508 TAOK SICOOSUKUn 



speciiuon, tho fijiuro is drnwn from tlio foiiuor specimen) a short luislle below and between 

 the two inner hristh's in tlie hnver row. The end elaw is powerful and about as long as the 

 anterior side of the two distal joints; il is rather weakly ])eetinate(l. 



Maxilla (fig. 9): — P r o t n p o d i t e: The distal eiidite has three bristles, the 

 middle one of which is somewhat shorter ihan the \\\'> otlicrs. The dorso-jMoxiuial bristle 

 is very short. The basale has one ventral bristle ol nioderate length. < 'n llir other hand 

 this joint has no short ventero-distal bristle or dorso-distal bristle. Endopoditc: TIh' 

 posterior distid bristle of the first joint is rather slightly more than half the length uf the 

 bristle of the end joint. 



Sixth limb (fig. 10): — This is very broad, with a broadly rounded postero-ventral 

 corner. It is quite different from all the other species of this genus dealt with in this treatise 

 because there are no posterior ventral bristles at all. On the other hand there are two anterior 

 ventral bristles and two bristles are developed on the anterior edge of the limb. Along the 

 ventral margin there are only close, fine, stiff, rather short hairs, of which those situated behind 

 the sinuosity denoted by a cross on the accompanying figure are distinctly more sparse, shorter 

 and finer than those in front of this sinuosity. The part behind the sinuosity seems to be thinner 

 and more hyaline than the anterior part. 



Seventh limb (fig. 11) : — This has ten cleaning bristles, of moderate and somewhat 

 different lengths; six of these are situated close together distally, three on each side, and four 

 are scattered somewhat proximally of the former, three on one side, one on the other. Each 

 cleaning bristle is armed with from two to four bells. Each end comb consists of from eight 

 to ten similar, weak, teeth, evenly and finely pectinated and strengthened into a somewhat 

 lancet-like shape distally. 



The f u r c a (fig. 12) has ten claws, of which the five anterior ones may be denoted as 

 main claws. The second to the fifth main claws differ somewhat in shape from the t}^e that 

 is usually characteristic of species of this genus, as they are considerably less bent, especially 

 the posterior ones. The two anterior main claws have no ventero-basal spines. The secondary 

 claws are not annulated. 



The lateral eyes are well developed. The median eye (fig. 13) has a few 

 short, fine hairs. 



The m ale is unknown. 



Material. Ronarks: — In order to verify by investigation the description of A. Mariae (W. Baird) 



I WTote to Professor G. S. BUADY for specimens of this species. A tube containing five specimens, 

 labelled A. Mariae in the writing of Professor BRADY, was kindly sent to me in answer to my 

 application. Even a rather hasty investigation of the shape of the shell was enough to show 

 me that among these individuals there were representatives of two quite distinct species. Four 

 of them, two mature females and two larvae, belonged to the species described by me above, 

 the remaining one was a larva whose shell certainly agreed in shape with that of A. Mariae 

 but which proved, on careful examination, to belong presumably to A. norvegica. (For A. Mariae 

 see the remark under A. Grimaldi var. vicina, pp. 518 — 522 of this treatise.) 



