ANGLEK. 



141 



the interoperculal spine) is divided iiiln Ihrcc l)i-;in(hes, 

 tlic lii'st ;i(l\;incini;' along' llie I'heek, the st-ennd ;d<ing' 

 the lower jaw, and the (liird in a posterioi' dii'celion 

 on the hranchiostegal uicnibrane, to thr lower iiiariiiii 

 ol' tlie base of the pectoral fins. 



Thanks to tlie investigations of A. Aoassiz", we 

 now ha\c coniiih'te information of tlie great changes 

 which the form of the Angler undergoes during growth. 

 Off Newport and in Massachusetts l>ay (N. America), 

 during the month of August, Agassiz found band- 

 shaped, gelatinous masses floating at the surface, 2 or 



end)r\<) is still enclosed in the membrane of the egg 

 (tig. ;')('), (I and //), the pectoral fins have begun to ap- 

 pear, in the form of dermal flaps on the sides, behind 

 the head; and on the back, vertically above them, a 

 pi'otuberance rises towards the dorsal edge. From this 

 protuberance the first ray — which subsequently 

 becomes the second — of the dorsal fin soon rises; and 

 simultaneously, as soon as the embryo has left the egg 

 and befoi-e the yolk-sac is entirely absorbed (fig. 36, c), 

 there apj)ea.rs on each side of th(' belly, l)elow the base 

 of the pectiM'al fill, a caulifoi-m (jr somewhat clavate 



3 feet broad and from 25 to 30 feet long, of a light ! process, which is the rudiment of the first (outermost) 



violet-gray colour, but covered with black dots arranged ' soft ray in the ventral fin. This process, which for a 



in one layer. The dots are the eggs, in which the ' time (fig. 37, r/) is geniculate, grows longer and longer, 



black-coloured embryos are still enclosed (fig. 36, a). , On its inner side (fig. 37, c) there appears the rudi- 



Fig. as. Young of Loplihis piscatoriiis. a: vviUi 4 rays in the dorsal fin and with the rudiments of the caudal fln ( + ): I': with 6 rays in 

 the first dorsal fin, with heterocercal caudal fin, and with the second dorsal and the anal tins almost typical in form; c; the same specimen, 



seen from above and less powerfully magnified. After Al. Agassiz. 



In their first stages these embryos, or even the hatched ment of a new (inner) ray, and this new formation on 



fry, are scarcely recognisable as belonging to this spe- ■ the inner side is repeated once more during the growth 



cies. The body is elongated, and the head luj broader of the rays. \Mien the longest of them (tig. 38. h 



than in the ordinary fish-embryo. The embryonic tin- | and v) is considerably longer than the whole body of 



membranes of the dorsal and ventral edges — on the the fish, the membrane of the ventral fins is also highly 



hitter the membrane extends only behind the vent — developed, and the rudiment of the outermost (first) 



are united at the end of the tail (diphycercal); and ' ray in tliese hiis (the spinous ray) begins to appear. 



the comparati\'eh- thick notochord is almost jieriecth" 

 straight all the way to this point. But even wliiK- the 



Meanwhile the rays of the first dorsal tin (fig. 37, (I, 

 (' and /' and tiu'. 38, a, b) also increase in the same 



" I'roc. Anicr. Acad.. 1. c. Cf. also B.Miii.. American Naturalist, vol. V (1871), p. 785. We hare only very little information, with 

 this exception, of the propagation of the Angler: we only know that males are rarer than females, and that Thompson estimated the number 

 of eggs in a gravid female 4'., feet in lengtli to be 1,427,344 (see D.-\Y, 1. c), while B.\iRD calculated that there were at least 432,000 in 

 the gelatinous mass found by him. 



