68 • NATURAL HISTORY OF KERGUELEN ISLAND. 



ECIIINODERMATA. 



HOLOTHUEIOIDEA. 



PEI^TACTELLA, g. n. 



In general appearance like Fentacta, but destitute of calcareous 

 plates around the oesophagus, and having a distinct muscular gizzard. 

 Tentacles ten, arborescent, nearly all equal in the typical species. Suck- 

 ers in five double rows ; the intervening spaces smooth. 



Pentactella L^viaATA, Verrill, s. n. 



Body elongated, fusiform, rounded, with thin integuments. Suckers 

 alternating in two rows in each zone, not crowded, larger and more 

 numerous in the three lower zones than in the two upper. Cloacal 

 orifice with small and inconspicuous papillae. Tentacles ten, subequal, 

 elongated, much divided arborescently from close to the base. Three 

 very elongated vesicles, much dilated in the middle ; slender at tips, 

 where one of them is forked. CEsophagus not surrounded by any cal- 

 careous plates, with the first portion for about half an inch cylindri- 

 cal, minutely papillose externally. This is followed by a distinct, 

 rounded gizzard, smooth externally ; beyond this the intestine is con- 

 stricted, but soon expands into the wider part, which is long and con-' 

 voluted, with two principal folds, so that it is about three times the 

 length of the body. Two arborescently branched respiratory organs ; 

 one of them smaller than the other, with its numerous terminal branches 

 among and around the ovaries ; the branches of both are elongated and 

 slender ; the ultimate ramuli are also elongated and often dilated at the 

 tips. Ovaries in a large cluster ; the numerous tubes are simple and 

 more or less moniliform, about half an inch long. The retractor mus- 

 cles are well developed and extend from the base of the tentacles nearly 

 to the posterior end. The cloacal cavity is large. The calcareous plates 

 of the skin are few in number, minute, and widely scattered, irregularly 

 rounded, with lobed or creuated edges, and perforated by four to eight 

 or more rounded pores, of which two or four primary ones are largest. 

 The smaller plates are often four-lobed, the lobes rounded and each of 

 them perforated by a roucded pore, with narrow interstices, two of the 

 pores often larger ; this is perhaps the primary form, from which, by 

 additions to one or several parts of the border, the somewhat larger and 



