io CRUSTACEA OF ALABAMA. 



the species. Should it prove that this like other Calanidse is dimorphous T. clausii 

 may disappear and the old name T. velox will then be restored for both forms. 



Claus is certainly in error in calling the fifth pair of feet 4-jointed, as shown by his 

 own figures and especially those of Poppe. Great interest attaches to this find, because 

 it seems to indicate that the same morphological species has arisen under similar condi- 

 tions in isolated stations. Should the species be found along the Atlantic coast, how- 

 ever, this assumption will be unnecessary. 



The curious resemblance, amounting almost to identity, betwen the Temora armata 

 of Claus, and Brady's T. dubia, is likewise instructive, leaving very little doubt of close 

 genetic relationship. 



Boeck's description of T. biennis is here translated for the sake of completeness. 

 (See Oversight over de ved Norges Kyster iagttagne Copepoder ; Vidensk.-Selskab. 

 Forhandlinger, 1864, p. 16.) 



Length about 1.50 mm, transparent, colorless, with yellow viscera and a yellow band on 

 the posterior part of the head and another upon the first segment of the abdomen. The 

 body greatly elongated, slender. Head divided by a transverse suture into two parts, 

 likewise the fourth and fifth segments distinctly separated. The fifth segment in the male 

 rounded, in the female accuminated. The first joint of the abdomen in the male, but the 

 middle one of the female the shortest. The caudal appendages elongate, but shorter 

 upon the abdomen of the male. The outer seta attached nearer the middle than the end 

 of the caudal stylets. The anterior antenna of the male is strongly swollen in the mid- 

 dle and is armed with small spines upon the eighth to the twelfth joints. Last foot of the 

 female two-jointed, first segment short ; second longer, oval, provided on the outer angle 

 with a spine, on the inner, with a longer curved spine-like process, at the apex is a long, 

 straight spine. The fifth legs of the male are three-jointed ; second joint of left limb 

 shortest, the third expanded at the end ; first joint of the right foot long, but less broad ; 

 spines on the inner angle very small ; third segment rather longer and provided at the 

 end with simple teeth. 



The Temorella (Eurytemora) hirundo of Giesbrecht differs from T. affinis only in 

 three very significant particulars, first, the body is more slender, second, the caudal sty- 

 lets are considerably longer, third, the last segment of the thorax is rounded instead of 

 acute, and bears minute bristles. The close agreement of the other parts suggests a lo- 

 cal race or variety, but it may be best to retain the name notwithstanding. 



Genus Pseudo-diaptomus. (Herrick.) 



Resembling Metrida and Diaptomus ; compactly framed ; cephalothorax 6-jointed, 

 last two segments coalescent above; head rounded in front, beaked; eye small; anten- 

 nae appearing 22-jointed in both sexes, longer than the thorax; the right male antennae 

 genicuiate as in Diaptomus ; antennules bi-ramose, both rami rather short, inner one 

 seeming but two- or three-jointed ; mandible ten-toothed ; maxillipedes well developed ; 

 feet all bi-ramose save the last, both rami 3-joited ; first feet smaller ; fifth feet with inner 

 ramus obsolescent, in the male nearly as in Diaptomus, in the female rather slender, 



