170 GEOL. AND NAT. HIST. SURVEY OF MINNESOTA. 



* Ceriotlaphnia alabaiuensis Herrick. 



Plate XLII, Fig. 2. 



(American Naturalist, May, 1883. Piate V, Figs. 11, 12.) 



This species was seen but once and is insulficiently known. The 

 body is elongate, quadrate, the shell reticulated with double contour 

 lines, the head very small and produced downward below the eye, 

 which is very small, the antennules are longer than in any other spe- 

 cies, obviously two-jointed, with a lateral seta; the antennae are very 

 long; post-abdomen long and rather narrow, with the margins nearly 

 parallel, truncate at the end, with over nine anal spines; claws 

 smooth, abruptly truncate. My drawing represents a daphnia-like 

 set of processes for closing the brood cavity. Length 1.0 mm. 



Tuscaloosa, Ala. 



* Ceriodaplinia reticulata Jurine. 



Plates XLI, Figs. 15, 21; XLII, Fig. 3; XLIII, Fig. 3; XLIV, Figs. 3, 4. 



Monoculus reticulatus — Jurine. 

 Daphnia reticulata — Baird, Leydig. 

 Ceriodaphnia quadrangula — Schoedler. 

 Ceriodaplinia fischeri — Leydig, Schoedler, etc. 



Head long, obscurely angled in front of the antennules; fornices 

 very prominent; antennules small; j)Ost-abdomen of moderate size, 

 rounded at the end, slightly tapering; about eight long anal teeth; 

 terminal claws with a series of sharp spines at the base. The reticu- 

 lations are sharp but simple. The flagellum of the male antennule is 

 either straight or moderately curved. Kurz says that some varieties 

 have the fornices blunt while others are sharp. I have seen only the 

 blunt form, which is then much like the next. 



[* Cerioclaphnia dentata Birge.] 



This form differs from the above only in having the inside of the 

 claws fringed with minute bristles (sometimes absent), the angle of 

 the head being more marked and the fornices less prominent. It is 

 difficult to say whether our Minnesota specimens most resemble this 

 or the typical G. reticulata of Europe. They seem intermediate, some 

 having fornices with an abrupt angle. It may be instructive to quote 

 Kurz on the European G. reticulata: "Examples occur 0.8 to 0.9 mm. 

 long, others on the contrary only 0.5 to 0.6 mm. long and combining 

 with the smaller size some differential characters. In the larger va- 

 riety I found the fornix obtuse, while in the smaller it extends in a 

 sharp thorn directed upward and outward. In this small sub-species 



