COMMON SKATK. 



121 



(Dasi/lmtus ex Blaixv.), Bolnml. Fisk:, Gbgs Welt., Wilt. 

 Samh. N. Uandl., part. Ill (1819), p. 21 oiim 2 tnl)b.; 

 Fah. (IfMJa), Fisdi. M.. p. 3,3: Nli,ss., Proilr. Ichthyol. 

 St-aiuL, p. 12{>: YAiiii., Brit. F/.s-A., eii. I, v(,l. 11, p. 421; 

 Fit.. Vet. .\kiifl. Il:aull. 1838, p. 158; MOi.i,., Hlk, Plai/iost., 

 p. 14l-i; Ki!., /i.,,u„. /•'/><•.. vi.l. Ill, p. 978; Nll.ss., 

 .sA-./«./. /''//.,. FiA.. p. 739; Mai.m, Ofvers. Vet. Akad. 

 F.irh. I8.''>7, p. 193; (hHK, Cat. Brit. Mns., Fish., vol. VKI, 

 p. 463; Ltkn, Vid. Meddel. Naturli. For. Kbhvn 1873, 

 p. 3G; Cui.L.. Foih. ViJ. Selsk. Clunia 1874, Tilliegsli., 

 p. 216; 1879. Ni.. 1, p. 106; N. Mag. Naturv. Clirnia, 

 Bd 29, p. 119; Malm {Laciraja ex Salv. ot Bonap.), 

 CVi-/.?. Boh. F,i,i. p. 61,5; WiNTH. (Uaja), Naturli. Tidskr. 

 Kblivii, ser. 3, vol. ,\II, p. 60; MoK., Hist. Nat. Poiss. 

 Fr., ton.. 1, p. 409; Mlhi.. Hckk, /'7s,//. Oste., p. 156; 

 Day. Fi.^h. Ot. livit. B-el.. vol. II, p. 336, tab. CLXVI; 

 Lii.Lj.. ^'v., Aoiy. Fna, Fisk., vol. Ill, p. 584. 



R'liti ijfiiimirdi, ROBEUT in Gaim., Vni/. Isl., GroeiiL, /Cool.,' 

 Bois.s., (abb. 2 et 3; UiUi., Hi.ft. Nat. Pois.o. (n. sii. a Buti.), 

 torn. 1, p. 505. 



Batis riih/,tri.-<, CorcH, FiAi. Brit. hi., vol. I. p. 87, tab. 

 XVIII. 



Most of the coiniiion Skatf t;iki'n in Bohusliln 

 measure between 12 and 1.5 dm. in length, but at this 

 size ai'e hardh' mature. On the south and west coasts 

 of NorwaA" Kkoykk met with specimens 22 — 25 dm. 

 long and rising 200 Norwegian jiounds (100 kilo.) in 

 weight. 



The form of the body is rhoinl)ic, with the anterior 

 side-margins somewdiat undulate and more or less in- 

 curved, the posterior, on the other hand, verv faintlv 

 rounded (convex), with a slight incurvature just behind 

 tlie tip of each pectoral tin. The distance from the tip 

 of tlie snout to the hindmost part of the posterior 

 margin of the pectoral tins is about 74 — 84 % (as a 

 ride about 77 "o), and to the posterior margin of the 

 ventral tins aiioiit 80 — 1)4 %, of the greatest Ijreadth of 

 . the disk. The greatest thickness (the depth at the 

 shoulder-girdle) is about 7 or 8 % of the greatest breadth. 



The form and leugtli of the head vary consider- 

 ablv, in projiortion to the greater or less prolongation 

 of the snout as mentioned above. The longitudinal 

 diameter of the eves is aliout ' ^ — '',; of the length of 

 the snout. The maxinuim diameter of the spiracles is 

 about "5 — ■* .- of that (jf the eves. The internasal width 

 measures about 57 (in young specimens, according to 

 KiiOYER, sometimes 55) — 68 % of the distance between 

 each nostril and the ti|) of the snout, which distance 

 is about 88 (in \()Uiig specimens, according to Kkoyer, 

 sometimes 91) — 88 % of the length of the snout. The 

 breadth of the mouth is about equal in young speci- 

 mens to the internasal width, in older ones perceptibly 



greater, at least 112 — 114 % thereof. The jaw-teeth 

 are comparatively small (fig. 822). On a neck-like, 

 but low base is extended an almost nail-headed disk, 

 the postei'ior pai't of which rises in a- somewhat conical, 

 retrai tip, .short in the females (tig. 828), longer in the 

 males. Teeth of this form are distributed in fairly 

 regular rows, denser in young indi\iduals than in old, 

 both along and across the jaws. The largest teeth, with 

 the longest cusps, are set in the middle of the mouth. 



Fig. 322. Half of a jaw in a male (A) and a female (B) of the 

 pommoii Skate {Raja liatis). Natural size. After LCtkkn. 



the smallest, with hardly a sign of cusp, innermo.st at its 

 corners. As a rule the longitudinal rows number some 

 40 — 50, the transycrse (i — 10. The various ages ex- 

 hibit less difference in the number of the rows than 

 in the form of the teeth, for in very small Skate there 

 is scarcely an indication of the projecting ciisjis which 

 are so prominent in older specimens, especially in the 



Fig. 323. A (ootli of Baja liati.'', $, magnified. 



males; and the whole tooth thus acipiires in the young 

 a plane, lozeng(;-shaped ajjpearance. 



The s])iny armature of the body consists in very 

 young specimens merely of a restricted number of ordi- 

 nary aculei, namely two before and one behind each 

 eye and a row along the u])per median line of the tail 

 with one or two spines between the two dorsal fins. 

 (*f spinuhe there is not a sign in tiiese joung S])eci- 

 mens, either on the dorsal side or the ventral, the 

 body being smooth on both sides. In middle-aged in- 



