DEVONIAN FISHES OF IOWA 



253 



Pakeophichthys parvulus, sp. nov. 

 (Text-fig. 37) 



A very small species, attaining a total length of 4 or 5 cm, with 

 very slender, elongated, eel-shaped form of body. Length of 

 head contained nearly six times in the total length. Arrange- 

 ment of cranial plates indistinguishable, and extremity of tail 

 deficient in the solitary known specimen. Paired fins not ob- 

 served. Median fins continuous, the dorsal arising behind the 

 occiput at a distance equal to about one and one-half times the 

 length of the head itself, and the origin of the anal not far 

 behind that of the dorsal. 



The original specimen serving for the holotype of the above 

 defined genus and species is preserved in counterpart, as is 

 usually the case when organic nuclei are exposed within iron- 

 stone nodules at the Mazon Creek locality in Grundy county, Illi- 

 nois. It at one time formed part of the S. S. Strong collection, 

 and is now the property, along with the type of Coelacanthus 

 exiguus from the same locality and horizon, of the Museum of 

 Comparative Zoology at Cambridge, Massachusetts. Interest- 

 ing as the specimen is on account of its relations and general 

 features, it is to be regretted that it is defective as regards 

 preservation of certain parts, the head region being encrusted 

 with a whitish film of silicious matter, the extreme tip of the tail 

 wanting, and no trace remaining of the paired fins. 



The most salient and at the same time truly surprising charac- 

 teristics of the new form are two : first, the anguillif orm propor- 

 tions of body; and secondly, the continuity of the median fins. 



,i0^mm 



Fig. 37. 



Fig. 37 .—Palseophichthys parvulus, sp. nov. Coal Measures; Mazon creek, Illinois. 

 Lateral aspect ol holotype showing elongate form of body, degenerate squamation, and 

 continuous median flns, x 2-1. 



