480 MOLLUSCA. 
tum: caput oblongum corpore angustius: brachii sessiles curti, crassi, 
pro longitudine 2, 4, 3, 1: brachii tentaculares equé ac corpore longi, 
triente extremo dilatato-lanceolato, series quatuor acetabulorum gerente : 
os magnum, cupuliferum : tunica brunneo-purpurascens rufo-punctata, 
infra pallidior. 
Body elongated, ovate-lanceolate, tapering gradually backwards to 
a blunt point. Fins broadest at about the posterior fourth, where, to- 
gether, they equal the width of the body, thence tapering in each di- 
rection gradually, and without any angle or dilatation. Colour dark 
purple brown above, paler beneath, everywhere finely punctate with 
dark brown dots. Head narrower than the body, longer than broad. 
Sessile arms rather short and stout, armed with two rows of cupules; 
the superior pair shorter than the head; the first lateral pair a third 
longer than the superior, and somewhat longer than the head; the 
second lateral pair a little longer than the first; the inferior pair nearly 
equal to the second lateral; tentacular arms nearly as long as the body, 
compressed, the distal third having a lanceolate dilatation, bearing four 
rows of delicately pedunculated cupules, armed at the margin with 
delicate black crochets. Mouth large; lip folded and projecting, with 
two or three minute cupules at each fold. 
Length of body, six inches; of head, two inches; of superior arms, 
two and a half inches; of inferior lateral arms, three inches; of tenta- 
cular arms, eight inches; of cup-bearing portion, two and three-fourths 
inches; greatest breadth two and a half inches. 
From the island of Maui, Sandwich Islands. 
It closely resembles S. loliginiformis, D’Orb., from the Red Sea, 
which has a much more decided expansion of the fins at its posterior 
half, and the tentacular arms are much shorter. The narrow and regu- 
larly tapering fin is its distinguishing character. Described from 
specimens in spirits. 
Figure 593, the animal, with details. 
OMMASTREPHES INSIGNIS (Gould ). 
Corpus magnum, subcylindraceum, posticé angustatum: pinna trientem 

