40 ON THE AUSTRALIAN SPECIES OF PEN.EUS, 



joint, and another on the under surface of the third joint ; the 

 second pair with a single spine on the second joint. Abdomen 

 with well-marked carina on the fourth, fifth and sixth segments ; 

 the first, second, fourth and fifth segments with a notch on each 

 side posteriorly. Seventh segment strongly grooved on the middle 

 dorsal line, its apex spinif orm, its lateral margin devoid of spines. 

 Appendages of sixth segment rounded distally, the inner slightly 

 more pointed. 



Length of largest specimen 9 inches. 



Hah. Port Jackson ; Port Darwin. {Alex. Morton). 



This is the common edible prawn of Sydney, and Newcastle, etc. 



5. Penseus Macleayi sp. nov. 



Rostrum, extending nearly as far forward as the end of the 

 antennary scale, very slender and styliform near the apex, which 

 is recurved ; armed with five teeth above, of which the fifth is 

 separated from the fourth by an interval greater than that 

 separating the others ; unarmed below ; produced behind into a 

 low carina which broadens out and becomes lost before attaining 

 the posterior third of the carapace ; a lateral groove at the side of 

 the rostrum and the anterior part of the carapace. Grastro-hepatic 

 sulcus deep. Supra-orbital spine absent ; antennary and hepatic 

 spines present. Filaments of antennules sub-equal, scarcely 

 equal in length to the two last joints of the peduncle. External 

 maxillipedes slender, hairy ; palp extending as far as the middle of 

 the third articulation of the endopodite. First pair of ambulatory 

 legs as long as the antennary scale, very hairy internally ; second 

 and third progressively longer ; fourth shorter than third ; fifth the 

 longest of all, and very slender. First and second pairs each with a 

 spine at the base of the second joint. Abdomen having the fourth, 

 fifth, and sixth segments dorsally carinated ; carina ending in a 

 small spine at the posterior border of the sixth segment. Terminal 

 segment longitudinally grooved in the middle dorsal line, ending 

 in a spiniform apex, ciliated laterally, and armed on each side 



