Wkigiit — Limnoithcrio : .1 Nnv Conchofitracan Oenun. 197 



ycuimd ;iiituiiii;i sLcjut, liiriuninis ; scapu sLidiig ami jiarlially .Sfi^iiieiiled. 

 Flagellac very long, sub-equal, with 15-20 joinl.s, sclose. Second antenna 

 very similar to that of Estheria. 



Mandibles sickle-shaped, wilbout palps. 



Trunk-limbs numerous, apparently coniparalilu l.o those in Estheria. In 

 males only one pair of trunk-limbs modified as claspers. 



Telson l^lstherian in type ; brnail caudal plate, witli Iwd denlaled lamellae, 

 terminating in two strong curved spines. Caiulal I'urcae claw-like. 



Hcinarhs. — The essential feature of this genus is the association df 

 Estherian characters in general with a single pair of claspers in the male. 

 The genus Cyclesthcria has this character, but appears to be so di.stinctive in 

 other features, such as details of structure of antennae and telson ami Ihi' 

 circular shell, that it is impossible to place the present forms in it. 



V. — Desci;iptiok of Type Species. 

 Limnestheria ardra sp. nov. 



Shell. — As seen in outline (Plate XXIV, fig. 1), the shell is oval 

 probably equi-valve, 5-6 mm. in length and o mm. high. The free edge of 

 the valve is delicately ciliated. 



The Budij and Us Appendages. — It is probable that in life the body could 

 be completely withdrawn inLo the shell, as in so many of the living 

 Gonchostraca. This conclusion seems justified by the relative magnitude of 

 the shell and body-parts (Plate XXIV, fig. 1). 



In the following description the body will be divided into three regions — 

 the head, the trunk, and the tail-segment. 



'fhe Head (Plate XXIV, figs. 1, la, Ic). — -In living forms the head region 

 bears three pairs of appendages — the antennulae or first pair of feelers, the 

 antennae or second pair of feelers, and one pair of mandibles or biting jaws. 

 The preoral region was not sufficiently well preserved to enable its details to 

 be described. 



In spite of careful search the antennulae were never found. It seems 

 more than probable that they were present, and if so they must have been 

 very simple in form, more of the nature of the antennulae of Limnadia, 

 Eulimnadia, Cyclesthcria and Limnadopsis than of those of Jiimnadella or 

 Estheria. 



Second Antennae {V\a,tQ XXIV, figs. 1 and Ic). — As is nsual in members of 

 this order, the second antennae are powerful, biramous, swimming and son.sory 

 organs. Each consists of a strong basal joint or scape (fig. Ic, sc, the 

 protopodite. showing imperfect segmentation, with wliicli are articulated two 

 many-jointed branches or rami. The two branches are practictiUy equal in 



