22 Coelenterata. 



well placed in either of these genera. M. hartii occurs in the form of a typical 

 Mussa and in the form of a Symphyllia, while Meandra conferta is intermediate 

 in all its characters between this genus and Favia and shows the close rela- 

 tions and common origin of these two genera. Favia leptophylla closely re- 

 sembles an Orbieella, thus showing the close relationship of two genera, typical 

 of two groups, often considered as of sub-family or even family rank. Mean- 

 drina (Pectinia) braziliensis is an ancestral form of its genus, as it retains 

 throughout life the simple lobulated condition of growth characteristic of the 

 young of the much larger and more complex forms of the West Indies. Very 

 few of the W. Indian corals are strictly identical with those of the Brazilian 

 reefs (the huge volume of fresh water discharged by the Amazon forms a 

 barrier between these two areas) others are absent. The Brazilian coral fauna 

 is however much more nearly related to the W. Indian than to any other fauna. 

 A revised list of Brazilian reef corals is given in which are described Mussa 

 (Symphyllia) 1 n., Agaricia 1 n. var., Porites 1 n. var. 



B. Alcyonaria. 



See Kishinouye, Kukenthal and Whitfield. 



Hicksonl 1 ) describes Xenia 1, Telesto 2 (1 n.), Spongodes, Nephthya 1, Para- 

 spongodes 1, Chironephthya 1 n., Siphonogorgia 1, Solenocaulon 2 (1 n.) and 

 Melitodes from the Maldives. The species of Spongodes have a very wide geo- 

 graphical range in tropical waters, are extremely variable, and the characters 

 upon which new species have been founded in recent years are untrustworthy; 

 possibly there is only oue true species. Wright and Studer state that Chiro- 

 nephthya is essentially distinguished from Siphonogorgia by the polyps occurring 

 along the entire course of the branches and being less retractile, but according 

 to the author these characters do not serve to distinguish the genera. The 

 tubular character of Solenocaulon is probably of the nature of a "gall" pro- 

 duced by a Crustacean (Alpheus] and the degree to which it affects the secon- 

 dary and tertiary branches depends, not on any inherent specific character of 

 the ., but upon the number or activity of the symbiotic Crustacea. The 

 smoothness, absence of polyps and pale colour of the grooves on the side of 

 the now tubular terminal branchlets suggests that these Crustacea are in the 

 habit of running along them in search of food and of retreating to the tubular 

 parts for protection. 



Kassianow has investigated the nervous system of Alcyonium digitatum 

 and palmatum, by maceration and by sections. It consists chiefly of a rich 

 plexus distributed over the oral disc, the oral face of the tentacles and the upper 

 part of the stomodseuin. It is especially strongly developed in the oral disc and 

 upper part of the stomodseum along the lines of attachment of the mesenteries. 

 Consequently there are 8 tracts which lie in the oral disc and in which the fibres 

 run principally outwards from the mouth. At the edge of the oral disc most 

 of the fibres ascend the tentacles and spread out in a rich plexus over their 

 longitudinal ectodermic muscles. At the sides of the tentacles, where the pin- 

 nules are inserted, there is a richer nervous supply corresponding to the greater 

 development of the muscles in these parts. The nerve fibres are generally most 

 closely associated with the muscles, especially the ectodermic muscles. In the 

 body wall and coanenchym the nervous system is very difficult to demonstrate. 

 The nerve tracts above mentioned are formed of processes of ganglion and 

 sense cells. The latter are especially abundant on the oral face of the ten- 

 tacles and in the stomodseal epithelium around the siphonoglyph. Ganglion 



