262 LOWER VERTEBRATES. 



the islands Jersey and Guernsey, constitute a favorite and highly exciting pastime, 

 indulged in, in summer time, by the members of both sexes and all ranks." 



The common sand-eel of tlie eastern coast of the United States, Ammodytes 

 americanus, has from 125 to 130 lateral oblique folds, and the pectoral fins are much 

 longer than the snout, extending as far back as the front of the dorsal ; it has about 

 28 anal rays. It is very closely related to the common A. tobiamis, or the smaller 

 launce of England. It occasionally, however, reaches a length of about sixteen inches, 

 although it is usually much smaller. On the coast of Xew England it is very com- 

 mon, and it is recorded that on one occasion, in Provincetown harbor, "they covered 

 the ground from one to two inches deep ; and when the water covered the flats, the 

 whole bottom looked like an immense sea of silver." 



So far as superficial evidence goes, all the preceding families appear to belong to 

 one sub-order, although a closer study may reveal diflFerences which should cause its 

 disintegration. But there are still other fishes which cannot be well intercalated in 

 the series, and yet of some very little is known. Two alternatives lie before us in the 

 treatment of such forms: (1) we may either " lump " them with others, because we 

 know not what to do with them, and assume that, if they don't show the characters of 

 the major group into which they are thrust, they ought to, or (2) we may isolate 

 them till we do have more knowledge of them. Of the two evils, the latter course 

 appears to be the least prejudicial to the interests of science. Under special sub- 

 ordinal categories, therefore, several groups of uncertain aflinities may be considered. 

 They are briefly noticed in the order in which they may be supposed to have diverged 

 from the great Acanthopterygian stock. 



Sub-Okder IX. — Hypostomides. 



A family of doubtful relations, formerly placed in the order Lophobranchii, later 

 near the mailed-cheek Acantliopterygians, and by Prof. Cope associated with the 

 Hemibranchii, has been isolated as an independent order (Hypostomides) by A. Dum- 

 eril. It is possible that it may have been an early offshoot from a Percesocine or 

 Acanthopterygian stock, and cognate with the Hemibranchii ; but too little is known 

 of its anatomy to warrant an authoritative opinion. The sub-operculum is wanting. 



Pe6asid.e is the name of the only family of the Hypostomides. The body is wide 

 and covered with jjlates, the snout jirolonged, the mouth inferior, and filamentary ven- 

 trals developed. The few species are confined to the oriental seas. 



Sub-Okdek X. — Rhegnopteei. 



A sub-order named Rhegnopteri has been proposed liy Prof. Cope for a family of 

 fishes of doubtful relations. This family has been generally placed among the 

 Acanthopterygii, but by Prof. Jordan it is classed with the Percesoces. The ventral 

 fins are sub-abdominal, the pelvic bones being disconnected from the scapular arch. 

 One spine and five rays are the complement of each ventral ; the pectorals are 

 inserted in a peculiar way ; the first and the second aetinosts bear the main portion ; 

 the third is transverse and without any rays, and the fourth carries the free anterior 

 or inferior rays. In other respects, the organization is apparently strikingly like that 

 of the so-called acanthopterygians, and it is only the doubt of its proper place that for 



