CRUSTACEA OF ALABAMA. 7 



GENUS ACARTIA, Dana (=Dias, Lillg.) 



Body slender, especially the anterior segment of the thorax, which is obliquely sub- 

 truncate in front ; abdomen in the male five-jointed, the fourth joint being generally very in- 

 conspicuous, in the female three-jointed; antenna? not very long, twenty -jointed, nodose and 

 in the male slightly modified ; outer ramus of the antennule long and three-jointed ; la- 

 brum three-lobed; mandiblar palp rather small; maxillae with many hooked setae; maxilli- 

 ped as in Pontella ; feet with inner rami two-jointed, outer three-jointed; fifth feet one- 

 branched, in the female very small, bearing two setae, in the male prehensile. 



This genus was originally instituted by Dana, for four species somewhat like Pon- 

 tella, but, as the descriptions were of necessity rather meager and the limits of the genus re- 

 mained uncertain, a related form was found by Lillgeborg, in the North Sea, and called 

 Dias longiremis. This name, therefore, became generally recognized, but, as Giesbrecht 

 has shown, the specific application of later authors proves erroneous. The species of 

 this genus at present recognizable are A. longiremis, North Sea, A. bifilosus, North Sea 

 and Mediterranean, A. discaudatns, Giesbrecht, North Sea, A. laxa, Dana, Phillipene 

 Ids., Atlantic Ocean, A. denticormis .Brady (=? A. limpida, Dana,) Sandwich and Phil- 

 lipene Ids. 



Acartia gracilis, *P- «■ 



Dias longiremis ? Herrick, Twelfth Ann. Rep. State Geologist of Minnesota. 1884. 



The identification above quoted rested upon the correctness of Claus' identification. 

 He seems, however, to have figured A. bifilosus, Gies, which is much more closely allied 

 to our form. 



Body very slender for the genus, the anterior segment particularly long and much 

 narrowed anteriorly ; abdomen very short ; posterior segment of thorax rounded ; abdo- 

 men in the male five-jointed, but with the fourth segment often obscured, last segment 

 ornamented with spines, stylets about as wide as long, bearing five sub-equal setae ; an- 

 tennae twenty-jointed, extending to the last thoracic segment, very heavily spined ; feet 

 and mouth-parts with the usual characters ; fifth feet of the female as in A. bifilosis, 

 spermatophore as in A. longiremis. 



The material was unfortunately insufficient for a complete characterization so that 

 we are forced to resort to negative characters. The body is more slender than either A. 

 longiremis or A. bifilosus. From A. discaudatus it differs in the form of the spermato- 

 phore and and antennae as well as caudal stylets. The stylets are too short for A. lon- 

 giremis. The fifth feet of the male were seen only in immature specimens. From A. 

 laxa it is easily distinguished by the absence of spines upon the last thoracic segment 

 while the fifth foot of the female is very unlike that of A. denticornis. 



GENUS TEMORELLA. Claus. 

 The genus Temora was founded by Baird, to receive one of the Calanidee found 



