256 Zoological Society : — 



The superior antennae have the basal joint of the peduncle broad 

 and much hollowed to receive the eye, and its inner border carries a 

 short lamellar appendage. Each has two filaments with thickened 

 bases, of which one is nearly twice as long as the other, and the 

 longer has a length nearly equal to that of the carapace exclusive of 

 the rostrum. The basal joint of the inferior antennae is short and 

 thick, and it has a small emargination in front on the upper side. 

 Their palps are large, extending very nearly as far as the rostrum, 

 and they are shaped like the quarter of an elongated ellipse ; but 

 the thick outer margin curves slightly inwards, and projects in front 

 as a short tooth. The inner margin is fringed with hair. The fila- 

 ment is longer than the total length of the Crustacean, including the 

 rostrum. 



All the feet are slender, and the first three pairs are two- fingered, 

 with ovate hands, the rest being monodactyle : none are multiarticu- 

 late. The order of their length, commencing with the longest, is 

 5, 4 = 3, 2, 1 ; the third and fourth pairs reach beyond the eyes ; 

 the first pair has a fringe of hair at the under edges of all the joints, 

 and the second and third joints each carry a spine at the distal ex- 

 tremity of the underside. The first pair of pedipalps is long, slender, 

 and pediform ; they extend beyond the eyes. 



The abdomen is subcompressed in front, much compressed behind, 

 and the anterior five segments are furnished with large and promi- 

 nent false feet, each terminated by a pair of narrow flexible plates 

 fringed with hair, of which the outer one is longer ; the basal joint 

 is shorter than either. All the segments have their inferior margins 

 fringed with hair. The fourth, fifth, and sixth segments possess a 

 median keel, which terminates posteriorly with a small sharp tooth ; 

 and the sixth segment has in addition a small tooth at each posterior 

 angle. The posterior margins of the fourth and fifth segments have 

 a small notch at the middle of each side. The seventh or caudal 

 segment is about as long as the sixth, which is longer than any of 

 the preceding segments ; it is narrow, terminates in a point, and is 

 armed with a small spine at each side near the posterior extremity. 

 The lateral plates are narrowly oval and fringed with hair ; both 

 pairs extend beyond the seventh abdominal segment, but the outer 

 plates are larger than the inner, which latter have a longitudinal me- 

 dian groove on the upper surface between two low crests. There is 

 also a groove on the upper surface of the exterior plates ; but it is 

 not in the median line, and it terminates at the outer margin not far 

 from the posterior extremity of the plate. At this place there is a 

 small sharp tooth, and here commences a low crest which crosses 

 the plate with a curve and divides it into two unequal portions. The 

 common basal joint of these plates has a small sharp tooth at its 

 postero-exterior angle. 



Large quantities of this Penceus are taken at the mouth of the 

 Tagus during the spring and summer months ; and it frequently 

 appears on the breakfast-tables of the hotels in Lisbon, where indeed 

 it first attracted my attention. It is known in the market under the 

 name of " Camarao," i. e. Prawn. The living Crustacean has a pale 



