FISHES OF FAMILY MICRODESMIDAE — REID 57 



reasonable to assume that this species represents the maximum in 

 variation of the fin-ray counts of the known species. In this series of 

 30 specimens the fin-ray counts are as follows, the figure in parentheses 

 representing the number of specimens: 



Dorsal fin: 73 (3), 74 (4), 75 (6), 76 (4), 77 (9), 78 (4). Anal fin: 

 58 (9), 59 (10), 60 (5), 61 (5). Counts of body myomeres: 19 (2), 

 20 (19), 21 (9). Counts of caudal myomeres: 38 (1), 39 (5), 40 (15), 

 41 (8), 42 (1). 



The myomeric impressions are counted from the base of the pectoral 

 fin, along flank to above vent, and to the hypural. Vertebrae counts 

 are from X-ray photographs. 



It was found impracticable to separate the counts of the vertical 

 fin supports into spinous and soft ray sections, the difference between 

 the anterior and posterior portions being so gradual that no definite 

 point of differentiation can be reliably fixed. 



I am indebted to Dr. George S. Myers, formerly assistant curator 

 of fishes. United States National Museum, for valuable assistance in 

 the preparation of the manuscript and key. The vertebral counts 

 were made possible by courtesy of the authorities of the United States 

 Naval Hospital and of Dr. Dirk Meindert te Groen, Lieutenant 

 (M. C), U. S. Navy, in charge of X-ray. 



Genus MICRODESMUS Giinther 



Microdesmus Gunther, Proc. Zool. Soc. London, 1864, p. 26. (Type, Micro- 



desmus dipus Gunther.) 

 Cerdale Jordan and Gilbert, BuU. U. S. Fish Comm., vol. 1, p. 332, 1881 (1882). 



(Type, Cerdale ionihas Jordan and Gilbert.) 

 Leptocerdale Weymouth, Proc. U. S. Nat. Mus., vol. 38, p. 142, 1910. (Type, 



Leptocerdale longipinnis Weymouth.) 



Body moderate or very elongate, slender, somewhat compressed. 

 Vertebrae moderate or numerous. Head short, snout obtuse, usually 

 with swollen longitudinal ridges or muscular folds. Mouth smaU, not 

 protractile, more or less obUque. Lips thick, with pronounced flanges. 

 Chin strongly projecting in the anterior profile, usuafly with longi- 

 tudmal ridges. Vertical fins long and low, united with the caudal by 

 membrane. Gill openings restricted laterally, oblique, broadly 

 joined to the isthmus. Ventral fins closely approximated, rays 1-3. 

 Teeth in the jaws in two irregular series, absent on vomer and pala- 

 tines. No cirri or filaments. Lateral line absent. 



SmaU anguilliform fishes of tropical shores and tidepools, Hving in 

 burrows in sand or mud. 



