MUSEUM OF COMPARATIVE ZOOLOGY. 109 
Observations. 
Plate I. Figs. 1-23. 
The material upon which my observations were made was collected at 
Eastport, Maine, in the summer of 1885. Adult Ophiopholes were 
dredged off Friar’s Head, Campobello. Great numbers were taken just 
below the line of low tide on Clarke’s Ledge, near Eastport. 
The following observations on the development of the egg were begun 
after its fertilization, and after it had been laid. 
Ova were voluntarily cast by the female on the 17th of August. They 
were found in multitudes at the bottom of the glass dishes in which the 
adults were confined, forming a greenish or yellowish cloud discoloring 
the water. A white fluid of spermatozoa was also found in another dish 
containing males. As both elements are cast in the water it is probable 
that in this species fecundation occurs outside the body,* as is generally 
the case among Echinoderms. The ova of Ophiopholis, like the adults, 
appear to be very hardy, and very little care is necessary to keep them 
alive. The contact of sperm and ovawas not observed. The white fluid 
containing spermatozoa was mingled with fluid containing ova, and it is 
thought that artificial fecundation was thus effected.t The ova began 
to develop soon after. Fecundated ova were also found in water in 
which many Ophiopholes were living. 
Each egg, Pl. I. fig. 1, is enclosed in a transparent capsule .13 mm. in 
diameter. ‘This capsule in the first stages observed was not thick as in 
the viviparous genus, Amphiura, but very thin. It is thought to be 
homologous with the outer layer, m c., mentioned and figured in Metsch- 
nikoff’s account { of the development of A. sqguamata. Its thickness 
may have been greater in younger stages. The eggs are not laid in 
bunches, masses, nor were they observed to be cemented together. They 
were not observed to develop in pouches, although pouch-like parts of 
the genital glands, ovaries, are sometimes squeezed out through the geni- 
tal slits as in the genus, Gorgonocephalus. When the ova were first 
examined segmentation had not begun, but no germinative nucleus was 
seen. Each egg in the youngest stage, Pl. I. fig. 1, has the yolk com- 
* In Amphiura fecundation takes place in the body, teste Apostolides, Metsch- 
nikoff, and others. 
t Metschnikoff (Zeit. f. Wiss. Zodl., XLII. p. 664), artificially fertilized Ophio- 
thrix fragilis. 
t Op cit., p. 14. Plate III. Fig. 3. 
