456 



SC'AN])INAVIAN FISHES. 



Genus ZEUGOPTERUS. 



Jair-teeth of uniform size (no canines), j)ointed, recurved, small, and set in a card on the front part of the inter- 

 maxillary hones and of the lower jaw. Head of the vomer also furnished with small teeth, hut the pcdatine hones 

 and tongue smooth. Lower pharyngeal teeth set in several rows {cardlform). Most of the fn-rays hranched. Bran- 

 chiostegal memhranes partiaUy united helow, hut furtlier hack meeting in different planes, the one crossing the otlier. 

 Branchiostegal rays 7 . Median wall of the hranchial cavity pierced ahove the urohyoid hone hy a hole. Ventral 

 fins united hy the fn-memhrane to the first ray of the anal fin. Scales on the eye side of the hody ciliated at the 

 hind margin, on the hlind side smooth-margined- Anal spine and preanal spines wanting. Distance hetween the 



anal fin and the tip of the snout less than the length of the head. 



Only one species of this <ienus is known, the sy- 

 stematic significance of which in relation to tlie \)ve- 

 ceding genera we have already touched upon. The 

 characters on which the genus is Ijased, nre, however, 

 of only secondar)- rank. In a young specimen, 12' ., 

 mm. long, whicli the writer took in n hoop-net at the 

 surface, at about tlie middle of the west entrance of 

 the English Channel, where there were 55 fathoms of 

 water, and in which specimen the right eye had only 

 just begun its passage under the free, projecting front 

 part of the dorsal fin, the ventral fins are separated 

 from the anal fin l)y an interval equal in length to 



their own bases, and both tlie dorsal and the anal fins 

 terminate [josteriorly at the middle of the edges of the 

 body. The independence of the genus has tluis no more 

 significance than thnt of a distinct stage — the most 

 advanced of all — in the course of development that 

 has started from an ancestral Bothoid type common to 

 this genus and the preceding one. 



The genus was established in 1835 by Gottsche, 

 but gained no further recognition until Steensthup, who 

 included in it the two preceding genera as well, thirty 

 years after pointed out the characteristic breach in the 

 wall between the two branchitd cavities. 



MULLER'S TOPKNOT (sw. ludna hvarfyen" or nnRGHVARrvEN''). 

 ZEUGOPTERUS PUNCTATUS. 



Plate XIX, fig. 2, and fig. Ili5. 



Greatest depth of tlie hody more than 46 %, total length of the head more than 26 %, length of the head hehind 

 the lower eye more than 14 %, maxillary hones of hoth sides more than 10 %, hranches of the lower jaw more 

 than 12 %, pectoral fin nf the hlind side more than S %, hase of the dorsal fin (measured in a straight line) more 

 than 84 %, its greatest depth (longest ray — ahout the 60th — 70th) more than 11 %, hase of the anal fin more than 

 73 %, its greatest height {longest ray — about the 40th — 47th) more than 11 %, distance hetween the anal fin and the 

 tip of the snout less than 23 %, length of the middle rays of the caudcd fin less than 13 %, greatest thickness of 

 the hody more tha)i 7 % — in each case relatively to the length of the hody. Length of the pectoral fin of the 

 hlind side less than 77 %, hut more than 66 %, of that of tlie lower jan- on the same side, and the length of the 

 middle caudal rays less than either the length of the lon-er jaw or half the length of tlie head. 

 Least dex)th of the tail less than 16 ?6 of the greatest depth of the body. 



R. hr. 7; D. 87 — 99'^; A. 61— li''; P. sin. 11 1. 12, dextr. 

 10 1. 11 (12); V. 6; V. 2 + 12 + 2''; Liu. lat. ca 200; Vert. 3G 1. .37. 



/Hi/n. Pleuronectes piiacUttus, Bl., Natury. Ausl. Fische, part. Ill, 

 p. 31, tab. CLXXXIX; Walb., Ichth. Art.. i)art. Ill, p. 



116; Gthr {Rhombm), Cat. Brit. Mas., Fish., \v\. IV, p. 

 413; Coll. (Zeugopieriis), Forli. Vid. Selsk. Christ. 1874, 

 Tilla?gsh., p. 139; Mai.m, Gbgs, Boh. Fn., p. 518: Winth., 

 Natiirh. Tidskr. Kbhvn, ser. 3, vol. XII, p. 38; Day, Fish. 

 Ot. Brit., Irel.. vol. II, p. 18. tab. C; Coll., N. Mag. 



" NiLSSON, 1. C. 



* Malm, 1. c. 



■■ Soraetinics 101, according to Day. 



** Sometimes 80 or even 89, according to Gottsche. 



' Or 1 + 14 + 1, or 2 + 13 + 1. 



