AI{(iYHOriCI,KCU.s (ILKKRSII. 



929 



tlicir surface show any regular streaks or the like." 

 Of the lateral line v. Duben and Kouex saw only a 

 trafc, "in tlic turni of an elevated line hcyiiuiinL;' l)e- 

 i(i\v tiie origin of the true dorsal tin, iind ruiuiing 

 alonU' the nuddle of the body tt) tiie base of the 

 caudal fin." 



The luminous spots are distributed as follows. 

 On the under side of tiie lower jaw — on tlie soft 

 chin" — below the tij) of the lingual bone, lie two ra- 

 ther undefined spots, wiiieh ai'e probabh' luminous'', 

 thonuii ill this si)eeies, to the best of our knowledge, 

 the\ have not \ci l)een examined. On the eeratohyoid 

 bones, in the skin between the bases of the Hrst (low- 

 est) 7 branehiostegal rays, there are ti small luminous 

 spots on each side of the body. l>eliind these each 

 side of the isthmus is furnished with 6 larger luminous 

 spots, gradually increasing in size as the isthmus grows 

 deeper behind. These are succeeded, on each side of 

 the sharp prealidominal margin of the belly, by a row 

 containing 12 luminous spots of fairly uniform size, 

 somewhat smaller than those on the isthmus and small- 

 est at the beginning and end of the row. .\bove the 

 rows on the isthmus and the preabdominal margin each 

 side of tiie liody bears a row of 10 luminous spots; 

 hut this row is interrupted and belongs partly to the 

 head, parth' to the abdominal region. One spot lies 

 within the anterior (horizontal) arm of the preoper- 

 ciiluia, but spreads downwards over the anterior part 

 of the interopereulum. Another, smaller spot occupies 

 the lower part of the suboperculuin and the hind part 

 of the interopereulum. Two large spots adjoin to the 

 hind margin of the clavicle above the insertion of the 

 pectoral fin, and are indeed vertical in direction, but 

 set so tliat their tops form a continuation of the curve 

 followed \i\ the upjier jiarts of the spots on the isth- 

 mus. Tile remaining six alidominal spots are about 

 ei|ual in breadth to the last-mentioned pair but shorter 

 than they, and lie in a continuous, horizontal row, but 

 lower than the last-mentioned pair. Each of them 

 occupies the space between two ribs, and lies vertically 

 or oblicpielv above one of the spots in the lower jire- 

 abdominal row, the penultimate spot, however, being 

 situated above t!ie penultimate two in the lower row, 

 both of wliicli oc(up\" the same intercostal s])ace. The 

 segmental arrangement of the luminous sjjots is thus 



not obser\'ed \\itli complete luiiforinity. Each side of 

 the jiostabdoniinal mai'gin liears a continuous row of 

 1 luminous spots. Owing to the singular form of tiic 

 body these spots are indeed set at the ventral margin, 

 i. e. tiieir lower pai'ts extend thither, but also on a 

 level with the two large spots above the insertion of 

 the in'ctoral tin. In size thej' answer most nearl\' to 

 the spots in I lie u]i|ier preabdominal row, which the\ 

 also resemble in tiic eirenmstance that the s])ots on 

 one side of the l>od\' do not coalesce internalh' (supe- 

 riorh ) with those on the other side, as is the case 

 witli the lower preabdominal row. The postabdominal 

 spots on one side of the body are aLso .separated in- 

 feriorly from tiiose on the other: their defining walls 

 do not coalesce below, like those of tiie preabdominal 

 spots, into a median edge. ( )n each side of the bod^■ 

 the walls coalesce into a more or less high, thin rim, 

 and together form in this manner a groove or deej) 

 channel, open below, at the hind extremity of which the 

 vent is situated. The luminous spots on the tail form 

 two groups, the one, along the posterior two-thirds of 

 the base of the anal tin, l)eing a row of 6 rather large 

 spots, the 2nd, 3rd, and 4th smaller than the rest, the 

 other a row of 4 smaller spots at the inferior margin 

 of the tail, just in front of the caudal fin. All these 

 luminous spots thus belong to the lower part of the 

 body. Higher up we find, however, an isolated lumi- 

 nous s]iot on each side of the head, on a level with 

 the tip of the snout. This spot is situated on the 

 uppermost part of the preoperculum, just below its 

 articulation. 



The above description of the luminous spots in 

 Arfjj/ropelecKS Olfcrsii applies in every detail to the 

 analogous organs in Argyropdecus liemigi/mniis, a ]\Ie- 

 diterranean and Central Atlantic form which in other 

 respects too so closely resembles A. Olfersii that it 

 evidently represents a lower stage in the same course 

 of development. 



Arfiiiropehcus Olfersii has been named after a 

 Prussian diplomatist who, while on a voyage to Brazil, 

 secured an example of this species that had become 

 entangled among weeds to a lead-line, "between the 

 Canary Islands and l^>razil." The specimen figured liy 

 CrviEU (1. c.) was found by DussiiMiek some kilom. 

 south-east of the Cape of (iood Hope, among a floating 



" Meiititiii, pars inter gnaUiidia mollis (SiJNunvALL). 



' Cf. Arffi/ropelectis lienn'i/i/miuis and Sterixrpti/x diaphaixi, LEXiiENFELti in Gi'.N-iUKR, Deep Sea Fish., 1. c, p. 314. 



