1 ANNUAL SUMMARY OF SCIENTIFIC AND 



type of marine turtles referred to the family Sjyhargididce, 

 but distinguished by remarkable characters. Another inter- 

 esting form is Agathaumas sylvestris, a genus of the order 

 Dinosauria, and supposed by its discoverer, Cope, to deter- 

 mine the cretaceous age of the Wyoming formation, in which 

 it was found. Researches on the Pythonomorpha, certain gi- 

 gantic fossil serpents (see p. 256, 258), and the discovery of 

 the remains of pterodactyls by Marsh and Cope in the cre- 

 taceous formation of Kansas, deserve to be signalized (see p. 

 244, 338). 



The Fishes have been the subjects of study from an ana- 

 tomical stand-point, and with a view to the improvement of 

 their classification by Cope, Dareste, and Gill, although at 

 first sight appearing to differ radically from each other, the 

 differences of their several systems are not really as great as 

 they seem to be. The anatomy of some interesting forms 

 has been examined by Gunther and Gegenbaur, the former 

 having made known the structure and relations of Ceratodus 

 in a very full monograph, and the latter having illustrated 

 the craniology of the sharks. A valuable memoir has been 

 published by Putnam on the Hypsmidw, a family of which the 

 blind fish of the Mammoth Cave is the type. Several inter- 

 esting fossil forms found in the cretaceous and tertiary forma- 

 tions of the United States have been described by Cope (see 

 p. 258, 368), and some interesting carboniferous types in En- 

 gland by Hancock and Attley. 



The announcement made by Professor Agassiz in regard 

 to the habit of the Chironectes (a pelagic fish) of building an 

 artificial nest of sea-weed, in which the eggs are intertwined 

 and allowed to float in the open ocean, has also attracted 

 much attention. 



Gill has reopened the question of the homologies of the 

 scapular arch, agreeing with Gegenbaur and Parker in respect 

 to the constituents of the scapular series as a whole, but in- 

 terpreting entirely otherwise the several elements of which 

 it is composed. 



The much-vexed question as to the mode of generation of 

 eels has been elucidated by the publication of a work by an 

 Italian author, who takes the ground that the animal is real- 

 ly a hermaphrodite, and that during the winter season both 

 sets of sexual organs are brought to their functional activ- 



