4 BULLETIN 150, UNITED STATES NATIONAL MUSEUM 



The synonomy given is based mainly upon the material examined. 

 This is the only satisfactory method of dealing with these fishes. 

 It is extremely difficult or impossible to decide upon the specimens 

 listed by others. The synonomy of the American and Asiatic species 

 is easily traced out, but that of the European species is impossible 

 without an examination of the material in the museums of Europe. 



The material upon which this report is based consists of the collec- 

 tions in the American Museum, the Museum of Comparative Zoology, 

 the United States National Museum, United States Bureau of Fish- 

 eries, and the Stanford University Zoological Museum. Altogether 

 about 830 specimens have been examined, and these represent 90 

 species. The collections well represent the family and form a satis- 

 factory basis from which to build a monographic report. 



The drawings of the teeth were made by W. L. Atkinson, under a 

 grant from Stanford University, from camera lucida drawings by 

 the writer. 



A bibliography €onsisting of the most important papers relating 

 to these fishes is appended. 



I wish to acknowledge my indebtedness to Dr. David Starr Jordan, 

 Dr. C. H. Gilbert, Dr. Bashford Dean, and Dr. Samuel Garman, for 

 assistance and advice received during the preparation of this report. 

 Dr. Peter Schmidt of the Imperial Museum of St. Petersburg, and 

 Shigeho Tanaka, of the Imperial University of Tokyo, very kindly 

 sent material for examination Mr. Barton A. Bean, of the United 

 States National Museum, gave the writer every assistance possible in 

 the examination of the collection in his charge. 



PART 1. GENERAL 



The Liparidae or sea snails comprise a group of softbodied degen- 

 erate fishes related to the Cyclopteridae and Cottidae. They agree 

 with the Cyclopteridae and differ from the Cottidae in having the 

 ventral fin modified into a sucking disk. In some of the deep-sea 

 genera the disk has become lost. The Liparidae and Cyclopteridae 

 had a common origin and closely resemble each other. The former 

 can be distinguished from the latter by the more slender, shorter 

 trunk and the more elongate caudal region. 



These fishes are specialized for a bottom existence both in the shallow 

 waters and the deep sea. Only one species is known to belong to the 

 plankton. This species, Nectoliparis pelagicus, is found in mid- 

 ocean between 300 and 600 fathoms. The most familiar species are 

 those found in the tide pools, where they rest under or cling to the 

 rocks. 



Collecting. — The tide-pool species are sluggish and easily captured. 

 The turning over of rocks along the shore frequently exposes species 

 which can readily be seized. Baling out tide pools or sprinkling in 



