280 PROCEEDINGS OP THE AMERICAN ACADEMY 



the surface ; the pectorals were similarly covered. The general tint 

 of body and fin was gray, with blackish and yellowish pigment cells. 



LOPHIUS PISCATORIUS, Lin. 



(Plate XVI. figs. 2-5 ; Plates XVII., XVIH.) 



The eggs of Lophius are laid embedded in an immense ribbon- 

 shaped mucous band, from two to three feet broad and from twenty- 

 five to thirty feet long. This geiatinous mass is often found floating 

 on the surface of the sea during the last part of August. It looks at 

 a short distance like an immense crape. The mucous mass is of a 

 light violet gray color, and the dark black pigment spots of the young 

 Lophius, still in the egg, give to the mass a somewhat blackish ap- 

 pearance. The eggs are laid in a single irregular layer through the 

 mass, usually well separated by the mucus in which they float (Plate 

 XVI. fig. 2). 



When just hatched (Plate XVI. fig. 4) it would be difficult to 

 recognize the young as the embryo of Lophius. It has but a . single 

 first dorsal element, a narrow short spathula-shaped ventral, and a small 

 circular pectoral. These characters, with its transversally flattened 

 body and head, seem in this stage to have no relation to the vertically 

 flattened adult Lophius. The embryo in this stage, as well as while 

 still in the egg (Plate XVI. fig. 3), and until it is far more advanced 

 (Plate XVI. fig. 5, Plate XVII. fig. 7), is remarkable for the great 

 width of the embryonic fin fold along the dorsal and ventral lines, 

 the very straight notochord, and the three or four prominent patches of 

 intense black pigment cells placed at equal distances along the lower, 

 upper, and terminal parts of the chord. The tail pigment spots extend 

 on both sides of the notochord, and form the largest of the three patches. 

 This is the case from the earliest stages, until the body of the young 

 Lophius is completely covered by pigment cells, as in the oldest stage 

 here figured (Plate XVIII. fig. 2). I have already on a former occa- 

 sion figured some of the changes which the tail undergoes as the 

 embryo passes from the stage of Plate XVII. fig. 3, to the oldest 

 stage of the young Lophius (Plate XVIII. fig. 2). 



The principal changes of form of the body of the young Lophius 

 consist in the gradual flattening of the head, and at the same time the 

 increase in the proportion of the head as compared to the rest of 

 the body, — a feature in which Lophius and the Cottoids differ some- 

 what from the post-embryonic changes of other osseous Fishes, where 



