7. Anthozoa (incl. Hydrocorallia). B. Alcyonaria. 39 



(Stachyptilum). P. verticillata, polyps in whorls (1) on the whole rachis, 

 (a) close together, Scleroptilidse (Calibelemnon , Scleroptilum), (b) far apart, 

 Chunellidse (Amphiacme, Chunella], (2) only on the upper part of the stem, 

 forming a cluster, Umbellulidse (Umbelhda). P. penniformia, with polyps in 

 lateral masses or leaves, giving a pinnate arrangement, (1) rachis thin and long, 

 Virgulariidse, subfam. Pavonariinse with polyps in transverse rows, not in leaves 

 (Pavonaria), subfam. Virgulariinae , polyps in transverse rows of clusters or 

 leaves (Acanthoptilum, Scytalium, Scytaliopsis, Stylatula, Virgularia], (2) rachis 

 thick, (a) spicules three-winged, Pennatulidse (Pennatula, Leioptilum), (b) spi- 

 cules needle-like, Pteroeididse (Pteroeides, Struthiopteron, Sarcophyllutn}. The 

 authors place the P. radiata at the base of the order as they show primitive 

 characters e.g. the radial arrangement of polyps and the absence of axis in 

 many cases, for instance, in all Echinoptilidse; the Veretillidse also show primi- 

 tive characters in their spicules, which are rods or discs (not three-winged) 

 and in their canal system. From Ech. the Renillidae are derivable, by dorso- 

 ventral flattening of the rachis, which is already seen in Echinoptilum, the 

 naked ventral area on the rachis of which corresponds to the naked side of 

 Eenilla; the general organisation, the canal system, the compact arrangement 

 of the siphonozooids in groups between the autozooids, and the absence of 

 axis in these two families, show their affinity. From the Ver. have arisen the 

 Kophobelemn. and the rest of the P. bilateral! a. The form of the spicules 

 shows that Mesobelemnon is at the base of the family stem, and from it 

 Sclerobel. and Kophobel. have been evolved. From the last named sprang 

 Protoptilum and from this, by reduction of the autozooids to two longitudinal 

 rows and the reduction in number of the siphonozooids, Distichoptilum arose. 

 Parallel to these arose the Anthoptilidse and, from the Protopt., the Stachypti- 

 lidse in which the polyps stand in transverse rows. The Funiculinidse occupy 

 an isolated position, in them there is no dimorphism, which is a secondary 

 condition, and they have other peculiarities, but their relationship to the Protopt. 

 is traceable via Fun. armata and Protopt. cyaneum. The P. verticillata arose 

 from the P. bilaterata; at the base of their stem are the Scleroptilidse, which 

 may be regarded as a group, without calyces, parallel to the Protopt. and 

 as having taken origin from near Kophobel. From Scleropt., by reduction of 

 spicules, Calibel. has arisen. By spreading apart of the whorls the Chunel- 

 lidse are reached, including Amphiacme, in which there are well developed end- 

 polyps; a disappearance of the whorls in the lower part of the rachis and a 

 concentration of those in the upper part leads to the Umbellulidse. The authors 

 derive the P. penniformia from the Stachyptilidae, which differ essentially 

 from the Pennatulidse only in the absence of leaves. Nearly related to the 

 latter fam. are the Virgulariidse ; at the base of the stem of this family is Pa- 

 vonaria (with which Halipteris is merged) which is connected with the Stachypt. 

 In Acanthoptilum , which is nearly related to Pav., there begins the develop- 

 ment of the lateral clusters into leaves and the localisation on their under 

 side of the leaf-spicules. From Acanth. the authors trace the evolution of two 

 groups, one in which the number of polyps per leaf is fixed definitely from 

 the first (Stylatula, Virgularia}, and the other in which, throughout the growth 

 of the leaves, new polyps are added at the ventral side (Scytalium, Scytaliopsis). 

 The authors regard the Pteroeididse as a parallel group to the Pennatulidse, and 

 they attribute their great external similarity to convergence, for there is a 

 striking difference in their spicules, in the naked zooids of Pt. and the occur- 

 rence of specially well developed zooids in the ventral middle line of the 

 rachis. These characters point to the origin of Pter. from Stylatula. Further 



Zool. Jahresbericht. 1910. Coelenterata. h 



