162 



2 



- one specimen, — - — one specimen. 



We conclude from these formulae, tliat, like in the specimens 

 from the estuary of the Meuse, the formulae — , , — t — and — ~ — 



are those that most times occur. Also in other respects these 

 formulae agree with those of the shrimps from the iïollandsch 

 Diep, except the lower margin which is generally armed with 

 four teeth, in 3 specimens only with tJn'ee.) biit this may be a 

 fortuity. 



The general form, the length and the direction of the rostrum 

 with regard to the antennal scales is also the same : in specimens 

 of medium size the rostrum appears slightly longer than the 

 scales, in quite young ones, however, it reaches only their 

 extremity or rarely appears even a little shorter. 



In the females the fingers of the 2'i legs are a little shorter 

 than the palm or just as long as it, rarely the palm appears a 

 trifle shorter than the fingers; in the male specimens, however, 

 the fingers (Fig. Si>i) are, most times, miich longer than the jialin 

 and the carpus (Fig. SI) shows a someivhat stouter shape than in 

 the male specimens from the HoUandsch Diep. As results from 

 the foUowing Table, in which the measurements of the 2<i legs 

 of four males from the Flemish Pier near Antwerp are indicated, 

 the fingers are in N°. 1 almost one and a half as long as the 

 palm, but the other specimens form, as regards the length of the 

 fingers, a gradual transition to the specimens from the HoUandsch 

 Diep and the same transition-proportions are presented by these 

 specimens with regard to the stouter shape of the carpus. 

 The occurrence of so many male specimens with the fingers of 

 the 2<^ legs longer than the palm in the coUection from near 

 Antwerp may, of course, be a fortuity, but these longer fingers 

 are probably often observed in young or medium-sized specimens, 

 so that the rarity of such individuals in the coUections from the 

 HoUandsch Diep may probably be explained by the specimens 

 from that locality being almost all adult or nearly so. 



