Bd. V: 6 ) THE FISHES OF THE SWEDISH SOUTH POLAR EXPEDITION. 21 
therefore might sometimes appear as an atavistic feature, and for that reason such a 
characteristic cannot suffice to distinguish two species or subspecies of Ilucocoetes , 
but taken together with others it is of importance. And it is in this case not only- 
different colouration but differences with regard to the relative dimensions as well, 
by which the present specimen is to be distinguished trom Ilucocoetes fimbriatus , as 
it is described in the literature, and from a specimen obtained by this expedition at 
Tierra del Fuego, stat. 60 as well. The description of the present specimen is as 
follows. 
Length of head fully 5 times in total length. Depth of body about three fourths 
of the length of head and more than 7 times in total length. Snout longer than 
the diameter of the eye (about 8 /s of the latter). Eye and interorbital space about 
equal, contained about 5 3 /s times in length of head. The maxillary seems to ex- 
tend to below the middle of the eye. A rather broad cutaneous flap at the corner 
of the mouth, two more between the same and the nasal tube, and a median 
one between both nasal tubes. Below the lower jaw three cutaneous appendages 
alternate with large mucous pores on either side. Both upper and lower lips are 
“fleshy” and folded. The dorsal begins in front of the extremity of the opercle. 
Pectoral contained about i 3 / 4 times in length of head. Distance from base of pec- 
toral to vent about 1V3 as long as head. Ventrals short, contained about 7 times 
in head or 4 times in pectoral. 
From this is apparent that this form differs from the typical I. fimbriatus through 
its longer snout and smaller eye, shorter ventrals and especially by the much greater 
distance between base of pectoral and vent. The typical 7 . fimbriatus is also said 
to be of a uniform colouration. 
Steindachner has used the same name for a fish from eastern Tierra del 
Fuego collected by Plate,* but the relative dimensions etc. of that fish differ so 
much from the corresponding ones recorded for I. fimbriatus that it seems rather 
uncertain whether the identification is correct. On the other hand it must be ad- 
mitted that Steindachner’s specimen is rather large, measuring about 252 mm. 
and it is not known in this genus, how the relative dimensions are altered during 
the growth. Steindachner’s specimen has a much smaller head and eye and this 
may be due to greater age. 
The differences between this transversely banded Ilucocoetes and the specimen 
from Tierra del Fuego collected by this same expedition cannot be explained as 
depending upon different age as both are young and nearly of the same size. The 
following table of comparative measurements may therefore prove the existence of 
more than one form of Ilucocoetes. 
Die Fische der Sammlung Plate, Fauna Chilensis, Hft 2 Zool. Jahrb. Suppl. 1S98. 
