114: TWELFTH ANNUAL REPORT. 



Sp. 15. Pleuroxus (RypopMlus) uncinatus, Baird. 



The shell is ridged with lines running upward and backward, as 

 in P. bairdii; the lower angle of the shell has three teeth, and the 

 beak is more horizontal than in the above. In size and characters 

 this is almost identical with P. bairdii, with which it occurs in 

 England. 



This completes the list of swine-like members of the genus; these 

 well deserve to be studied from a morphological stand-point. 



Pleroxus nasutus^ Gay, is a poorly described form from Chili, re- 

 sembling, according to Schoedler, P. ornatus = tri2:onellus. 



A species of Percantha (Lynceus armatus. Gray) is found in Chili. 



NOTE TO PLEUROXUS.— The two species P. unideas and P. affinis are quite diverse 

 from the type of the genus and approach in some respects to Leptorhynchus. P. affinis, 

 particularly, has a recurved heak. I am in doubt about P. hamatus and P. acutirostris, 

 which is said to be reticulated ; but it seems likely that the species above mentioned 

 stand In closest relation to Leptorhynchus. 



Section B. Leptorhynchus^ Hernck.'^ 



The species for which Sars formed the genus Harporhynchus is 

 of Alona-like habit, but has a beak which exceeds that of any known 

 Pleuroxus in length, being simulated in this respect by the Amer- 

 ican P. acutirostris, which is, however, in other respects more nearly 

 allied to Pleuroxus. 



Leptorliynclius falcatus, Sars. 



Harporhynclius falcatus, sars. 

 Alona falcata, sars, p. e. mueller. 



Body oblong, arched above; ventral margin nearly straight, setose, 

 with a spine at the posterior angle; beak strongly curved, folded 

 laterally; pigment spot larger than the eye. The post-abdomen is 

 wide, sides nearly parallel, armed with a few strong teeth below 

 and a lateral line of spines; caudal claw with a single small basal 

 spine. 



VIII. — Genus Phrixura, P. E. Mueller. 



Oblong, wide; posterior shell-margin little less than whole hight. 

 Post-abdomen terete, obtuse at the end, which is armed with a 

 cluster of spines of which the terminal ones are similar to the others. 



1 Harporhynchus is preoccupied in ornithology. 



