' I 



■|-)„. j mi , nent has .1 transverse row ol more delicate spines or hairs and 



• • .... ide especiall) of the lower segments. 



righl side with both rami much shorter than those of the left side. 

 1 rus of the left side have 11 and 9 segments; form of the segments 



spines much like in the second cirrus. 



iiirth cirrus of the right side quite rudimentary, rami very unequal, both composed of 



with smal) groups of hairs al the extremity of tl lenl 1 >n the lefl side 



:. — d of two nearly equal rami composed of m segments. The fourth left 



. has the same structure as the left one of the fifth pair (PI. I. fig. 20): the groups of 



i :. dorsal side of the rami al the extremity of the segments and growing stronger 



in the terminal segments are very characteristic for both cirri. 



The right-hand cirrus of the fifth pair is extremely small, rudimentarj PI. I. fig. 21). Itdiffers 



from that of the fourth pair in having quite equal rami. They are composed of five segments. 



Both cirri of the sixth pair have a stronger ramus of 12 broader segments and a more 



slender ramus of 1 1 segments. llu\ bear, at the extremity of the segments towards the dorsal 



the same groups of stronger spines as in the left-hand cirrus of the .\' u and s' 1 ' pair: at tin ■ 



anterior or concave side. each segment bears as a rule one pair of spines or a larger spine 



impanied by two or three more slender ones. 



Caudal appendages (PI. I. fig. 221 shorter than the first segment of the pedicel 

 of the sixth cirrus. slender with a dense tuft of hairs near the extremity and a few hairs along 

 the sid' 



Penis cvlindrical, growine thinner towards the extremity, with very numerous and ven 

 delicate curved hairs scattered over its surface; a tuft of such hairs at the extremity. 



1 g g s numerous. long oval. Longest axis 0,2 to 0,22 mm., shortest axis 0,08 mm. 



This species was taken in half a dozen specimens, only two of which seem to be 

 full-grown, at : 



Stat. 253. December 10, 1899. Lat. 5 4S.2S., Long. 1 32 13 1".. Dcpth 304111. Bottom: gray 



clay. hard and crumbly. 

 Stat. 251. December 8, 1S99. Lat. 5 2S .4 S., Long. 13: o.: K. Dcpth 204 m. Bottom: hard 



coral sand. One small specimen. 



General Kern ark. This is a very remarkable species. Were it not for Dakwin's 



(Hinds' /'. eburneum. 1 would have feit greatly inclined to consider it as representing a new 



genus. As already observed l>y Hinds :who therefore propose.1 the name Trilasntis for this 



Cirripedi and as described in detail by Darwin, the terga are "entirely" absent in /'. eburneum 



and at tirst I did not find them in /'. obliquum either. Yet on studying the capitulum more 



illy, I discovered the terga tremely minute triangular pieces, hidden in the folds oi 



: membrane uniting the two scuta over the upper end of the carina. In this regard the new 



'turn with its quite rudimentary terga bridges the cleft which separates /'. crassum 



with small (DARWIN says "rudimentary" terga — luit they are well-developed and even large 



with those of /'. obliquum] terga and /'. eburneum with no terga whatever. 



of the parts composing the mouth in /'. obliquum differs in several regards 



1 ; 



