2 Pisces. 
PISCES. 
I B. Monorrhina : 1. Operculata ; 2. Inoperculata! II. Entomocrania. — 
I 1 . Operculata ; 2. Inoperculata. 
( The stages of subordinate differentiation are as follows : — 
I Apodal or pedate. When pedate, the limb skeleton constructed npon 
I the type of the archipterygium, the ichthyopterygium, or the chirop- 
j terygium. When the limb is an ichthyopterygium, it is either unibasal, 
j tribasal^ or multibasal. 
i The Chondrocranium is constructed upon either the ‘ amphistylic,’ the 
i ‘ hyostylic,’ or the ‘ autostylic ’ plan. 
I In a tabular view, the stages of general differentiation are indicated 
i on a vertical line from which horizontal lines are drawn ; those of 
I subordinate differentiation of the skull and limbs, on a horizontal line 
l^from which vertical lines are drawn, P. Z. S. 1870, pp. 24-58. 
Geographical Distribution. 
! The distribution of the families of Fishes, with the range of such 
( genera as inhabit fresh-water, is discussed by A. R. Wallace in “ The 
' Geographical Distribution of Animals” (London : 1876, 2 vols. 8vo), 
v vol. ii. chap. 20, pp. 424-467. 
Faunae. 
Arctic. 
C. Liitken, in “ Korte Bidrag til Nordisk Ichthyographi,” gives a 
preliminary revision of the northern species of Cottidce. This is pre- 
faced by important remarks on the growing need of some complete 
critical and descriptive work on Arctic Ichthyology, no longer to be met 
! by a re-edition of Otto Fabricius’ book on the fauna of Greenland. 
His ultimate hope is to produce such a work ; and, in the mean- 
i time, he will publish his results on the different families, in an 
I abridged form, to meet the present requirements of more precise data 
I concerning such northern types and representatives. Vid. Medd. 1876, 
\ pp. 355-388. 
Eurojpe. 
R. Siey’ers, in Bidrag till kannedom om Hogland's lisk-fauna,*' 
Medd. Soc. Fenn. i. pp. 60-64, enumerates 19 species from that Finnish 
locality, with local names. See also 0. M. Reuter, tom. cit. p. 129. 
Collett, R. Norges Fiske, med Bemaerkninger om deres Udbredelse. 
. Christiania : 1875, 8vo, 240 pp. 2 pis., map. 
The first enumeration ever made of the fishes of Norway, with notes on 
their geographical distribution. In a systematic table at the end of the list, 
pp. 225-236, the author separates four different ichthyological districts 
of Norway. The new discoveries are Cottunculm mkrops, g. & sp. nn., 
Coitus lilljeborgi^ which has been found recently by Liitken at the Faroe ' 
Islands; Motella, septentrionalis [Zool. .Rec. 1875, p. 122], Lycodes 
esmarki (possibly founded npon very old specimens of L. vahli, 
