A Variant Aplysia calif or nica 
Lindsay R. Winkler 1 
On July 6, I960, while on a routine collect- 
ing trip to Lunada Bay, Palos Verdes, California, 
I collected an unusual 19. 5 -cm sea hare. This 
sea hare had all the characteristic features diag- 
nostic of Aplysia calif ornica Cooper. In addition, 
however, a row of fleshy hornlike tentacles 
extended from 1 cm behind the posterior ten- 
tacles on the middorsal surface for a distance 
of 1.5 cm, after which the continuation of this 
line was outlined by a row of bumps extending 
caudad to its interception with the genital 
groove between the anterior ends of the para- 
podia. The specimen was transported live to 
the laboratory where it was observed and photo- 
graphed (Fig. 1). 
On this specimen the posterior tentacle mea- 
sured 2.5 cm. Beginning anteriorly, the first 
three supernumerary tentacles measured 9, 7, 
and 8 mm, followed by a branched tentacle 
with a total length of 8 mm, each branch of 
which measured 3 mm. The most posterior 
tentacle was short, measuring only 3 mm in 
length. 
Careful search of the Lunada Bay area at 
the time and on successive trips to the area dur- 
ing the next two years, though resulting in the 
capture and examination of hundreds of speci- 
mens, failed to produce others possessing aber- 
rant tentacular configurations. 
It is felt that this specimen is probably the 
result of an accident of development, in which 
cells normally destined to become tentacles were 
moved caudad to develop into supernumeraries. 
Credence may be lent to this hypothesis by the 
elongated incurved cavities on the right-hand 
side of tentacles 1 and 3, which suggest the 
"rolled-tube” effect which is normally seen in 
the posterior tentacle of the sea hare. Wong 
(Chi) and Wagner (1956) demonstrated 
1 College of the Desert, Palm Desert, California 
92260. Manuscript received December 18, 1966. 
morphological changes in snail tentacles after 
experimental irradiation with ultraviolet light. 
This may indicate a plasticity in snail tissues 
which, although not indicating any mechanism, 
could conceivably be remotely related to the 
present phenomenon. 
It is not possible, however, to eliminate the 
possibility of the phenotypic appearance of a 
Fig. 1 . Photographs of the tentacles of the ab- 
normal specimen of Aplysia californica, taken while 
living. Note the fleshy platform supporting tentacles 
2 and 3. 
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