ICHTHYOLOGICAL COLLECTIONS OF THE ALBATROSS. 463 
In a young specimen, 145 mm. long, taken from the egg, having the yolk nearly 
absorbed, no spines are externally visible. They are fully developed, however, 
and lie declined and hidden beneath the epidermis. The three ocular spines, the 
postoccipital spine, and the caudal series are all present. No rudiments of spines 
are visible in the mid-dorsal region, between the postoccipital spine and the middle 
of the ventrals. On freeing them from the epidermis the spines can be readily 
elevated and depressed. The posterior attachment of the base is, however, firm, and 
will not permit the elevation of the spine beyond a certain point. Later, a firm 
anterior attachment is formed, the spine in the meantime breaking through the skin. 
When it first appears it is still movable, but soon becomes rigid. 
In still younger embryos, 120 and 125 mm. in length, the spines are represented by 
elongate soft, dermal papillw, of about the same size and shape as the future spines. 
They occupy the same definite positions found characteristic for the spines of this 
and related species. The papill lie declined beneath the epidermis, through which 
they are visible as short whitelines. Norudiments appear between the postoccipital 
papilla and the base of the ventrals. 
A specimen 190 mm. long has the spines fully developed and the mid-dorsal series 
nearly complete. Thus the caudal series continues forward beyond base of ventrals 
for about three spines, and is then followed after a short interval by three stronger 
spines, the anterior of which is the postoccipital spine, as indicated by its charac- 
teristic position. In another specimen, 200 mm. long, a continuous dorsal series is 
present from the postoccipital spine to tail, without evidence that those on middle 
of back appeared later than the others. In this specimen are rudiments of the 
additional ocular spines which appear later, one papilla being present above middle 
of orbit, a second over spiracle. In later stages the growth of these secondary 
ocular spines may be traced, their development being often accompanied by the total 
disappearance of the primary spines. The secondary spines may disappear in turn. 
The growth of the mid-dorsal series I have been unable to trace. Specimens show 
much variation with respect to their development. In one, 340 mm. long, no spines 
are present between the postoccipital spine and the tail. In another, the series is 
complete except the two immediately following the postoccipital spine, these two 
being still represented by dermal papille. 
In an embryo, 145 mm. long, the tail is produced 31 mm. beyond the second dorsal, 
and forms a depressed tapering appendage which becomes very slender toward the 
tip. The lateral folds and the median dorsal fold are continued some distance along 
this appendage, but are very low. Aside from this, there is no indication of the 
future caudal fin. Ina younger embryo, 125 mm. long, the unabsorbed yolk being 
still large (about 25 mm. in diameter), the tail is proportionately longer than in the 
last, 86 mm. in length, the terminal portion projecting 32 mm. beyond the dorsal fin. 
As in the first described, the lateral caudal fold is distinct, highest in the region of 
the dorsal fins, thence declining in front and behind, disappearing before reaching 
cither base or tip of tail. No trace is present of a median fold connecting the two 
dorsals. Such a fold appears to extend from second dorsal around tip of tail, becom- 
ing continuous with the anal fold, which is arrested definitely at a distance of 4 
mm. behind the vertical from second dorsal. The latter folds may, however, be 
exaggerated, or may be entirely due to the shriveling of the specimens. 
The youngest embryo described is light brownish in color, with a series of whitish 
or light-yellowish crossbars down the middle of back and tail. The same colors 
appear on pectorals in the form of rounded spots and blotches. A round black spot 
has appeared at base of each pectoral, surrounded by an area of light yellowish. 
In a second embryo, of about equal size, the bands on back of tail seem to bear a 
definite relation to the spines. In an older embryo, with the yoke nearly absorbed, 
the color has undergone Considerable modification. The bands and the lighter areas 
have disappeared, and the disk is sparsely covered with small, round black spots, the 
largest nearly equaling diameter of pupil. 
