ORTMANN: CRUSTACEA OF SOUTHERN PATAGONIA. 651 



Distribution. Although a new species, some previous references might 

 possibly belong to it. As we shall see below, a locality from which Faxon 

 mentions H. dentata inermis, may belong to this species, namely : Puerto 

 Bueno, Smyth Channel, Straits of Magellan. The same form, H. inermis 

 has been mentioned by Wierzejski (1892, p. 187) from a stream that issues 

 from a lagune near Mendoza (northern Argentina), the water of which has 

 an odor of sulphur. However, what this form really is, remains to be seen. 



Cunningham (1871, p. 498, pi. 59, f. 14) mentions Allorchestes pata- 

 gonicus from a freshwater stream near Punta Arenas. He does not give 

 any description, since his single specimen was considerably injured, and 

 the figure is quite poor, and, no doubt, even incorrect. It is possible that 

 our species was intended, but we have no means of deciding this, and Al- 

 lorchestes patagonicits must remain a "nomen nudum." 



Description. Body rather robust, general form agreeing with that of//. 

 dentata inermis Sm. Eyes small, black, rounded, about twice their diam- 

 eter distant from one another. 



Antennulae longer than the stalk of the antennae, a little more than 

 half as long as the whole of the antennae. First and second joint of 

 peduncle of the same length, third a little shorter. Flagellum with 10-12 

 joints in the tf, and with 8-10 joints in the 9. 



Antennas about one third as long as the body, or even shorter. The 

 first joint of the peduncle short, the second a little longer, the third dis- 

 tinctly longer than the second. Flagellum with 12-17 joints in the tf, 

 and with 9- 1 4 joints in the 9. 1 



Maxillipeds (fig. 3, a) of the usual form, but all the joints are more 

 slender than in H. dentata inermis. 



First gnathopod of the cT (fig- 3, &} ' Meropodite with a blunt promi- 

 nence on the inferior margin, which is beset with a number of setae. Car- 

 popodite about twice as long as meropodite (measured from the middle of 

 the articulation with meropodite to the middle of articulation with propo- 

 dite), upper margin with a sharp spine near the distal end, which has a 

 group of setae ; lower margin with a very prominent, lobiform, rounded 

 projection, the margin of which is fringed with stiff setae. Propodite 

 almost triangular, almost as wide as long, and about as long as carpopo- 



number of joints of the flagella of both antennulae and antennae varies with age: it is 

 less in young individuals, greater in adults. Often the number differs on either side; this differ- 

 ence, however, is always slight, only amounting to one or two joints. 



