Doolittle — New Cladocera from New England. loo 



liorn. An area on the back immediately anterior to the interspinal ridges 

 i8 bounded laterally by two other ridges. Near the anterior limit of the 

 area, these ridges, after giving off on each side a high lateral branch, 

 sharply converge and unite in the median line, forming a short crest where 

 head and body meet ; then diverging on the head they bound or enclose 

 a large area in front, and continue down to the tip of the rostrum. On 

 the lower half of each valve are four more high ridges, taking their origin 

 near each other at the upper end of the ascending anterior margin of the 

 valve, and running more or less parallel to the margin, but the second 

 and fourth from the margin not running the whole length of the valve. 

 The first and third, however, unite at tlie dorso-posterior angle, run for- 

 ward on tlie l)ack to the interspinal ridges, flaring outward ; thus the 

 united ridges of opposite sides bound a dorsal area posterior to the inter- 

 spinal ridges. Between parallel ridges, except those arising from the 

 lateral horns, there pass i^artitions, forming large, deep, rectangular cells; 

 within the areas as described are similar cells of various sizes and shapes; 

 laterally above the marginal ridges are other deep liexagonal cells of var- 

 ious sizes. 



Eye large, with few facets, ocellus adjacent. Rostrum long, acute, 

 covered with ridges and cells similar to those of the valves. Labrum 

 from side view with anterior lobe blunt, i)osterior lobe digitate, and cili- 

 ated distally. Maxillae with two heavily ciliated teeth. Feet, five, very 

 similar to those of C. favi/ormis Birge, which the deep faviform cells 

 cavises it to reseml)le. Postabdomen broad, rounded distally, with twelve 

 spines on dorsal or anal border, daw strong, crumbled, Ijasal teeth two, 

 the proximal smaller. 



Male, unknown. 



Measuremetitii. — Length of body proper about .55 mm., add { to \ for 

 ridges; width, about .45 mm., add ^ to } f'<^>r horns; height aVjout .50 

 mm., add. ^ to ^ for ridges. 



