198 Edible Mollusca of the Oregon Coast 
zoa but no activity of the latter. Insufficient observation through 
the year renders impossible an assertion, at this time, regarding 
the spawning season of this species on the Oregon coast (Fig- 
Uikeae Vlas 2.520) 
7. Saxidomus giganteus Deshayes. 
The spawning period of this species has not been fully deter- 
mined for the Oregon coast. Sections of the ovaries prepared in 
March, June and November show little difference in the develop- 
ment of the ova. Spermatozoa have been found to be fully 
formed in March, June and November but in no case have I 
observed them in an active condition. A closer examination 
throughout the year will be necessary to make a positive state- 
ment regarding the spawning season of this species. 
The ova of Saxidomus are characterized by a very thick 
membrane which envelops each egg, and the large amount of 
connective tissue separating the follicles of the ovary are also 
distinctive features. The spermatozoa are elongate, curved, simi- 
lar to those of Papliya staminea, (#igures Vil Ayes One ae 
8. Macoma nasuta Conrad. 
The spermatozoa of this species are mature and active during 
the latter part of March on the Oregon coast. Sections of the 
ovaries at this time indicate, however, a considerable number of 
immature ova. Spawning probably occurs in the late spring or 
early summer months (Figure VI, 8, 9). 
g. Mytilus edulis Linnaeus. 
On March 25th, at Yaquina Bay, the mantles of this species 
were found to be well filled with fully developed spermatozoa 
none of which, however, were in an active condition. Ova at 
this time were immature. Examination of the species at Sunset 
Bay on September 23rd indicated that the spawning season had 
just passed. At this time the bodies and mantles of the mussels 
were very soft and watery being in a spent condition. In both of 
these instances the specimens were taken from localities with 
exposure to the open ocean. The evidence seems to indicate that 
