Notes on the Sipunculida of Laguna 
Beach 
RALPH VY. CHAMBERLIN 
The following notes and provisional diagnoses are based upon a_ collection 
of Sipunculids made by Prof. Hilton at Laguna Beach in 1917. Six species are 
represented. 
SIPUNCULUS NUDUS LINN. 
One specimen of this widespread species was taken on the sand flats at low tide 
in August, Balboa. As preserved it is 26 cms. long. Attachments of nephridia and 
retractor muscles normal. The usual 31-32 longitudinal muscle bands. The body 
appears to be pigmented to some extent, as has also been recorded for a specimen from 
the Malacca region described as dark brown (Selenka), and one from Key West 
(Gerould). The species is known from various parts of the Atlantic along both shores, 
from the Mediterranean, Adriatic and Red seas, Malacca, Bismarck Archipelago, 
Philippines and Japan. 
PHYSCOSOMA AGASSIZII (KEFERSTEIN ) 
In the collection are six specimens of this well-marked species taken at low tide 
on sand flats at Balboa and Laguna Beach. ‘The species is otherwise known to occur 
along the California coast (e.g., at Monterey Bay, Mendocino, San Francisco, Crescent 
Citv) and northward (Vancouver Id.) as well as southward (Puntarena, Panama). 
It has also been taken at Loyalty Is., Ceylon, Laccadives and Maldives, and in the 
Atlantic on the coasts of the United States and Africa. 
DENDROSTOMA ZOSTERICOLA SP. NOV. 
This species belongs to the greup with but two retractor muscles. These have 
their origins in the posterior third of the body (in the type about 10 mm. from caudal 
end) and are well developed throughout and free to near insertions. The nephridia 
open at the level of the anus and are elongate and free. Contractile tube with numer- 
ous caeca. Tentacles strongly dendritic or arborescent, the terminal branches numerous. 
Introvert wholly lacking hooks. Skin brown or in part grey, set off into numerous 
areas, these transversely elongate in middle region, in the posterior more rectangular 
and longitudinally elongate. Entire body and introvert, excepting a short area proximad 
of tentacles, bearing moderately numerous, small, dark and rounded elevations which do 
not rise into true papillae; usually one of these to each cuticular area; of uniform size 
and abundance throughout. Body typically narrowed at both ends, fusiform. 35 mm. 
long behind anus and about 15 mm. to distal end of introvert. : 
Taken in eel-grass in September, 1917. 
Type—M. C. Z. 2, 181. 
DENDROSTOMA MYTHECA SP. NOV. 
The type of this species was found in eel-grass (Zostera) in the same original 
lot with the types of the preceding species. It is a smaller species of obviously different 
form. The body is widest at the pesterior end, followed by a much longer, narrower, 
