SPINNING FISHES 
7 
•0051 of an inch; the component strands are made up of fine 
homogeneous filaments adhering in parallel order. 
The spinning-habits of Apeltes qtiadmcus appear to have been 
first observed by Mr. \V. P. Seal about 1879. The nests, 
compared with those of Spinachia spinachia. are tiny structures ; 
but in manner of formation they are similar. Some of these 
nests were brought by Mr. Seal to Professor Ryder in 1881, 
from ditches along the Delaware below Philadelphia. After- 
wards this naturalist received, from the same collector, a pair of 
the fishes ; and of these the male obligingly completed a nest 
under observation. Ryder's account is as follows : — 
The male binds the nest together by means of a compound thread which 
he spins from a pore or pores behind the vent, while he uses his bobbin-shaped 
body to insinuate himself through the interstices through which he carries his 
thread with which he binds a lew stalks of Anacharis or other water-weeds 
together, bringing in his mouth every now and then a contribution of some sort 
in the shape of a bit of dead plant or other object, which he binds into the little 
cradle in which the young are to be hatched. The thread is spun fitfully, not 
continuously. lie will go round and round the nest for perhaps a dozen times, 
when he will rest awhile and begin again, or turn suddenly round and force his 
snout into its top with a vigorous, plunging motion, as if to. get it into the proper 
shape. Its shape is somewhat conical before completion, an opening remaining 
at the top. . . . The thread is wound round and round the nest in a horizon- 
tal direction in the case we are describing, and if this thread is placed under the 
microscope when freshly spun, it is found to be composed of very thin transparent 
fibres to the number of six or eight ; where they are broken off they have 
attenuated tapering ends as though the material of which they were made had 
been exhausted when the spinning ceased. Very soon after the thread is spun 
particles of dirt adhere to it and render it difficult to interpret its character. I 
have seen the thread being drawn out of the abdomen repeatedly, but not from 
the vent ; it appeared to me more probable that it came from the openings of 
a special spinning gland. Its glass-like transparency shows that it is not made up 
of ingested food, the particles of which would exhibit themselves were that the 
case. The nest measures half an inch in height andjthree-eighths in diameter. 
Upon opening the male I find a large vesicle trlled with a clear secretion which 
coagulates into threads upon contact with water. This vesicle . . measures 
one-fifth inch in length and an eighth in diameter. As soon as it is ruptured it 
loses its transparency, and whatever secretion escapes becomes whitish after being 
in contact with the water for a short time. This has the same tough, elastic 
qualities as when spun by the animal itself, and it is also composed of numerous 
fibres, as when a portion is taken which has been recently spun upon the nest. 
Ryder adds that possessing only a single male, he had not 
learned anything as to the origin of the secretion which he 
found in the vesicle, and he had obtained no precise information 
as to the opening through which the thread passed.*® After 
wards, however, in the light of the papers of Mdbius, he was 
satisfied that the vesicle was the bladder ; and that the thread- 
emitting pore was the urinary aperture.** 
Next to the nests of sticklebacks, perhaps the most 
‘® J. A. Ryder, “Notes on the development, spinning habits, and structure of 
the four-spined stickleback Apelles qnadracus," Bulletin of the United States 
Fish Commission, i. (1882), pp. 24-9. 
"J. A. Ryder, “The spinning habits of the adult male Apeltes quadracus 
during the breeding season,” Report of the United States Commission of Fish 
and fisheries, xiii. (1887), pp. 514-6. 
