24T 



STATE GEOLOGIST. 



LYNCODAPHKiA, Gen. n. 

 (Plate IX, figs. 1-3.) 



Form much as is species of Alonella, etc., truncate behind; superior 

 antennae like Macrothrlx, attached movably to the end of a blunt 

 prominence beneath the head; second or swimming antennae slender; 

 four-jointed ramus with three long setae at the end of terminal joint 

 where is also a stout spine; joint following the basal joint also with a 

 spine above; middle joint unarmed (?); three-jointed ramus as in Ma- 

 crothrlx; the basal segment armed with a much elongated seta; eye rel- 

 atively small; pigment fleck present; intestine twice-convoluted, ex- 

 panded in front of colon, opening in the "heel" of the post-abdomen, 

 post-abdomen slender, sub-triangular, margined behind with a double 

 series of spines; terminal claws large, straightish and furnished with 

 a long and short spine near the base, also very minutely feathered be- 

 hind; shell marked alone by the so-called "stuzbalkein;" lower margin 



with movable spines. 



Few more interesting forms have been noticed than this, since it 

 combines the characters which have hitherto been considered as very 

 <jlearly forming the boundaries of distinct families. 



Kurz says, (Dodekas neuer Cladoceren nebst einer kurzen Uebersicht der 

 Cladocerenfauna Bohmens, p. 30:) "Keine Cladocerenfamilie bildet erne 

 so streng in sich abgegrenztes natiirliches ganze, wie eben die Lyn- 

 ceiden," and this even after recognizing the relationship of Macrothnx 

 andLdhonura to theLynceids by placing them in the sub-family Lyn- 

 oodaphnice. The form for which I propose the name Lyncodaphma is 

 quite as much like such forms as Alona- and related Lynceids, as any 

 species of the Lijncodaphnince, while at the same time the characters of 

 antennae and head are almost identical with Macrothrlx. This furnishes 

 but another example of the fact that possibility of distinguishing 

 families and genera lies alone in the meagerness of our knowledge. 



LYNCODAPHJ^IA MACROTHROIDES, Sp. U. 



Form sub-rectangular, greatly elongated; length iVo cm., hight 

 ,1, cm. or less; first antennae long and slightly curved, bordered be- 

 hind by about ten spines and terminating in two unequal sword-shaped 

 spines and several sense-hairs, about jH, cm. long; swimming an- 

 tennae very slender as in Macrothrlx, iSo cm. long; head not marked 

 off by a depression from the body, small and extending below into a 

 blunt elevation for attachment of antennae; labrum rather large; eye 



