322 
PACIFIC SCIENCE, VoL IX, July, 1955 
Argyropelecus heathi, Fowler, 1928: 35 (Alika, 
District of Kau, Hawaii). 
Argyropelecus hemigymnus , Schultz, 1938: 146, 
148 (listed from Hawaiian Islands). Ha- 
waiian records not A. hemigymnus Cocco. 
Argyropelecus heathi, Fowler, 1938: 265 (listed 
only). 
material examined: 3 specimens, 20.3 to 
27.6 mm. in standard length, taken off the 
Mauna Loa lava flow, Hawaii, by Y. Yama- 
guchi, June 6, 1950. 
1 specimen, 30.3 mm. in standard length, 
taken off the Mauna Loa lava flow, Hawaii, 
by Gosline, Hayes, Keen, and Ellis, June 
6, 1950. 
The only previously known specimen of 
this species in addition to the holotype was 
recorded by Fowler (1928). This specimen, 
which was killed by the Mauna Loa lava flow 
of 1919, was presented by the collector to the 
Bernice P. Bishop Museum and thus was not 
among the fishes reported by Jordan (1921) 
from that lava flow collection. 
Although not reported in the literature from 
any area outside of the Hawaiian Islands, the 
species is also known from the eastern Pacific 
on the basis of records as yet unpublished. 
The reasons for retaining Argyropelecus 
heathi as a separate species from A. hemigymnus 
Cocco will be discussed in a forthcoming 
paper by Dr. Rolf L. Bolin and the present 
writer. 
Argyropelecus sladeni Regan 
Argyropelecus sladeni Regan, 1908: 218 (type 
locality, Salomon, Chagos Archipelago, In- 
dian Ocean, 400-500 fms.). 
MATERIAL examined: 1 specimen, 64.4 mm. 
in standard length, taken off the Mauna Loa 
lava flow, Hawaii, by Hayes and Burke, June 
2, 1950. 
3 fragmented specimens, taken off the 
Mauna Loa lava flow, Hawaii, by Moore et 
al., June 3, 1950. 
10 specimens, 47.4 to 75.9 mm. in standard 
length, plus 1 fragmented specimen, taken 
off the Mauna Loa lava flow, Hawaii, by Y. 
Yamaguchi, June 6, 1950. 
Opinion differs among various authors as 
to the status of several closely related Argy- 
ropelecus species, of which A. sladeni is one 
(Norman, 1930: 301, 304, text fig. 13; Parr, 
1937: 46, 50, text figs. 18, 19; Schultz, 1938: 
147, 153). Until collections from all parts of 
the world are compared, this problem cannot 
be resolved. However, the Hawaiian spec- 
imens are of the relatively slender-bodied type 
with long upper preopercular spine and low 
dorsal blade, and fall within the limits of A. 
sladeni as interpreted by all three of the authors 
cited above. It seems best to assign them to 
this species for the present. 
A. sladeni , as presently defined, is known 
from the Atlantic, Antarctic, Indian, and east 
and west Pacific oceans. It has not previously 
been reported from the Hawaiian Islands or 
anvwhere in the central Pacific area. 
RELATIONSHIPS 
Aside from those pertaining to the Ha- 
waiian Islands, there are no published records 
of hatchetfishes from the central Pacific re- 
gion. Nevertheless it is probable that future 
collecting will add several more species to the 
five now known from this area. In view of the 
fact that most sternoptychids are very widely 
distributed, occurring in several of the great 
oceans, it would be difficult to make a general 
statement as to the relationships of the central 
Pacific sternoptychid fauna or to predict 
which species would be most likely to be 
found there in the future. 
REFERENCES 
Bohlke, J. 1953. A catalogue of the type 
specimens of recent fishes in the Natural 
History Museum of Stanford University. 
Stanford Ichthyol. Bui. 5: 1-168. 
Fowler, H. W. 1928. The fishes of Oceania. 
Bernice P. Bishop Mus., Mem. 10: (iii) 1-540, 
pis. 1-49. 
