142 WILLIAM BLAXLAND BENHAM. 
whereas, throughout the ceelom ova may be found; and even 
amongst the tentacles, where they are undergoing segmen- 
tation. 
In a transverse section (fig. 33) the ovary is seen to be 
composed of numerous rows of cells of different sizes, those 
nearest the blood-vessels being small, and the cells increasing 
in size as the distance from the vessel is greater, so that the 
various stages in the formation of the ova can readily be seen 
(fig. 34). The coelomic epithelial cells covering a vascular 
cecum enlarge; one of them increases more rapidly than its 
neighbours, and thus becomes surrounded by these as a cap- 
sule. The capsule-cells become smaller and flattened, and 
finally, when the ovum is fully grown, it escapes into the celom, 
leaving the capsule-cells behind. 
The testis is made up of a mass of sperm-morule, sur- 
rounded by or embedded in a stroma of smaller cells. Sperm- 
morulze are found in the celom, but I have not detected fully- 
formed spermatozoa. 
The nephridia serve as the genital ducts, as Dyster observed. 
I have seen ova quite close to the larger funnel, but have not 
seen any in the duct itself. 
II. Tue Srecies or PHORONISs. 
The name Phoronis was given, in 1856, by Strethill 
Wright (25) to some small vermiform tentaculated animals 
living in tubes, which were embedded in stone. The genus 
was formed for the reception of two species, one of which may 
be a young stage of the other. The latter is Ph. hippocre- 
pia, which has been fairly well described from living speci- 
mens by Strethill Wright, and Dyster (6). 
1. Ph. hippocrepia, Strethill Wright, 1856. 
Individuals small, not exceeding an inch in length. 
Tube membranous, embedded in coral or limestone. 
The lophophore is simple. 
Tentacles about sixty in number. 
