96 Account of a Journey across the 



claw, and the tarsus is broad with a diverging tooth. The 

 first pair of feet is much broader than the second. The fol- 

 lowing feet terminate with a long straight claw but slightly 

 curved in the form of a hook at the apex only, the three pos- 

 terior have merely a small foliaceous appendiculated member. 

 I did not see the branchiae at their base, but very distinctly 

 the three pairs of pseudo-abdominal feet, which consist of a 

 securiform, lamellar basal joint, and two articulated and ci- 

 liated spines ; so that there can be no doubt to which order 

 of Crustacea this animal belongs. The cibarian apparatus 

 seemed to me to consist of a marginated upper lip, a pair of 

 mandibulae provided with biarticulated palpi, three (?) or four (?) 

 pairs of lamellaceous maxillae, and two sex-articulated foot- 

 jaws. 



Plate III. Fig. 5. Chelura terebrans. 



a. The animal lying on its side, magnified four times. 

 h. The fourth and fifth caudal segment from above, as it a])pears 

 when it is magnified fifteen times. 



c. The same from below. The third pair of false abdominal feet 



is evident at the basis. 



d. The first foot seen magnified twenty-five times. 



e. One of the posterior feet with the same power. 



[To be continued.] 



XI. — Extracts from a few rough Notes of a Journey across 

 the Pampas of Buenos Ayres to Tucuman, m 1835. By 

 James Tweedie, Esq., addressed to Sir W. J. Hooker. 



[Continued from p. 1 5.] 



This morning, the 26th, we regained the post-road which we 

 had left at Pergamena, at 3 leagues beyond the post house of 

 Cabeza del Tigere, 320 miles N.W. of Buenos Ayres. Here the 

 tract turns more to the west, keeping along the east bank of the 

 Rio Corcouneon, a most delightful tract to behold, being finely 

 interspersed with woods of Algaroba and Chaiieos, the river gli- 

 ding on at the rate of about a mile in the hour, in a deep ravine 

 whose sides arc nearly perpendicular for 30 or 40 feet, espe- 

 cially the east bank where the sun is so powerful as to dry uj) 

 much of the vegetation, while on the west and north-west, 

 where it is shaded from the midday rays, the crooked course 



