2M TEN^TH AN^KUAL REPORT 



BOSMIifA CORNUTA. 



(Plate IX, figs. 3-5.) 



^Iq cni. long; shell reticulate with hexagonal meshes; antennae 

 curved backward and outward at the tip; claws with several teeth near 

 the base. In embryonic specimens the antennae are straight. 



BOSMINA STRIATA, Sp. n. 



(Plate IX, fig. 1). 



1^5 cm. long; shell marked with anastomosing longitudinal striae; 

 antennae very long; frontal seta about midway between eye and the 

 sense -hairs of the antennae : posterior inferior angle of shell spined as 

 in the previous species. 



The species resembles B. maritima greatly. The members of this 

 genus have been little studied owing to their small size and compara- 

 tive rarity, and it is even possible that some of the species will prove 

 invalid- 

 All three of the above species were found in one gathering from 

 Lake Minnetonka. Only one other locality (for B. longirostris) is known 

 to me in this State. 



LYNCODAPHNID^. 



Genus Macrothrix. 



Aside from M. roseus and M. tenuicornis (to which, perhaps, M. agilis 

 of a previous report may be referred) a single species of macrothroid 

 crustacean was collected at Lake Minnetonka, which is very remarka- 

 ble. The specimen was apparently somewhat injured in moulting, and it 

 is not possible to tell how much of its peculiar shape may be due to this, 

 fact, but some of its characters are sufficient evidence that it consti- 

 tutes at least a new species. 



It resembles in outline Simocephalas vetulus; the antennae are very 

 narrow and curved in a lateral as well as posterior direction; the 

 second or swimming-antennae are long as in other members of the 

 genus; macula nigra present but small; eye small; post-abdomen 

 short, triangular; claws pectinate; a dorsal sucking-disc is present; 



