NOTES ON THE GENUS MONSTRILLA. 571 
which are often spirally twisted together (fig. 8). When the 
set are double they do not generally extend far beyond the 
furcal sete. In M. longispinosa the genital opening is 
situated at the base of a ventral projection, from which pro- 
ceeds a stout median seta; this seta is single for the first part 
of its course and then bifurcates to form two long setz similar 
to those in other species. In this case the genital seta is more 
than one and a half times the length of the animal. In the 
males the genital aperture is situated on a conical ventral pro- 
jection, and this is provided with a pair of foliaceous lappets, 
as shown in fig. 9. These organs, which at first sight appear to 
be peculiar to the genus, can, I think, be nothing more than an 
enormous development of the genital armature found in many 
Copepoda, especially in the genera Eucheta, Cyclops, Cantho- 
camptus, and many Calanide (see Claus, op. cit. p. 65). 
According to Claparéde the genital appendages of the 
female serve for the attachment of the ova during the earlier 
stages of development, and he figures a female bearing a mass 
of ova in this position. I have had some difficulty in deter- 
mining whether these are really ova on the spermatophores of 
the male, since I have not been able to procure specimens 
with masses of “ova” attached. From the study of a female 
of M. rigida which bears a few of these bodies, and from 
observations communicated to me by Mr. Sinel, I have little 
doubt that Claparéde describes them correctly. At the time 
of their attachment they are surrounded by a mass of 
gelatinous matter which serves to attach them to the genital 
sete. 
Of the internal anatomy of Monstrilla there is little to be said. 
Excepting for the mouth and pharynx, which have already 
been described, the alimentary tract is altogether aborted. 
The cellular cord which passes from the pharynx appears to be 
attached to the sheath of the nervous cord at the place where 
the esophagus, if present, would pass between the connectives 
of the former. 
Claus has called attention to the remarkable fact that in 
the female, when the ovary is not distended, the body wall is 
