250 MOUDIDJE. 



Calliopaea (?) fuscata.* 



Plate XVI. Figs. 218-221. 



Animal semi-cylindrical, attenuated behind, dark slate-colored; head not distinct, 

 excavated in front, tentacles two, long, pointed ; branchiise long, club-shaped, slen- 

 der at base, alternating in two parallel rows on the two posterior thirds of each side, 

 the lower series much the smaller; foot bi-lobed in front, contracted posteriorly. 



Animal semi-cylinclrical, gradually attenuated behind, dark slate- 

 colored above, nearly black, punctured, an area running backwards 

 from each tentacle, and the posterior aspect of the tentacles drab, 

 near the posterior part of which area is the distinct black ocular 

 spot; on the anterior face of the tentacles is a black line which 

 passes down the outer margin of the face. Head not distinct from 

 the body, a little excavated in front, and capable of protrusion con- 

 siderably beyond the foot. Tentacles two, near the vertex, long 

 and pointed. Branchiae long, club-shaped, quite slender at base, 

 black, white at tip and insertion ; an upper row of four on each side 

 begins about one third down the body, growing shorter towards the 

 tail, and a lower series of five or six very much smaller ones ar- 

 ranged alternately with the upper ones. Foot pale ochreous, bi-lobed 

 in front, contracted posteriorly. Length, three tenths of an inch ; 

 breadth, one thirtieth of an inch. 



Found on logs in a mast-yard, Boston, July 22, 1842, 

 Tliis curious little animal bears no resemblance to any other in 

 the books, excejyt CalUopcea bellula, D'Orbigny, which has a broader 

 form, more robust and equal-sized branchiaj, which begin directly 

 behind the ocular spots, and are covered with large dots or tubercles. 

 It is even doubtful if they belong to the same genus, as D'Orbigny 

 describes Calliopcsa as having no tentacles, but two very long buccal 

 appendages. In our species the tentacles or vibracula are distinctly 

 u])on the head, and could not be mistaken for labial prolongations. 

 The white area enclosing the eyes and tentacles, in both instances, 

 is a remarkable coincidence, and one is inclined to think that D'Or- 

 bigny's animal was not well observed as to the want of tentacles, 

 and perhaps as to the part of the body occupied by tlie branchioe, 

 and that the two animals belong to the same genus and perhaps to 

 the same species. The transparent tip of the branchia) gives the 

 branchiae the appearance in certain lights of being hollow. The 

 motions of the animal are remarkably rapid, as Avell as the manner 

 in which the branchiae are tossed in all directions. The ova are de- 

 posited in little oval clusters. 



* See second note to page 243. 



