TWO NEW SPECIES OE THE PHORONIDEA. 
271 
he is unable to discover any points by wliich tliey can be 
differentially diagnosed, pointing out (9, p. 582) that the 
length and number of the tentacles vary tremendously from 
one season of the year to another. 
I therefoi’e assume that both Ph. ijimai and Ph. kowal- 
evski are encrusting varieties of Ph. hippocrepin, and from 
a comparison of specimens and sections of the latter and from 
descriptions given by other writers I conclude tliat there are 
several important anatomical differences separating it from 
Ph. van con verensi s . In the absence of any definitely 
formulated featm-es by which the various forms included in 
the genus Phoronis may be separated, I think that such 
amatomical characteristics must be far more important from 
a systematic point of view than such variable details as size 
and number of tentacles. 
C ha. rac ter 1 s t i cs of Phoronis vancouverensis, which 
it is suggested should distinguish it from Ph. hippocrepia 
a,nd its varieties : 
(1) The character and gi’eater development of the fascicles 
of longitudinal muscles. 
(2) Tlie presence of two nerve-cords in the anterior region 
of the body. 
(3) The structure of the diaphragjii. 
(4) The well-developed band of specialised cells in the 
pregasiric region. 
(5) Tlie possible separation of the sexes (dioecious), or, if 
monoecius, then ])rotandrous. 
II. Phoronopsis harmeri n. sp. 
This animal is placed in the genus Phoronopsis, established 
by Gilchrist (7) to include tlie form Phoronopsis albo- 
m act! lata described by him from South Africa, on account 
of the following characteristics : 
(1) The nerve-ring lies in an involution of the epidermis. 
(2) Only the left nerve-cord is developed. 
(3) 'I'he longitudinal muscles of the body are in numerous 
well-developed fascicles. 
