EUPOLYMNIA REGNANS. 4:« 



EUPOLYMNIA REGNANS, sp. nov.^ 



Plate 79, fig. 1-3. 



The color is a nearly uniform greyish yellow throughout. 



The general form is cylindrical, but with the venter more or less flattened. 

 One specimen, exclusive of its tentacles, has a total length of about 230 mm. and 

 a maximum width across the thorax, exclusive of the parapodia, of 11 mm., this 

 being at its caudal end, the thorax considerably narrower in the branchial region. 

 Abdomen narrowing caudad to a width of about 4.5 mm., a little in front of the 

 caudal end. When extended the tentacles are at least 75 mm. in length. Total 

 number of somites one hundred and thirty, of which one hundred and ten belong 

 to the abdomen. 



The prostomium forms an upper lip, from the caudal portion of which, 

 above and extending to the ventral surface, arise the very numerous long tenta- 

 cles. Back of the tentacles is an elevated region, or transverse fold, on which 

 are numerous minute eye-spots. The tentacles are relatively slender. Each is 

 marked with the usual longitudinal ciliated groove. 



The peristomium presents on the ventral side just caudad of the mouth a 

 curved transverse piece, or collar, of which the convexity is cephalad. 



The second, third, and fourth somites bear each a pair of arborescent 

 branchiae. Each branchia has a stout trunk, from which arises a large branch 

 which often nearly equals the main trunk in size, thus giving to the branchia 

 the appearance of being bifurcate. Each of the two principal branches bears 

 a number of smaller branches subdividing into filaments that form very dense 

 heads and together have an appearance not unlike that of a head of cauliflower. 

 The branchiae decrease in size from the anterior pair caudad. 



Segmental papillae are present on the sides of somites III, IV, V, VI, VII, 

 and VIII, those of the last three being more weakly developed than the others. 



Setae begin on the fourth somite and uncini on the fifth. 



The ventral plates are eighteen in number. Of these, the anterior are short 

 anteroposteriorly and transversely elongate, the succeeding ones regularly 

 decreasing in width and filling the space between the ventral ends of the uncinig- 

 erous tori, and at the same time increasing in length, the outline formed by 

 the plates together being narrowly triangular, with apex caudad. A transverse 

 furrow divides each plate into a narrow anterior portion and a broader posterior 



' regnare, to rule or reign. 



