THE BRANCHING -SYSTEMS OF THE ALCYONACEA. 



525 



fused into a single bundle for a considerable length, but eventually first one and then 

 another raceme emerges from the bundle as a branch, and by continued subdivision of 

 their axes and the emergence of bundles of these as secondary and tertiary branches a 

 ramifying system is formed, the ultimate axes finally emerging on the twigs as the 

 anthocodiae of the zooids. 



a.b. c.d. 



Diagram of the brauchiiig-systeni of a Nephlhyid. — The authodete is represunted as consisting of four chief members 

 a, b, c, d, each of which branches in one plane on tlie racemose system. The anthosteles of the lateral 

 members run parallel to those of the chief members, and aie organically fused with them and with each other 

 throughout the greater part of their length, a', 6', c', rf'. Terminal anthocodiic of the chief members. 

 a'. Terminal anthooodia of a lateral member of the second order. «■", a*. Anthocodi* of third and fourth 

 orders. It should bo noted that the branching-system of the anthodete as a whole, which in this case is a 

 dichotomy, does not corresi)oud with that of its component members. 



In this case the primary axis is represented as growing at a rate equal to the secondary 

 and other axes, but there are cases in which the primary axis is arrested in growth and 

 the other axes grow past it and alone pass into tlie branches. In other words, the 

 primary zooids may undergo cymose subdivision, and in this ease their anthocodiiB 

 degenerate and the apodete is formed only by the secondary or lower orders of zooids. 

 None the less the longitudinal canals of the stem and large branches are the anthosteles 

 of the primary zooids. 



The racemose mode of subdivision of the primary zooids is well illustrated in the genus 

 Iismnalia, Gray, a member of the family Nephthyidcs and the subfamily Slphonogorghics. 

 The specimen figured in PI. 40. fig. 4 formed part of a collection of Anthozoa collected by 

 the late Dr. Gulliver at Zanzibar, and presented by him to the Oxford University Museum. 

 It is clearly identical with Verrill's AmmotUea nitida *, also from Zanzibar, but it does 



• Bull. Mus. Comp. Zool. Harvard, vol. i. 1864, p. 39. 



