36 Coelenterata. 



According to M(iller( 3 ) Corallium possesses an axial epithelium of ectodermal 

 origin, thus agreeing with the Gorgonids. The axial skeleton is formed by 

 the cementing together of mesogloeal spicules by the secretion of crystalline 

 calcareous masses. The mesogloeal spicules are enabled to unite with the axial 

 skeleton owing to separation of the neighbouring cells of the axial epithelium, 

 which afterwards assume their former positions. 



Muller( 2 ) traces the history of Rhizoxenia. According to the rule of priority 

 R. should be designated Zoantha Lesson, but the author, adopting the name 

 associated with the first adequate description, retains R. Sarcodictyon catenata 

 agrees so closely with R. rosea that the former genus is merged with the latter, 

 which is thus defined - Colony formed by basal stolons which may unite to 

 form plates; polyps retractile, single or in small groups on the stolons, ten- 

 tacles turned in on retraction, the basal part of the polyp has no horny cu- 

 ticle. 



Nutting (') gives a revision of the Muriceidse, and describes the collection 

 made by the >Siboga. Superficial characters are comparatively useless in de- 

 fining the genera; the form and disposition of the spicules provide the most 

 reliable characters, occasionally the shape and size of the calices are of value 

 but only rarely does the mode of branching assume generic importance. The 

 primitive form of spicule in this family is the spindle, which is the only 

 form found in all the genera; the complex spicules of Echinogorgia, Acampto- 

 gorgia and Heterogorgia are at first spindles. The author describes 9 forms of 

 spicnles, derived from the spindle by modifications in different directions, which 

 are the dominant types characteristic of Echinomuricea, Echinog., Thesea, 

 Acamptog.j Placogorgia, Bebryce, Heterog. and Villogorgia. In a single slide of 

 F. spicules of almost all the types may be found. A key is given to the genera 

 and the following are described Acanthogorgia 12 (3 n.), Anthomuricea 4 n., 

 Anthogorgia 2 n., Muriceides 3 n., Muricella 7 (4 n.), Versluysia n. (for Muricella 

 ceylonensis and ramosa and 5 n. sp.), Acis 4 (3 n.), Elasmogorgia 1, Menaf- 

 cella 1, Bebryce 3 (1 n.), TJiesea 7 n., Echinomuricea 7 (5 n.), Echinogorgia 6 

 (3 n.), Acamptogorgia 1 n., Placogorgia 11 (10 n.), Villogorgia 8 (4 n.), Menella 

 2 n., Heterogorgia (including Astromuricea) 9 (7 n.). Seventeen species of Muri- 

 ceidse were obtained at one station, other stations yielded 14, 13 and 11 species 

 respectively. Muriceids are much less abundant in the deep sea of the region 

 explored than at a depth of less than 200 m. The relationships of Muriceids 

 seem to be closest with the Plexauridse, but in the former the ccenenchyme is 

 thinner and the canals around the axis are irregular both in section and dis- 

 position, while in P. they are round or oval and form a symmetrical series. - 

 See Nutting (V). 



Nutting ( 3 ) describes the Isidse collected by the Siboga, namely, Isis 2 (1 n.), 

 Ceratoisis 4 (1 n.), Acanella 3 (2 n.), Mopsea 2 n., Peltastisis n. 2, which com- 

 bines the jointed axis of the Isidse and the characteristic operculum of the 

 Primnoidse, and resembles the latter in its spiculation. The Isidse stand closest 

 to the Primnoidse but show characters in common with the Melitodidse, but the 

 axis provides a differential character in both cases. The species of Isis were 

 taken in shallow water (22-45 m.), the others in deeper water. 



Nutting (') remarks that several species of Juncella and Scirpearella exhibit 

 two colour phases, red and white, or red and yellow, which do not seem to 

 be correlated with sex or age. The author regards as of great systematic value 

 the girdled spicules*, that is, those in which the spindle is free from ver- 

 rucse at its middle. The basic form of this spicule exhibits 6 symmetrical 

 and 5 asymmetrical modifications, certain of which predominate in a given 



