cruish. In niaiiiier cil' lite tliey essentially resemble the 

 preeediui!; Kmas; hut iii;m\- of thein (leseeiul to greater 

 depths. Tliey are oviparous; l)ut the embryo leaves 

 the egg very soon after the exclusion of the latter 



s. 110 1 



from the eluaea, or even durinjr its transmission through 

 the said passage. 



Of the four or five genera which the family con- 

 tains, the Scandinavian fauna possesses only one. 



Gems RAJA". 



• The pectoral fins do not extend in front of the rostral cartilaqe. Tin' ventral fins are deeply forked at the hind 

 margin. Where a caudal fin is present, it does not extend to tin' under surface of the tip of the tail. 



The foundation of our knowledge of the species 

 belonging to this genus and tlieir mutual relations, 

 especially as they appear in the Scandinavian fauna, 

 was laid in its essential details by B. Fiuics''. His tirst 

 remarks had reference to the value of the specitit' char- 

 acters emploved at his time within the genus. 



The spin\- 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 minutiaj, such as counting the 

 number of the spines, determining their positions iind 

 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 tind without fail that the 

 armature, however similar it may appear at tirst 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, 

 hut also in such normal deviations from the original 

 specific type as age and, in part, the difference of sex 

 entail. I'or the attainment of descriptive lucidity Fries 

 proposed the following terminology. Smdtaf/gar (spi- 

 iiiihc) he called the prickles that cause the asjx-rity of 

 the skin. The\- are (juite small and short, either subu- 

 late, with a bifid or (juadrifid, stellate base (spinulce 

 stellares), or granular {granuloses). Knaggor {aculei) 

 was the name he aiJjilied to the large, claw-shaped, 

 and usuallv recurved, thorn-like spines which stand as 



column, on the rostral cartilage, around the orbital 

 margin, and on the dorsal side above the scajmlar re- 

 gion, parth' at other undefined spots and in highly 

 variable number i)()tli on the dorsal side and the ventral 

 {acidei extraordinarii). Both these kinds of aculei vary 

 in number, form, and size, are shed pei'iodically 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 spinukv 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, parti}- and principally on the pectoral tins, 

 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 



wound-inflicting weapons partly at certain flxed spots on ] former type, on the other hand, is often overlooked 

 thebody(fff«/e«ord»(ff ;•/«)> namely in rows along the spinal | and mistaken owing to the considerable modifications 



" Artedi, Ichthijol., Gen. Pise, p. 70. "'Est 

 ' See Vet. Akad. Handl. 1838, p. 12G. 



L-abuhnii I'MNII. Dcrivatio .liibia" (ART., Phil., p. 7.H). 



