402 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
pared the Puget Sound specimens with some in the Museum of 
Comparative Zoology from Massachusetts Bay, and find them iden¬ 
tical in every respect. 
Euphrosynidae. 
19. Euphrosyne heterobranchia sp. nov. PI. 6, figs. 60-66 
a-c. 
Form elliptical, robust, slightly more tapering towards the pos¬ 
terior than towards the anterior extremity. Dorsal bare stripe 
narrow, less than one fourth the width of body. Somites, 34. 
Caruncle (Fig. 60) Low, bilobed dorso-ventrally, the lobes of 
equal length, reaching sixth somite. It has eight longitudinal 
ridges, two pairs in the upper, and two in the lower lobe, extending 
the entire length of the caruncle. Median tentacle short and awl- 
shaped, its filiform tip nearly as long as the thick basal portion ; at 
its base the two posterior or “dorsal” eye-spots. The anterior or 
“ ventral ” eye-spots confluent, flanked on each side by a very minute 
antenna. 
Palpi rather broad and flat, separated by a slight furrow from first 
and second somites, divided by a conspicuous median cleft. The 
mouth bordered posteriorly by the 5th somite. 
Parapodia of usual form in this genus. A short ventral cirrus at 
posterior edge, adjacent to the intersegmental furrow; a lateral cir¬ 
rus between the fourth and fifth gill-trunks, counting from the upper¬ 
most of the series; a stout, fusiform dorsal cirrus, not exceeding the 
branchiae. Branchiae ten on each side, some simply forked, others 
ramose, branching twice (Figs. 66 a-c). Setae all with hard, glisten¬ 
ing tips; the bifid ones of dorsal series often have a very minute 
lateral tooth (Fig. 63) ; lateral tooth of ventral series also small 
(Fig. 65) ; cleft setae both serrate and non-serrate (Figs. 61-62a), 
the latter form the more common ; serrations sometimes very few. 
Length , 13 mm.; width, not including setae, 4.5 mm.; dorso- 
ventral thickness, 33 mm.; median base stripe, 1 mm. 
A single specimen in the Columbia collection. The species is 
interesting for its resemblance to F. borealis of the North Atlantic, 
as to the heterogeneous character and large number of its bran¬ 
chiae, but differs from it in the shape and multiform nature of 
its setae, and in the larger number of somites. It is sufficiently dis- 
tinct from all other known species of our Pacific coast, although its 
superficial resemblance to Euphrosyne arctia is rather striking. 
