ORTMANN: CRUSTACEA OF SOUTHERN PATAGONIA. 655 



4. In our species, the meropodite of the second gnathopod of the '$ 

 has a triangular, pointed prominence on the lower margin, while in H. 

 dentata and inermis this process is blunt and obtuse. 



5. Size of our species much larger, up to 16 mm., while H. dentata and 

 inermis measure not more than 6 mm. 



Thus we see that H. patagonica differs from H. dentata, and especially 

 from H. inermis, in some slight and unimportant features of the antennulae 

 and antennae, and in some very marked characters of the first and second 

 gnathopods of the $ and 9, and in size. Nevertheless, these three forms 

 seem to be very closely allied in the general shape of the body, length of 

 antennulae and antennae, and the general shape of the chelae of the second 

 gnathopods of the J 1 . 



It remains doubtful, whether Faxon's H. dentata var. inermis from 

 South America is really identical with the form of the United States. 

 Faxon says that his Lake Titicaca specimens exhibit some differences in 

 the shape of the propodite of the second gnathopods of the cT, but his 

 figure does not reveal them in a sufficient degree. Considering the fact 

 that we possess several hundred individuals of our species, and that they 

 all show a great uniformity in their characters, and that the differences 

 mentioned above are constant among them, it is possible that also the 

 Titicaca form of which Faxon had only 6 specimens might be a good 

 species. As to the specimens from Peru and the Straits of Magellan, 

 Faxon does not give any details of their characters, but I suspect very 

 strongly that those from the latter locality really belong to our species. 



H. dentata var. gracilirostris (Fax.) from Brazil differs at once from all 

 others, discussed so far, in the much longer antennae, which are half as 

 long as the body. There may be other characters that differ, to which 

 Faxon does not refer. He had only one female. 



H. longistilus (Fax.) from Brazil differs at once in the third uropods, 

 which are much longer, and in the longer antennulae and antennae. Car- 

 popodite of second gnathopod of J 1 more oval, and less distinctly triangular. 



H. jelskii (Wrz.) from Peru differs: 1 



i. Antennulae and antennae much longer, and the antennae of the <$ 



l Wrzesniowsky does not give any figures of his species, and consequently we cannot form, 

 in some points, a good idea as to their characters. Nevertheless his descriptions are generally 

 clear, and do mention characters that show conclusively that his species are different from H. 

 patagonica. 



