REPORT ON THE ALCYONARIA. 123 



the larger branches one of 25 mm., the terminal branches have a basal diameter of 

 \5 mm., and an apical one of 2'2 mm. The coenenchyma is thin, but provided with a 

 layer of large spindle-shaped spicules. The polyps are found chieHy on one surface, and 

 on the margins of the stem and of the twigs of the colony, while the other portions of 

 the surface are covered only with the coenenchyma. The distance between the polyps is 

 from 1 to rS mm. On the thickened and flattened ends of the branches there are two 

 opposite polyps. The polyps present an erect, wart-like body, with a broad base of a 

 diameter of I'S mm., and a height of 0'8 mm., they are closed by an imperfect operculum. 

 The spicules are mostly discernible by the eye. In the ccenenchyma tliey are somewhat 

 flattened spindles, whose margins are furnished with dentations, which can intei-calate 

 with those of the neighbouring spicule. Sometimes, especially towards the base of the 

 polyps, they expand into longish discs truncated on both sides, or running out into short 

 prominences. Their surfaces are covered with rough wart-like protuberances. The 

 longest spicules have a length of 3 mm., with a diameter of 0"2 mm. ; others measure 

 r3-0'5 ; 0'9-0"3 mm. On the polyps the spicules are discoid, arranged in the form of 

 a ring, sometimes triangular, sometimes rhomboidal ; towards the margin of the calyx 

 they are scale-like, and the protuberances often take the form of uonibdike teeth. Their 

 thickness difl'ers very much ; their length by breadth is 0'9-0'3 ; O'4-O 3 mm. 



The operculum is formed of smooth, scaly and dentate spicules, which are found in 

 the basal portions of each tentacle ; these are at once distinguished Ijy their violet colour, 

 which contrasts with the white spicules of the body. Sometimes tliese are spear-shaped ; 

 sometimes they remind one of the Stachelplatten of Paramuricea. Their length by 

 breadth, i.e., the greatest diameter, is 0-54-0-41 ; 0-4-0-2 ; 0-26-0-07 ; 0-2-0-05 ; 

 0'33-0'16 mm. An incomplete ring of curved blunt .spindles forms the colleret. The 

 axis is horny, rigid, and of a brownish-yellow colour ; it is very feebly flexible. The 

 colour of the coenenchyma and of the polyps is white, but the oral region is of a dark 

 violet. From Acis orientalis, Ridley, to which this species is nearly related, it may be 

 distinguished l)y the form of the spicules and by the compressed stem. 



Habitat. — Station 232. the Hyalonema-gTOxmd, Japan ; depth, 345 fathoms ; bottom, 

 green mud. 



Genus 12. Muricella, Verrill. 



Muricella, Verrill, Trans. Connect. Acad., vol. i. p. 4.50, 1869. 



Verrill {loc. cit.) subdivides the genus Muricea, as emended by Kolliker, into three 

 divisions. One, Muricella, comprises the East Indian .species ; tlie species of the other 

 two, Muricea and Euminicea, being chiefly limited to the Atlantic Ocean and to 

 the West American coasts. But Muricella, at least, diflers so much from the others 

 that we feel justified in keeping it generically apart ; a conclusion adopted by Ridley. 



