The ventral fins are placed below, and slightly farther back than, 

 the pectoral fins. They consist of one strong spine and 5 rays. 



The dorsal fin is double. The first consists of ca 15 spines and be- 

 gins immediately behind the head. (Very unfortunately it is not com- 

 plete on any of the available specimens). The 2nd dorsal fin probably 

 begins just behind the last spine and consits of 18 soft rays. 



The anal fin is placed far back since it begins approximately below 

 the 5th ray of the soft dorsal fin (under the 11th vertebra from the end). 

 It consists of more than 15 soft rays. 



General remarks. A more accurate identification of the above re- 

 mains is hardly possible owing to their poor state of preservation. 

 Their assignment to the Cottidae seems reasonably justified on the 

 following characteristics: lack of spine in the anal fin, presence of 

 two dorsal fins (the number of spines being smaller than that of the 

 soft rays in the dorsal and the anal fins), also the lack of scales, large 

 size of head, narrow body and number of vertebrae. The Cottidae, 

 which have only a few fossil representatives, are known as early as 

 from the Eocene (Woodward 1901). 



PALEOBIOLOGICAL CHARACTERISTICS OF 

 FAUNA FROM THE JASLO SHALES 



Three distinct quantitative groups are readily distinguished among 

 the ichthyofauna from the Jaslo shales: 



(1) forms with luminous organs from the Sternoptychidae and 

 Myctophidae; they occur in great abundance and constitute 76.8 per- 

 cent of the collected material; 



(2) the less numerous specimens of the Gonostomidae and Clupe- 

 idae which constitute 19.8 percent of our material; 



(3) the Cottidae, represented by very few specimens; together 

 with some detached specimens of the genera Equula Cuv. and Sarda 

 Cuv., they constitute 3.4 percent of the whole material. 



Group 1 obviously yields the most substantial information concern- 

 ing the paleobiological character of our fauna. The living forms of 

 both the Myctophidae and Sternoptychidae are bathypelagic fishes. The 

 recent representatives of the Myctophidae occur at a depth of 150 m 

 (Taning, 1918), fide Bertin, Arambourg, 1958) those of the Sternopty- 

 chidae live at between 300 and 600 m (Jespersen, Taning, 1926; fide 

 Bertin, Arambourg 1958); at night-time, they keep near the surface 

 of the water. According to Brauer (1906), living representatives of the 

 Sternoptychidae may be encountered at far greater depths than the 



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