SOUTHERN CALIFORNIA ACADEMY OF SCIENCES 21 
THRACIIDZA 
Genus Asthenotherus Carysentes 
Asthenothaerus villosior Dall. 
San Diego Bay, dredged by Prof. Kelsey. Identified by Fred 
L. Button, Esq. of Oakland. 
Structural and systematic conchology by George W. Tryon, 
Vol. III, page 144, deseribes this bivalve and gives *‘Cape St. 
Lueas, Li. Cal.,’’ as its habitat. 
TEREDIDZ: 
Genus Xylotrya Leach 
Xylotrya pennatifera, Blain. 
In a big pile at San Pedro. This pile was from timber sup- 
posed to have been from Oregon. This specimen was identified 
Pye Won. El. Dall. 
‘Sts. of Fuca to San Francisco,’’ Cooper, Geog. Cal. Moll. 
APLYSIIDA 
Genus Tethys Linneé 
Tethys (Neaplysia) ritteri Cockerell 
At Crescent Beach, San Pedro Bay I found this species or 
variety of our Aplysia with the more common A. californica 
Cp. during the winter of 1904. I have sent the radula of this 
species to the well known English specialist, Prof. H. M. 
Gwatkin, but have not received the microscopic mount of it. 
If the radula should prove to be distinct from Dr. Cooper’s 
species it would give value to a specific rather than a varietal 
one. Prof. Cockerell says of it, ‘‘This animal has the struc- 
ture of T. Californicus (Cooper) which was also described from 
San Pedro, but the color scheme is so entirely different that 
it must be assumed that the species are distinct. Should any 
reason hereafter appear to the contrary, T. ritteri will at least 
be a very distinct variety.’’ (The Nautilus Vol. XV., page 90.) 
Prof. Cockerell’s description, excepting the color scheme, shows 
no marked difference from some of Cooper’s californica. The 
fluid of T, ritteri is of a most beautiful reddish purple or violet 
eolor. A stain upon white paper has remained for months a 
rosy purple. The original description is given in the volume 
just referred to but for the use of the generic name ‘‘Tethys’’ 
rather than ‘‘Aplysia’’ see Dr. Henry A. Pilsbry’s paper ‘‘On 
the Status of the Names Aplysia and Tethys,’’ (Proce. Acad. 
Ceie. Phila. 1895, pp. 347-350). For the Family Aplysiide con- 
sult Pilsbry’s continuation of Tryon’s Man. Conch. Vol. XVI, 
1895-6. 
