The nudibranch family Dironidae. at 
laterals widely separate from it. First jateral depressed, of moderate 
size, denticulate on inner face, second lateral large, compressed, 
simply hamate. 
Dirona pieta MacFarLanD Sp. Nov. (and Genotype). 
(Plate 30 Fig. 1, Pl. 31 Figs. 1—10, Pl. 32 Figs. 20, 22—24). 
Dirona pieta MACFARLAND, ELIOT in COCKERELL and ELIOT, Notes on 
a Colleetion of Californian Nudibranchs, in: Journ. Malacology, 1905, 
Vol. 12 (3), p. 45—48, Pl. 7, figs. 6—11. 
Body form stout, somewhat limaeiform, abruptly rounded in front, 
posteriorly tapering to the tip of a rather short tail. Dorsum 
slightly rounded, sloping rapidly behind the heart region, less so 
in front. Head broad, squarish, its margin expanded into a broad, 
undulating veil. Foot elongate, bluntly rounded in front, squarish, 
tapering posteriorly to the short tail, which is about one third of 
the body length. 
Rhinophores without sheaths, direceted forward and outward, 
clavate, the clavus irregularly perfoliate, one-third to one-half the 
length of the whole organ. ÜCerata lanceolate, inflated, slightly 
flattened antero-posteriorly, non-caducous, arranged in closely-set 
irregular series along each side of the dorsum, converging in front 
toward the median line, but not meeting, thus leaving a small area 
free from cerata. Cerata rows meeting posteriorly above tail. Inner 
surface of the cerata tuberculate, the elevations often being con- 
fluent into a median longitudinal ridge with short irregular branches. 
Outer surface less tuberculate. Largest cerata one-third to one-half 
the length of the animal, innermost in position, the shorter ones 
arranged externally to them. Cerata not containing branches of 
the liver. 
Reproductive openings two, not conspicuous, situated as usual 
in Aeolidiadae. Renal opening close up to outermost cerata a short 
distance behind the reproductive openings. Anal opening at the 
summit of a conical papilla, far back on the right side, in the line 
of the outermost cerata. 
Color (Pl. 30 Fig. 1) reddish yellow to brown, the dorsum sprinkled 
everywhere with fine yellowish-white, olive green, and pink spots. 
In the middorsal and lateral region the dark olive green liver shows 
conspicuously through the integument. 
Total length up to 40 mm, width 7 mm, height 7 mm. 
