6o REPORT OF XEW JERSEY STATE MUSEUM. 



April 5th, 19 1 2. It was very abundant, frequently occurring 

 with other small entomostracans. I next found, it in May of 

 19 1 2 in a small tributary of the Delaware below Florence, where 

 it was quite abundant with species of Scapholeberis, and in July 

 and August it was abundant about Trenton. It likely occurs 

 throughout the State. 



Chydorus bicornutus Doolittle. 



Plate 8. 



Chydonis bicornutus Doolittle, Proc. Biol. Soc. Wash., XXII, 1909, p. 154. 

 Sebago Lake, Songo River, Panther Pond, Maine; Umbagog Lake, New 

 ' Hampshire. 



Doolittle, Proc. U. S. Nat. Mus., XLI, 191 1, p. 165, Pis. 17-19. (Maine 



and New Hampshire.) Grover Mill Pond, Princeton, New Jersey. 



Fenmle.—Eody rounded in lateral vie\\ , ventral margin sharply 

 ventricose. Body as seen from above broadly oval, front same, 

 and sides concave dorsally. From each valve body a great 

 horizontal horn stands out, curving slightly posteriorly, often 

 half width of body proper. From this horn two high ridges run 

 forward, and also two over back from horn to horn. An area on 

 back immediately anterior to interspinal ridges bounded laterally 

 by two other ridges. Near front limiit of area, these ridges, 

 after giving off on each side high lateral branch, sharply con- 

 verge and unite in median line, forming a short crest where head 

 and body meet, then diverging on head they bound or enclose 

 large area in front and continue down tO' tip of rostrum. On 

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

 origin near each other at upper end of ascending anterior mar- 

 gin of valve, and running more or less parallel to margin, but 

 second and fourth from margin not running whole length o^f 

 valve. First and third, however, unite at dorso-posterior angle, 

 run forward on back to interspinal ridges, flaring outward, thus 

 united ridges of opposite sides bound a dorsal area posterior to 

 interspinal ridges. Between parallel ridges, except those arising 

 fromi lateral horns, there pass partitions forming deep large 

 rectangular cells. Within areas as described similar cells of 

 various sizes and shapes. Laterally above marginal ridges other 



