Late Cenozoic Ostracodes — Holden 
31 
t 
(6 valves; 5 entire); T-13 (2 valves; 1 entire). 
discussion: Loxoconcha postdorsolata Puri, 
I960 from the Gulf of Mexico and Loxoconcha 
condyla are similar. The latter does not have 
the large posterodorsal tubercle that the former 
has; it does, however, possess a small pointed 
extension of the carapace in the same area. 
Recent representatives of the species occur in 
the Hawaiian Islands at 22 fathoms on Penguin 
Bank and at 5 fathoms in Hanauma Bay. At 
both Recent stations specimens are much smaller 
than the fossils, i.e., only 0.44 mm in length. 
In all other aspects the Recent forms appear 
conspecific with the fossil forms. The descrip- 
tion of the internal features was taken from 
these better preserved specimens. 
The species is named with reference to the 
small, knuckle-like enlargement in the postero- 
dorsum. This feature is variably developed, be- 
ing practically absent in some individuals. 
Loxoconcha sp. 
Figs. 22 a-b 
description: In lateral view: shell sub- 
rhomboidal; length twice the height; dorsum 
straight in anterior half, undulatory in posterior 
half, parallel with straight ventral margin; an- 
terior margin bluntly rounded ; posterior margin 
bluntly pointed in dorsal half; ornamentation 
of faint random pustules. In dorsal view: shell 
conspicuously sulcate toward posterior; anterior 
pointed; posterior blunt. 
Hinge gongylodont: posterior element of 
right valve a socket bracketed by two teeth 
connected above; anterior element a tooth 
bracketed by two sockets ; other internal features 
obscured. 
dimensions: Specimen usnm 648775 (right 
valve) T-12: length, 0.52; width, 0.13; 
height, 0.28. 
distribution: As fossil from T-12 (1 en- 
tire) . 
discussion: Lack of adequate specimens 
prohibits a more detailed description of the 
species. The single right valve is unquestionably 
fossil, as attested by the partial encrustation of 
manganese oxide on its outer surface (Fig. 
22 b). 
To the writer’s knowledge there are no 
known pustulose species in the genus Loxo- 
concha. The pustules on the present species are 
probably a secondary effect caused by corrosion, 
the sieve pores being somehow more resistant 
than the remainder of the valve. 
