34 
PACIFIC SCIENCE, Vol. XXI, January 1967 
races. Brady’s living specimens of L. alata off 
Honolulu are much smaller (length 0.44 mm) 
than those dealt with here, and his figures do 
not show the slight median compression. Adult 
Recent specimens from T-13, however, are com- 
parable to Brady’s form except that they are the 
same size as the fossil form, i.e., 0.52 mm long. 
The Recent form has more winglike alae with 
a more posteriorly pointing trend. Sexual 
dimorphism with thinner males (?), as noted 
by Brady, does not occur in the present speci- 
mens. Both fossil and Recent forms possess a 
slight enlargement in the posterodorsum re- 
sembling Loxocorniculum (Benson and Cole- 
man, 1963); however, this enlargement does 
not always occur in the fossils. 
Some confusion exists between the type 
species of Loxoconcha alata Brady, lS6Sb, 
from the Mediterranean, and forms similar to 
the present species. The original description of 
L. alata shows an elongate, finely and concen- 
trically pitted carapace with pointed alae. In 
dorsal view it is more anteriorly acuminate. 
Keij’s identification of L. alata (Keij, 1953: 
160) is probably based on Brady’s (1880) mis- 
identification, as was Fyan’s (1916), even 
though Brady (1886) expressed doubts about 
his earlier identification when he stated that 
the specimens comprising the species L. alata 
Brady, 1880 "are, I think, identical to” L. 
gibbera from Ceylon.. They probably are not, 
and there appear to be several species of alate 
loxoconchids from the Mediterranean, Indian, 
and Pacific regions. Other papers reporting, but 
not describing, "L. alata Brady,” are by Brady 
(1886, 1890), Chapman (1902), Scott 
(1905), and Bold (1946£). 
Genus Loxoconchella Triebel, 1954 
Loxoconchella honoluliensis (Brady), 1880 
Figs. 24 a-c 
Loxoconcha honoluliensis Brady, 1880. Rept. 
Voyage Challenger, Zool. 1, pt. 3, p. 118, pi. 
28, figs. 6 a-f. 
Loxoconchella honoluliensis (G. S. Brady) 
Triebel, 1954. Senckenbergiana 35, p. 19, pi. 1, 
figs. 1-6. 
diagnosis : Evenly inflated punctate carapace ; 
prominent posteroventral keel; and lenticular 
shape in dorsal view. 
description: In lateral view: greatest cara- 
pace height in posterior half; dorsal margin 
straight between high eye tubercle and concave 
posterodorsum ; anterior margin evenly and 
broadly rounded; ventral margin straight in 
anterior half; caudal process distinct, at mid- 
height; surface finely punctate (not illustrated). 
In dorsal view: carapace lenticular; greatest 
width at midlength; posterior compressed; left 
valve overlapping right valve in posterior third. 
Hinge adont: bar of left valve a continuation 
of anterior margin along dorsum to postero- 
dorsal cardinal angle, with well-developed cen- 
trodorsal accommodation groove; posterior ele- 
ment a distinct groove from posterodorsal 
cardinal angle to base of caudal process. Other 
internal features not preserved. 
dimensions: 
PLESIOTYPE 
LENGTH 
HEIGHT 
WIDTH 
usnm 648780 
(entire $ ) T-4 
0.67 
0.47 
0.34 
SDNH 1055 
(entire $ ) T-13 
0.52 
0.36 
0.25 
SDNH 1056 
(right valve $ ) T-4 
0.65 
0.46 
0.17 
DISTRIBUTION: As 
fossils 
from 
T-l (2 
valves), T-4 (1 valve; 1 entire), and T-7 (6 
valves ; 2 entire) ; found living in the Hawaiian 
Islands at T-13 (1 valve; 1 entire) and Easter 
Island at EA-1 (2 valves). Reported living by 
Brady (1880) off reefs at Honolulu at 40 
fathoms, and by Brady (1890) at New Cale- 
donia at 2-6 fathoms, and at Fiji and Samoa 
in the littoral zone. 
discussion: Variation in the development of 
reticulations occurs in the present specimens, 
with a few individuals from T-7 being orna- 
mented somewhat like Loxoconchella anomala. 
However, the reticulations on L. honoluliensis 
are never as deep as on L. anomala. 
Following Brady (1880:117), the com- 
pressed form is considered to be the male. This 
expression of sexual dimorphism is uncommon 
in the family Loxoconchinae, where the males 
are usually longer than the females. 
Loxoconchella anomala (Brady), 1880 
Figs. 25 a—f 
Loxoconcha anomala Brady, 1880. Rept. Voy- 
age Challenger, Zool. 1, pt. 3, p. 123, pi. 28, 
figs. 5 a-d. 
