280 rOLYZOA INFUNDIBULATA. 



5. Alecto,"^' Lamouroux. 



Character. — Polypidom calcareous^ creeping, entirely ad- 

 nate, irregularly branched^ formed of horizontal tubular cells 

 produced in a linear series, the upper portion of the cell erect 

 tcith a circular entire aperture. 



1. A. GRANULATA, cclls uniscrial, their parietes granulous. 

 W. Thompson. 



Plate XLIX. Fig. 1, 2. 



Alecto granulata, M. Edwards Mem. p. 1 3, pi. ] 6, fig. 3, 3. — Tubulipora trahens, 

 Couch Zooph. Cornw. 45 : Corn. Faun. iii. 105, pi. 19, fig. 5. (not good). 



Hah. — On the inner surface of old bivalve shells, not uncommon ; 

 more rarely on stones, and on the outer surface of shells. It is 

 apparently a deep-water species. 



Polypidom confervoid, slender, more or less branched, entirely 

 adherent, branches irregular, usually patent, sometimes anastomosing, 

 consisting of a single series of tubular cells, leaning almost imper- 

 ceptibly to opposite sides, the upper half becoming suddenly erect 

 and free, with a circular even aperture. The whole polypidom is 

 frosted or minutely granulous, and the walls are vitreous, except in 

 dead specimens, which sometimes become opake-white. 



The base or adhering part of the polypidom is very slightly dilated. 

 The horizontal portion of the cell is enlarged almost imperceptibly 

 upwards until where the upper portion rises abrupt, and this is 

 rather narrower and quite cylindrical. The mode of ramification is 

 very various. Specimens of this kind often occur : there is a long 

 line of single tubes, with a branch or two of the same character, when 

 a portion succeeds with two cells opening side by side, then perhaps 

 three in a row, and the branch terminates in a dilated end. Some- 

 times the cells are scattered and almost disjunct, forming a rude 

 circular patch ; but even in this form it is known by the peculiar 

 character of the tubes, half horizontal and half erect. 



* Alecto, one of the Furies, having serpents round her head instead of hair. Vir- 

 gil (7En. vii. 327, &c.,) thus describes her : — 



" Odit et ipse pater Pluton, odere sorores 

 TartaresB monstrum : tot sese vertit in ora, 

 Turn saivffi facies, tot pullulat atra colubris." 



