-Notidamidans. 
Galeods. FISHES. 
165 
caudal being likewise undeveloped. The scales have 
three keels, and as many points. The only genus, 
Ti’iaJds, has been detected in the seas of Japan only. 
Family VII.— MUSTELIDANS (Mustelidce). 
In the position of the fins and stigmata, and the 
presence of nictitating membranes and spout-holes, 
this family corresponds with the Galeidans and the 
Scylliodonts. The spout-holes are large, the orbits 
longish, and the nictitating membrane swells out like 
a doubling of the under eyelid. A three-sided lappet 
with a rounded tip embraces three-fourtbs of the nostril 
above, and there is a shorter blunt lappet on the outside 
of the orifice. The first dorsal stands nearly midway 
between the pectorals and ventrals, and the caudal fin 
is short. The teeth are like those of a skate, being 
flat without cusp or sharp edge, and arranged like a 
mosaic pavement. There is but one genus, which is 
represented in our seas by the Smooth Hound {Mustelus 
vulgaris). 
Family VIII. — LAMNAEDANS {Lamncedm). 
These are Sharks which have, like the three imme- 
diately preceding families, two dorsals and one anal, 
and the first dorsal placed over the space between the 
pectorals and ventrals, but they have spout-holes, and 
want the nictitating membrane; the stigmata are 
long, and are all before the pectorals ; the orbits are 
roundish ; the caudal fin is crescentic, the upper lobe 
being but slightly longer than the under one, and the 
anal and second dorsal, which are opposed to one 
another, are both small ; the tail is keeled on each side, 
and the spout-holes are very small. 
The dentition varies in the different genera, which are — 
Lamna; Oxyrhina; Carcharodon; imA.Selache; in some of whom 
the teeth are the most formidable that occur among the existing 
Sharks. 
In the British seas the Lamna cornuhica is not 
uncommon. It is known, according to age, as the 
Porbeagle or Beaumaris Shark. A white Shark of 
formidable size is also recognized by fishermen as being 
occasionally met with, but its proper genus has not yet 
been ascertained. In the posthumous edition of Yar- 
rell’s “British Fishes” it is conjectured to be the Carcha- 
rodon requiem. The Basking Shark {Selache maxima) 
sometimes strays from its native haunts in the north 
sea to the coasts of Scotland and Ireland. It is a 
sluggish, and not a dangerous Shark, though one of 
the largest of its order, and attaining a length of thirty- 
six feet and upwards. 
Family IX. — ODONTASPIDANS (Odontaspida). 
lateral caudal keel, like that of the Lamnadans. The 
front teeth are very large, and resemble curved three- 
sided spike nails. The single genus Odontaspis con- 
tains only one or two species. 
Family X. — ALOPECIANS {Alopecicedai). 
As in the two immediately preceding families, the 
spout-holes of this group are so small as to be often 
overlooked ; nictitating membranes are wanting, and 
the first dorsal is before the ventrals, but the very great 
length of the upper lobe of the caudal furnishes a dis- 
tinctive character. The snout is short and conical ; 
the small nostril is protected above by a short marginal 
lappet ; there are no labial cartilages ; and the stig- 
mata are short as in the Carcharidans, the last one 
being over the base of the pectorals. The teeth, which 
are alike in both jaws, are lancet-shaped and trilateral. 
A single species of the oidy genus is known in our seas 
by the names of Fox-shark or Thresher {Alopecias 
vulpes), in allusion to the size of the tail, which the fish 
employs in its combats with the Cetaceans as a thresher 
would use a flail. 
Family XI. — CESTEACIONTS {Cesiraciontidce) . 
This family consists of a single genus of only two 
species, one of them Australian, where it is commonly 
known by the name of the Nurse {Cesiracion phillipi ) ; 
another inhabiting the seas of China receives the local 
name of Kitten Shark {Cestracion zebra). This genus 
connects existing Selachians with palteozoic fishes. The 
Cestracionts have the cleft of the nostril prolonged to the 
margin of the mouth, which is at the front of the snout, 
and wants the superior corner-fold. The spout-holes 
are distinctly visible behind the eye, and the stigmata 
are small, with the last one over the base of the pec- 
torals. A strong spine stands in front of each dorsal, 
and the short caudal fin has a notch on the under edge 
of its superior lobe. The flat pavement-like teeth form 
oblique rolls, like the spires of some univalves. 
Family XII.— EHINODONTS {Rhinodontidai). 
This family is represented by a single known species 
{Rhinodon typicus)., which frequents the seas round the 
Cape of Good Hope. It is characterized by a flat 
head with the mouth and nostrils at its end, a triangu- 
lar nasal flap, very small spout-holes and stigmata, 
diminishing in size as they recede from the head, the 
last one being situated over the base of the pectoral. 
The caudal is crescentic, without a notch in its upper 
lobe ; and the very small and numerous teeth are coni- 
cal and card-like. 
Agreeing with the Carcharidans and the six families 
immediately following that group in the relative posi- 
tion of the fins, and with the Lamnaedans in having 
spout-holes but wanting nictitating membranes, the 
Odcataspidans are further characterized by their large 
stigmata situated wholly before the pectorals, large 
second dorsal and anal, and the upper lobe of the 
caudal elongated as in the Carcharidans ; they have no 
Family XIII.— NOTIDANIDANS {Notidanidce). 
This family differs from all the preceding Selachians 
in having only one dorsal, and from all the order in 
having more stigmata than five on each side. The 
Notidanidans have an anal fin and have been called 
“ Galeidans which want the first dorsal.” The spout- 
holes are small and vertical, and there are no nictitating 
