RAYS. 
1101 
guish. In manner of life they essentially resemble the 
preceding Rays; but many of them descend to greater 
depths. They are oviparous; but the embryo leaves 
the egg very soon after the exclusion of the latter 
from the cloaca, or even during its transmission through 
the said passage. 
Of the four or five genera which the family con- 
tains, the Scandinavian fauna possesses only one. 
Genus RAJA'k 
The pectoral fins do not extend in front of the rostral cartilage. The ventral fins are deeply forked at, the hind 
margin. Where a caudal fin is present , it does not extend to the under surface of the tip of the tail. 
The foundation of our knowledge of the species 
belonging to this genus and their mutual relations, 
especially as they appear in the Scandinavian fauna, 
was laid in its essential details by B. Fries 6 . His first 
remarks had reference to the value of the specific char- 
acters employed at his time within the genus. 
The spiny armature of the body, he wrote, has 
been the chief specific distinction employed since the 
infancy of science, and it also affords beyond all question 
not only clear, but also really trustworthy characters, 
if only we refrain from minutiae, such as counting the 
number of the spines, determining their positions and 
size, as has hitherto been customary, for it is in this 
very manner that most of the nominal species and the 
constant confusion of the species arise. Every one who 
studies the species by comparing a number of indivi- 
duals, and who afterwards compares nearly related spe- 
cies with each other, will find without fail that the 
armature, however similar it may appear at first sight, 
yet follows in each species a distinct development, char- 
acteristic of the species, and expressed not only in the 
form, size, position, growth, and shedding of the spines, 
but also in such normal deviations from the original 
specific type as age and, in part, the difference of sex 
entail. For the attainment of descriptive lucidity Fries 
proposed the following terminology. Smdtaggar ( spi - 
nulce ) he called the prickles that cause the asperity of 
the skin. They are quite small and short, either subu- 
late, with a bifid or quadrifid, stellate base ( spinulce 
stellares), or granular ( granuloses ). Knaggor ( aculei ) 
was the name he applied to the large, claw-shaped, 
and usually recurved, thorn-like spines which stand as 
wound-inflicting weapons partly at certain fixed spots on 
the body (aculei or dinar ii), namely in rows along the spinal 
column, on the rostral cartilage, around the orbital 
margin, and on the dorsal side above the scapular re- 
gion, partly at other undefined spots and in highly 
variable number both on the dorsal side and the ventral 
(aculei extra or dinar ii). Both these kinds of aculei vary 
in number, form, and size, are shed periodically or 
accidentally broken off, in which case, however, they 
always leave, at least for a time, a mark in the skin. 
Furthermore both may occur with expanded, flattened 
or nail-headed base (aculei clavati), or with expanded, 
conical base, deeply grooved on the sides and as it 
were radiate (aculei radiati). Besides spinulse and aculei 
the Rays have a third kind of spines, but only the 
males. These Fries called the cards of the males (car- 
mines maris). They are situated on the dorsal side of 
each half of the body, partly at the outer margin of 
the head, partly and principally on the pectoral fins, 
a little way from the tips thereof. They consist of 
rather long, simply bent or hooked, and very pungent 
spines, set in rather irregular longitudinal rows, and 
furnished with a mobile attachment, so that the Ray 
can depress or erect them at will. When depressed, 
they lie close to the skin, and may easily escape ob- 
servation. By the distribution of the aculei on the tail 
Fries distinguished between two types among our in- 
digenous species, the one with an odd number of lon- 
gitudinal rows, the other with an even number. The 
latter type — as exemplified in the Shagreen Skate and 
the Sandy Ray — seems hardly ever to be impaired by 
exceptions or to alter with the age of the individual, 
but is always recognisable by the symmetrical rows of 
aculei (arranged on each side of the median line). The 
former type, on the other hand, is often overlooked 
and mistaken owing to the considerable modifications 
“ Artedi, Ichthyol., Gen. Pise., p. 70. 
b See Vet. Akad. Handl. 1838, p. 126. 
“Est vocabulum Plinii. 
Derivatio dubia” (Art., Phil., p. 73). 
