REPORT ON THE ALCYONARIA. Ivii 



23. Muricea, Auct. emend. Verrill (as subgen.), Trans. Connect. Acad., W. i. p. 450, 

 1869. 



The colony is l)ranched, with a thick coenenchyma and terminally bilobed polyp 

 calyces markedly projecting. In the polyps when retracted the dorsal half of the calyx 

 projects as a lip. The tentacular operculum is drawn into the calyx. The spicules are 

 either warty spicules, which are usually short and thick, or they sometimes approximate 

 to the club-shaped form. Besides these, long spiny spicules usually occur in the deeper 

 layers. 



Family IX. Plexaurid^. 



Plexauridx, Gray, Ann. and Mag. Nat. Hist., ser. 3, vol. iv. p. 444, 1859. 

 Ewiiceidx, Kolliker, Icones histiologies, pt. ii. p. 137, 1859. 

 Plexauridx, Verrill, Trans. Connect. Acad., vol. i. p. 413, 1869. 

 Plexauridx, Klunzinger, Korallthiere des rothen Meeres, pt. i. p. 51, 1877. 



The polyp colony is usually branched and upright. The axis is horny, or horny and 

 calcareous, especially at the base. The coenenchyma is thick. The polyps occur over 

 the whole circumference of the coenenchyma. The anterior tentacular and oesophageal 

 portions of the polyps are retractile into a calyx region, forming wart-like protuberances, 

 or they are completely retractile into the coenenchyma. Thus, in many instances the 

 apertures of the polyps appear as openings or simple pores in the coenenchyma. The 

 canalicular system consists of small reticulate canals, radiating from the polyp cavities, 

 and opening finally into the longitudinal canals, which latter are arranged symmetrically 

 around the axis. The spicules are usually large, of variable form ; the cortical layer 

 mostly' consists of a layer of clubs, beneath which spindle-shaped spicules are found. 

 The tentacles of the polyps are at their bases provided with .spindle-shaped spicules. 



Verrill's^ diagnosis of this family is here reproduced; he has most tersely summed u}) 

 the characteristics of the group. The genus Eunicella was first referred by Verrill to 

 the Gorgonidse, but was afterwards " rightly placed in this family. A divergent type is, 

 however, represented by Eunicella albicans, Verrill, in which the flat axis recalls the 

 structure of many Gorgonidse. 



The Plexauridse are most nearly related to the Muriceidse, Eunicea is closely related 

 to Muricea, while on the other hand Eunicella leads on to the Gorgonidse. 



1. Eunicea, Lamouroux. 



2. Plexaura, Lamouroux. 

 3 Plexauroides, n. gen. 

 4. Plexaurella, Kolliker. 



5. Pseudoplexaura, n. gen. 



6. Euplexaura, Verrill. 



7. Psammogorgia, Verrill. 



8. Eunicella, VerriU. 



9. Platygorgia, Studer. 



1 Notes on Radiata, Trans. Connect. Acad., vol. i. p. 41.3. ^ jiraer. Journ. Sci. and Arts., vol. .xlviii., 1869. 



