350 POLYZOA INFUNDIBULATA. 



sura osculi amplitudinem fere totius cellulse habet, et cilice 8 vel 

 10 ab utroque latere conniventes aperturam fere claudunt." 



I am inclined to believe that Flustra lineata is not a species but a 

 state of a Lepralia, sometimes of L. nitida, sometimes of L. ciliata, 

 or of annulata, and perhaps of some others. The objection to this 

 conclusion is that it is found abundantly in situations where all 

 these LepralijB are rare. Mr. Peach is decidedly of opinion that it is 

 a good species. " I have found it," he writes me, " from its earliest 

 state to old age and it invariably presents the same appearance as 

 other corallines do in their progress through their various stages of 

 development : — first thin pearly transparent, and then thickening 

 and more opaque until old, — then the ribs thickened and more dull. 

 It is more ridged in the centre, and the ribs do not touch, as in 

 Lepralia nitida. In fact each may be clearly observed distinct in 

 every stage." 



What have been described under the names oi Flustra distans (^A. 

 Hassall in Ann. Nat. Hist. vii. 369), and specimens which I have 

 named to some of my correspondents Fhistra fallax, (Plate LVII, 

 Figs. 11 & 12.) are merely states of Lepralia? and Membraniporse. 

 It is often difficult, however, to refer the imperfect specimens to 

 their true species. 



Flustra arenosa, Ellis and Soland. Zooph. 17. Stew. Elem. ii. 437. Bosc Vers? 

 iii. 142. — Millepora arenosa anglica, Rail Syn. i. 31. — English Sandy Millepore, 

 Ellis Corall. 74, no. 5, pi. 25, fig. e. — Eschara lutosa, Pall. Elench. 37. — Alcyo- 

 nium arenosum, Turt. ,Gmel. iv. 564. Tin-t. Brit. Faun. 207. — According to Mr. 

 Boys this " is undoubtedly the nidus of some marine animal, as I have found the 

 cells entire, with eggs in each." Lin. Trans, v. 231. Mr. J. Hogg has proved 

 that it is the nidus of Nerita monilifera. Lin. Trans, xiv. 318, &c. 



17. EscHAEA,* Ray. 



Character. — Polypidom memhrano-calcareous^ iiifiexihle^ 

 hrittle^ expanding in the form of foUaceous porous lamellee., 

 variously/ folded and anastomosing, and consisting of two layers 

 of opposite cells: Cells immersed, coalescent, horizontal to the 

 plane of axis, opening on hoth surfaces in quincuncial pores 

 protected with an operculum. 



1. E. foliacea, plates foUaceous, winding, uniting irregu- 



* E(Txa|0«, the scar from a burn. 



