38 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 122 



on slide no. 1900-3-6-457 (British Museum) but not on mandibles 

 on slide no. 1900-3-6-458 (British Museum). 



Maxilla (fig. 16f/) : 2nd joint of endopodite with 2 slender bristles 

 on outer side, 1 short bristle on inner side, and 5 stout terminal 

 bristles with marginal spines. 



The maxilla was the only appendage illustrated by Brady and 

 Norman (1896, pi. 9: fig. 18). It is essentially the same as the maxilla 

 on slide no. 1900-3-6-458 (British Museum) illustrated in this paper 

 (fig. 16^). 



Seventh limb (fig. IQe): 6 bristles in terminal group; 2 bristles in 

 proximal group; all bristles with 2-4 distal bells. 



The distal tip of the 7 th appendage can not be observed clearly 

 on British Museum slides (1900-3-6-457; 1900-3-6-458). This limb 

 was not described by Brady and Norman (1896). 



Furca (fig. 16/): each lamella with 5 curved claws decreasing in 

 length posteriorly; claw no. 1 joined to lamella; claws 1-3 with lateral 

 and medial spines in row along concave margin. 



Brady and Norman (1896, p. 678) described the furca as having 6 

 claws. In both British Museum slides (1900-3-6-457; 1900-3-6-458) 

 the fm-ca is compressed, making the claws difficult to distinguish ; 

 however, only 5 claws can be observed on each lamella. 



Sarsiella disparalis Darby 



Figures 17-19; Plate 4 

 Sarsiella disparalis Darby, 1965, p. 40, pis. 30, 31. 



Holotype: Museum of Paleontology, University of Michigan, 48819, 

 female. 



Darby (1965, p. 40) described S. disparalis based on 5 females 

 collected off Sapelo Island, Ga. The shells of his specimens varied 

 considerably in ornamentation, some weakly and others strongly 

 ornamented, or the right valve ornamented and the left valve almost 

 plain. I received 2 mature females of this unusual species, both with 

 asymmetrical shells, in a collection from the Atlantic shelf off Beaufort, 

 N.C. To determine whether the asjniimetrj^ and variability of the 

 shells might be caused by parasitism, both specimens were examined 

 for parasites, but none were found. Left and right appendages were 

 compared to determine if asymmetry in valves was reflected in them, 

 but differences were found to be minor. Examination of a slide 

 (UMMP 48818, no. 86) of a paratype prepared by Darby revealed 

 the presence of a parasitic copepod of the family Choniostomatidae, 

 but it is not considered likely that it is the cause of shell asymmetry 

 in S. disyaralis because the specimen containing the copepod is fairly 

 symmetrical. Both the holotype and the above-mentioned paratype 

 were examined. 



