LARVAL AND POST-LARVAL FISHES—REGAN. 127 
the head, so that the migration of the anus backwards during the development of 
this species is established. 
Moreover, it is evident that Prymnothonus is not a valid genus, but merely a 
larval form of Notolepis, Paralepis, ete. 
The capture of this example in the Ross Sea completes the evidence that Notolepis 
coatsii is circumpolar, for it had previously been taken near Peter Island, at the 
South Orkneys and in the Weddell Sea, and near Wilkes Land. 
Myctophum, sp. 
Some specimens, very much damaged, taken on March 27th, 1912, at Station 
238; 52° 11'S., 167° 25’ E., 30 metres. 
The largest, 13 mm. long, is very similar to the somewhat larger example of 
M. punctatum, Rafin. figured by Holt and Byrne (Fisheries Ireland Sci. Invest., 1910, 
VI, pl. I, fig. 1), but differs in that the anal papilla is separated by an interspace from 
the anal fin. I count 40 myotomes and 20 anal rays; the dorsal fin appears to have 
been bitten off. 
Myctophum antarcticum, Ginth. (PI. I, figs. 1-3). 
A number of examples of this circumpolar species, 10 to 18 mm. in length, were 
taken in the Subantarctic Zone at Stations— 
235 52° 41'8., 168° 15’ E., 10 metres, March 26th, 1912. 
238) 9) B22 WS: 167° 25) Ey 30°, — March 27th; 192: 
ZA0. = 5 1-57’ S., 167° 88’ BH, 4 «, © March 28th, 1912. 
250,251 54° 2'8.,177° 0’ W., surface, Dec. 20th; 1912. 
Doo. HAS 38) S., 176° 55! Wi, Dec. 21st, 1912. 
808 . 55°29'S., 78°54' W., 4 metres, April 9th, 1913. 
In adult examples, 60 to 100 mm. in length, I count 13 to 15 dorsal and 18 to 
22 anal rays, and 40 to 42 myotomes. I find the same numbers in the larger 
specimens (14 to 18 mm.) of the “Terra Nova” collection, which have the fin-rays 
developed, but differ from the adult fish in the following points :— 
(1) There are no scales or photophores, except a single photophore on each side 
above the base of the pelvic fin. 
(2) The dorsal and anal fins are lower, the caudal fin is less emarginate, the 
adipose fin is longer, and the paired fins are shorter. 
(3) The fish is more elongate, and the snout is proportionately longer, the eye 
smaller and the maxillary shorter, not reaching the vertical from the 
posterior edge of the eye. 
(4) There is a prominent anal papilla, and from it a membranous fringe runs 
forward to the base of the pelvie fins. 
(5) There is a small sinus, subdivided by septa, persistent above the occipital 
it 9 
