straight, bearing three secondary 

 spines, one at the base, the second about the middle, the third 

 a little beyond the middle of the claw ; the space between the 

 first and second of these spines is also pectinated with (about 

 five) spine-like hairs. Length, infth of an inch. 



This species is easily distinguished by the peculiar sculpturing 

 of the carapace and by its elongated form, but more especially 

 by the presence of the three spines which spring from the ter- 

 minal claws of the abdomen, and which are very conspicuous 

 under the microscope. 



Gr. 0. Sars thus describes the male of this species — "Mas 

 femina minor marginem superiorem testae rectum, antennasque 

 primi paris aliquanto majores habet ; pedum primum par ungue 

 valde curvato armatum ; postabdomen apicem versus attenuatum 



