82 THE VOYAGE OF H.M.S. CHALLENGER. 



radiate manner. The mouth is situated on a more or less prominent conical projection of 

 the peristome, which may show a constriction at its base. There are five pairs of 

 mesenteries in the oral cone and three below. 



The ccenenchyma consists of the tissue uniting neighbouring zooids ; it contains a 

 system of canals which takes a direction chiefly at right angles to the axis of the stem, 

 and communicates with the bases of the individual zooids. 



Synopsis of Species. 



A. Spines all of one type. 



1. Stem stout, straight, or slightly flexuose; spines short, conical, and close-set, 



not hooked, very small on one side of the axis, and gradually increasing in 



length towards the other, distributed in irregular longitudinal rows, . . propinqua, n. sp. 



2. Stem stout, straight, flexuose or contorted ; spines conical, subequal, close-set, 



somewhat bent upwards, irregularly arranged, sometimes in transverse rows, . anguina, Dana. 



3. Stem not usually so stout, twisted into subregular spirals ; spines conical, 



arranged spirally, shorter on the inner than on the outer margin of the spiral 



axis, ......... spiralis (Linn.). 



4. Stem light brown instead of black, with six longitudinal rows of distant short 



spines, ......... paucispina, n. sp. 



B. Spines of two distinct types. 



5. Stem very long, not spiral ; large spines conical, elongate, pointed, and usually 



covered with small granulations ; small spines very slender and relatively 



elongate, distributed irregularly between the larger ones, . . . fiagellum, n. sp. 



6. Stem spiral, as in Cirripathes spiralis; large spines stout, cylindrical, with a 



blunt apex, arranged spirally; the interval between the large spines is filled 



in with a number of very short triangular spines with a sharp apex, . . diversa, n. sp. 



Cirripathes propinqua, n. sp. (PI. X. figs. 9-13; PI. XII. fig. 14 ; PI. XIV. fig. 7). 



Axis straight or slightly flexuose, not spiral, clothed with short, conical, closely set 

 spines, which are larger on one side of the stem than on the other. 



The type of this species is in the British Museum collection, and was received through 

 the Sydney Museum from Cape Moresby, New Guinea. The specimen consists of two 

 portions of the axis, each about 30 cm. long, densely clothed with ccenenchyma, in which 

 the polyps are imbedded. The soft parts are well preserved. The stem is about 3 "75 to 

 4 "25 mm. in diameter, somewhat irregular, but only slightly tapering in the parts 

 preserved. 



The spines are short, thick, and conical, with a blunt apex, and stand out at right 

 angles to the stem ; the apex is not curved upwards, as in Cirripathes anguina, and, 

 unlike that species, the spines are here of different lengths (PI. XII. fig. 14). On one 

 side they are very short, and gradually become longer towards the opposite side. The 

 longest are similar to the long spines of Cirripathes spiralis. From fourteen to sixteen 

 rows may be counted from one aspect, but in the thicker portions of the stem the spines are 



