North American Fresh-icater Ostracoda. 423 



Shell strong, irregularly tuberculate or spinous, rather 

 thin and horny in texture; extremities yellowish or 

 hyaline. 



The first pair of antennge five-segmented, provided 

 with short bristles on their outer edge ; second pair four- 

 segmented, the "spinning claw" being either two-seg- 

 mented or unsegmented. The branchial plate of the 

 mandible strongly developed (commonly rudimentary in 

 other genera of this group). Caudal rami rudimentary, 

 commonly but two short bristles. 



Males are rare. Previous to Yavra's monograph 

 (68) but five species were known: L. sancti-patricii 

 B. & R.; Z. monstrifica Norman, from England; Z. 

 inopinata Baird, from England and Sweden; Z. relkta 

 Lillj., from Sweden; and Z. incisa Dahl, from Germany. 

 Yavra (68) adds Z. stations as new, and Zschokke (76) 

 has recently described L. neocomemis from Switzerland. 

 I have found two species which presumably are not yet 

 described. 



Limnicy there reticulata n. sp. (PI. XXXIX., Fig. 1-7.) 

 A small form, .66 to .73 mm. in length, .35 ram. 

 high, and .25 mm. broad; grayish white. Shell sparsely 

 hairy at the anterior and posterior ends; conspic 

 uously marked with a honeycomb-like network of polyg- 

 onal reticulations (Fig. 1 and 2), which are somewhat 

 similar to those of Z. smicti-jpatricii and L. ilUnoisensis, 

 but with lateral furrows which serve at once to distin- 

 guish it from these species. The upper anterior part, in 

 the neighborhood of the eye, is nearly free from reticula- 

 tions, marking the position of a lateral depression which 

 is deepest near the middle of the shell, becoming shal- 

 lower anteriorly. 



Seen from the side (Fig. 2), the shell is evenly and 

 gradually rounded at both ends; dorsal margin straight, 

 the ventral sinuate, the deepest part slightly anterior to 

 the middle; posterior part somewhat broader than the 

 anterior. 



