60 I'lIVI.I.OI'OD CKl'-STACEA 



with slight notch in 1st ])air: nearly straight in 2nd; "tluiinl)" sqnare in 1st pair, slightly 

 broader in 2nd; in both pairs base of spinous patch of thunil) only slightly longer than the 

 spines. Last 15 (about) segments armed dorsally (spine- formula of type, from behind for- 

 ward: 1, 1, 3, 3, 3, 4, 4, 5, 5"^ 5, 5, 4, 2?, 2, 1). 



Telson with claws moderately asymmetrical, each precedctl by about 12 very unequal den- 

 ticles, of which 2 or 3 near the middle of the row are nearly as large as the 1st; 1st (anteri- 

 ormost) denticle, and some of those following, armed with very fine spinules. Furca'l claw 

 with 4 plumose setae on the dorsal, inner margin. Dimensions of shell ; 6.6 x 4.0 mm. 



Female: Shell as in ^ but with umbones even less prominent; about 11 growth lines, 

 the outer ones indistinct and crowded and the inner ones very indistinct. Rostrum acute; 

 supraorbital margin of head sinuous. First antennae with about 14 lubes; 2nd antennae with 

 both rami with 11-12 joints; spines on anterior margin of these joints strongly ctenate. 

 Twenty-two pairs of legs (4 specimens) ; 1st pair with 6th endite extending as far as distal 

 end of fiabellum or beyond; palp of 5th endite extending nearly to end of 6th endite; 5th 

 enilite much less than half as long as 6th; 4th endite without i^alp; notches l>etween endites 

 shallow; 9th and 10th legs ovigerous. Last 14 segments of type armed dorsally (formula, 

 from behind forward; 1, 1, 3, 3, 3, 4, 4, 5, 5, 4?, 3, 3, 1, 1). Telson with claws scarcely 

 at all asymmetrical, preceded by about 17 imequal, mostly armed denticles (as in the S ) oi 

 which 2 or more in the middle of the row are about the size of the first (anteriormost). 

 Furcal claw as in the S . Dimensions of shell : 6.0 x 3.8 mm. Eggs rugose. 



No such careful piece of work has ever Ijeen done on the genus Eocycicus as Barnard 

 (1929) has done for Apus, so that the extent of variation within a natural species is not 

 known; nor is it known which of the structural details of these Conchostraca are reliable 

 specific criteria. When such an investigation is made, it may possibly be found that one or 

 both of the above-described species must be reduced to synonymy with others already known, 

 l)ut ill the present state of our knowledge of the group it is probably better to describe as new 

 any specimens about which there is reasonable doubt. 



The nearest described relative to E. hntchinsoni is probably the wide-ranging E. oricntalis 

 Daday, itself very clo.se to E. boiiincri Daday, which differs most conspicuously from the 

 new species in the shape of the rostrum of the S , and in the presence of a well-marked 

 palp on endite 4 of the leg 1 of the ?. E. deterrana is most similar to E. perrieri Daday, 

 from Tobolsk and Buchara, U. S. S. R., but the latter has only 20 pairs of legs, and the 

 ■'hands" of the 5 5 of the two species differ in shape. 



• Oshorn Zoological Laboratory, 

 Yale University. 



