THE AMERICAN NATURALIST. [Vol. XXXVII. 



Tada of Osaka for the Imperial University, the other by Japanese 

 officers for the imperial school of fisheries; 186 species in all were 

 examined. Seventeen new species are described and figured. With 

 them are two new genera, — Zacco (Cyprinidae), based on Opsariichthys 

 platypus and Evenchelys (Mu ran id as), based on Gymnothorax 



tially similar to that of the region about Hongkong, and that it bears 

 much closer relation to that of India than to that of southern Japan, 

 while the fish fauna to the north of Tokyo contains very little in com- 

 mon with that of Formosa. 



One of the new species deserves additional comment. The sys- 

 tematic position of the family of sand launces, or Ammodytidae, has 

 been long in question. Early writers placed it among the jugular 

 fishes as an ally of the cusks and pearlfishes. It has no ventral fins 

 at all, but as there are no spines in any of the fins, it was presumed 

 that the ventrals, if present, would be few rayed and jugular in 



More recently the resemblance in general structure of the sand 

 launces to the silversides and other groups called Percesoces, transi- 

 tional forms between soft-rayed and the more recent spiny-rayed 

 fishes, have led to a reconsideration of this opinion. The Percesoces 

 have abdominal ventrals and the spines little developed. Two argu- 

 ments in favor of this view have seemed to have value. In 1811 

 Pallas described an Ammodytes septipinnis from the Aleutian Islands. 

 This species, not since recognized, is said to be an Ammodytes, or 

 sand launce, with the ventral fins eight-rayed and abdominal. For 

 this species Dr. Gill has suggested the generic name of Rhynchias. 



In the Oligocene rocks of Puy-de-D6me Dr. Gervais has discovered 

 a fossil fish, now called Cobitopsis acuta, which resembles a sand 

 launce in most respects, and is referred to the Ammodytidae by 

 Boulenger. In this species the ventrals are six rayed, and abdomi- 

 nal. The dorsal fin, unlike that of Ammodytes, is rather shorter than 

 the anal and opposite to it. There are no fin spines. The long dorsal, 

 without fin spines, the numerous vertebras and abdominal ventrals with 

 six or eight rays, appear also in the extinct family of Crossognathidae 

 of the Cretaceous. This family is certainly allied to the Percesoces. 

 This evidence seemed conclusive, and the sequence" of families, 

 Crossognathidae, Cobitopsidae, Ammodytidae, and Atherinidae, seemed 



The tropical Ammodytidae, having normal scales and fewer verte- 

 brae, have been referred to the genus Bleekeria. In the collection 



