296 Z. ASCIDIOIDA. Retepora. 



often blackish and emitting fibrous radicals ; the intervening spaces 

 long, cylindrical, frequently swollen near the upper end, covered all 

 round with lozenge-shaped immersed cells, disposed in quincunx, and 

 radiating from the centre. 



In a weak mixture of muriatic acid and water, the calcareous por- 

 tion of the polypidom is entirely removed without any other altera- 

 tion in its form and structure, and we learn from the experiment that 

 the joints are connected together by capillary corneous tubes, equal 

 in number to the series of cells. These tubes cannot be traced 

 through the immediate spaces, but from the circumstance of their 

 being hollow, it seems not unreasonable to infer that they may na- 

 turally be filled with an irritable pulp, and be the medium of com- 

 munication between the cells and polypes of the different interspaces. 

 The branches are not tubulous or fistular, as Blainville has properly 

 remarked ; whence the impropriety of the Linnaean trivial name, the 

 retention of which only tends to the perpetuation of error. 



Under this species Pallas has the following interesting observation : 

 " Celerrime hanc Celhdariam crescere, saltem celerius embryone 

 Squall, docuerunt ova Squali Promontorio merid. Africes allata, in 

 quibus pl^ntulas plures semipollicares observavi, quanquam foetum 

 adhuc immaturum continerent." 



38. Retepora,* Lamarck. 

 Character. — Coral foliaceous^ stony, fragile, netted: cells 

 opening only on the upper or inner side, short and not prominent, 

 — Polypes ascidian. 



1. R. RETICVI.ATA, polypidom latticed, ivavy and convolute, the 

 upper side warty and very porous. Rev. William Borlasse. 



Millepora retepora, Borl. Cornw. 240, pi. 24, fig. 8 Millepora reticu- 

 lata, Lin. Syst. 1284. Fabric. Faun. Groenl. 433. JEllis and Soland. 

 Zoopb. 138 M. frondipora, Pall. Elench. 241 Retepora reti- 

 culata. Lam. Anim. s. Vert. ii. 182. 2de edit. ii. 273. Bisso, L'Eiirop. 



Merid. v. 343. Flem. Brit- Anim. 531. Stark, Elem. ii. 435 Re- 



tepore reticulee, Blainv. Actinolog. 633 Frondipore reticule. Ibid. 



406, pi. 69, fig. 1. 



Hab. Deep water, rare. Cornwall, Borlasse. 



" Expanding to the extent of 2 or 3 inches ; more or less cup- 

 shaped, waved, uniting ; the lobes are oval, regular, the intervening 

 spaces supporting two or three pores in oblique rows. This species 



" From Rete and to^oc, i. e. a " a porous net-work." 



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