DISCUSSION OF SPECIES AND THEIR DISTRIBUTION. 193 



2. Corselet (leveloped. 



a. Palatine teeth strong ; vomer toothless ; vertebra? normal Saui>a 



b. Palatine teeth villi form. 



* Vomer with teeth; vertebrie normal, the lower foramina small. 



Lateral line single Orycnus 



Lateral line d(iul]le Gkammatoucvnus 



* * Vomer toothless; ahdoiniual verteUne with the lower foramina enlarged and a portion 



between the vertebr:e. proper and the hLeuiapoi)hyses developed in the form of a net- 

 work or trellis Gvmnosakda 



II. Body very elongate, compressed. 



A. Spinous dorsal long; pectorals comparatively low; candal not ki'cled; pyloric ca-ca rather 

 few T11YKSITIN.E 



1. Ventrals well developed. 



a. Finlets present; teeth on palatines; body in greater part naked. 



* Lateral line descending lielow posterior part of the spinous dorsal; body rather elongate; 



dorsal and anal tinlets (5 (Type, Thijrsiles utini, South Africa and Van Dieraen's 

 Land) Thyrsites 



* * Lateral line nearly straight; dorsal finlets 5. anal 4 ; body rather elongate.. Tiiyrsitops 



* * * Lateral line absent; finlets few; skin spiuigerous; abd(->men keeled; body somewhat 



elongate Euvettus 



6. Finlets absent; palatines toothless; scales minute. 



* Dorsal in two portions. Dagger-shaped spine behind vent Nesiarchus 



* * Dorsal continuous. Two lateral lines Epinnula 



2. Ventrals reduced to a single spine. 



a. Finlets present ; teeth on palatines, none on vomer. 



* Dagger-shaped spine behind vent. Body much compressed, incompletely covered with 



delicate scales Nealotis 



* * No dagger-shaped spine. Body slender, fusiform; lateral line descending in strongly 



oblique line Iiclow front of spinous dorsal PkclmethichthY'S 



6. Finlets absent; teeth on palatines and vomer. 



* Ventral spine long, crenulate ; preoperculum spiuigerous Dicrotcs 



B. Body very elongate (height 18 to 20 times in length) ; spinous dorsal very long, with numerous 

 spines, continuous with the second; caudal not keeled; pyloric cicca not numerous Gempy'lin.e 



1. Body scaleless ; no palatine teeth Ge.mpyxus 



Subfamily SCOMBRIN.^. 



Scombrids with fusiform, moderately elongate bodie.s, and short (less thau 12 spines) first 

 dorsal fin, separated by a wide space from the second dorsal. Pectorals high up. Caudal 

 not cariuated. 



Several of the forms in the subfamily occur at times far out at sea, but this is no reason 

 for considering them properly pelagic. Like the common mackerel {^Scomber scombrus), 

 which also is found in schools remote from land, they probably all breed near the coasts, 

 and depend for their food upon tlie shoals of small fishes and crustaceans, which are almnd- 

 ant near the land. Scomber spawns at- considerable depths, but probably never beyond 

 the lOOfathom line. It is probalde that mauy of the Soombrnlcc sink at times far below 

 the surface strata, especially in the winter. These matters are but little understood, how- 

 ever, and it is indeed probable that our knowledge of the bathii; distribution of tlie mem- 

 bers of the mackerel family is no more imperfect than our su])posed knowledge of their 

 geographic range and nugrations. The remarks of Valenciennes in the -nistoire Naturclle 

 des lies Canaries" {Poissom,p. 4'J), though written fifty years ago, are worthy of cou.sider- 

 ation to-day. 



Subfamily ORYCNIN^. 



Scombrids having a fusiform, moderately elongate body, and spinous dorsal long, com- 

 posed of more than 12 spines, and contiguous to the second. Pectorals low. Caudal cariiiate. 

 Pyloric cseca very numerous. 



The tunnies, bonitoes, and horse mackerels composing tliis family are even nu)re charac- 

 teristically pelagic than those ot the preceding subraniily, but never have as yet been found 

 below 100 fathoms. There is every reason to siipin)se that at times they sink below the 

 upper strata. 



198GS— No. 2 13 



