CRUSTACEA OF ALABAMA. 51 



Fam. 2. — Holopedid/E, [extra liraital.] 



Swimming antenna; simple, elongate cylindrical (in the male prehensile), intestine with two lateral di- 

 lations. 

 Tribe II. — Anomopoda. 



Feet five [or six] pairs, the anterior pair more or less prehensile and destitute of branchiae. 

 Fam. 3. — Daphnid^:. 



Rami of antennae three and four-jointed, five pairs of feet, the last with a curved appendage guarding 

 branchial sac ; antennules of female short, one-jointed. 

 Fam. 4. — Bosminid^e. 



Six pairs of feet, antennules elongated, many-jointed. Genus Bosmina. 

 Fam. 5. — Lyncodaphnid.e. 



Antennules of female elongated, but one-jointed; intestine simple or convolute. 

 Fam. 6. — Lynceid/E. 



■ Antennae with both rami three-jointed, intestine generally convolute, with abdominal but no anterior 

 caeca, antennules not elongate. 



SUB-ORDER II.— GYMNOMERA [destitute of covering. J 



Body without, or nearly destitute of bivalve shell; feet not branchiate, spiny. Anterior thoracic ganglia in one 

 mass. 

 Fam. 7. — Polyphemid.b. 



Abdomen curved, terminating in two long stylets. Genus Polyphemus. 

 Fam. 8. — Leptodorid^;. [Extra limital.] 

 Abdomen straight, ending in short claws. 



Key to Genera. 



Fam. 1. Sidid^e. 



a. Head rounded, not acutely beaked below, one ramus of antennae two-jointed, other three-jointed. 



(page 33) Genus Daphnella. 



b. Head beaked below. 



* One of the rami of the antenna; with an expanded plate at the base, antennules large. 



Genus Latona. 

 ** Neither ramus of antennae with expanded plate. 



t Head high, crested, post-abdomen smooth, ..... Genus Limnosida. 



ff Head not strongly crested, post-abdomen spiny. 



1. Antennules of female small, truncate, two-jointed ramus of antennae with few (five) seta;. 



(page t,t,) Genus Sida. 



2. Antennules of female with a long flagellum, two-jointed ramus of antennae with many [over 



8] setae. ...... (P a ge 33) Genus Pseudosida. 



Fam. 3. — Daphnid.e. (See p. 34). » 



Fam. 5. Lyncodaphnid^e. 



A. Intestine more or less coiled. 



a. Intestine with anterior caeca-like appendanges. 



1. Short, shell without a spine above. .... Genus Streblocercus. 



2. Long, shell extending into a spine at the upper posterior angle. . Genus Ophryoxus. 



b. Intestine without caeca. 



1. Five pairs of feet, shell sub-rotund. . . , Genus Drepanothrix. 



2. Six pairs of feet, shell oblong. .... Genus Acaniholeberis. 



B. Intestine not coiled. 



a. Four pairs of feet, antenna; with ten setae. . . . Genus Lathonura. 



b. Five pairs of feet, antennae with eight or nine setae. ■ . (P a g e 37) Genus Macrothrix. 



c. Six pairs of feet, antennae with eight setae, shell not regularly moulted. 



(page 37) Genus Ilyocryptus. 



