4 F. A. SMITT, 



ectocyst, nearest in the same way as do the Cupularia and several forras of the Escha- 

 rine type '). 



It is through this mode of calcification, that the Farcimia cereus acquires such 

 a different appearance after the condition of the specimens. When unworn (fig. 55), 

 it shows the yellow, shining surface smooth, with the markings only of the regular 

 elliptical area? of the zooecia in four alternating rows, the distal end of the one area 

 intruding a little between the proximal ends of its two nearest heigher neighbours, 

 with a rounded aviculariura at each side. The avicularia then show nearly the same 

 form and position as in Nellia oculata, with the difference only that they are single 

 here in each place and stånd a little lower. The most important difference between 

 the two genera in this state is to be seen in the opercular apparatus at the distal end 

 of the apertural area of the zooecia. In the worn condition (fig. 56), however, the 

 Farcimia cereus presents a totally different appearance. Then the avicularia no more 

 can be seen, the apertural areas of the zooecia, to the greatest part of their extent, 

 are closed by a concave calcareous lamina, and the interstices between the areas are 

 cancellated by calcareous ridges, very much resembling what is to be seen on the My- 

 riozoa The form of the open space, left by the calcareous lamina in the apertural 

 area, is very constant, the distal end of it answering to the form of the operculum. 

 As to the size of the zooecia, I have measured the length of one area to be very 

 nearly = 0,5 mm. 



According to Pourtales, this species is rather abundant in 270 fathoms off Ha- 

 vana; I have only seen a few broken specimens from that locality. 



Of the genas Cellaria, the Floridan fauna contains a variety of the same type as 

 the oldknown Cellaria fistulösa. This varietj' very well deserves its own name, as it 

 has already received it by Busk, 



Cellaria tenuirostris 2 ) (Pl. I, figs. 57 — 59); 



though it will be seen, that it is so closely connected with the typical form from the old 

 continent, that we must suppose them to have the same origin. The most important 

 difference, as already was remarked by Busk, is to be expressed by the form of the avicu- 

 laria (figg. 57 and 58), what organs, on the Cellaria tenuirostris, replace a zooecion, 

 retaining the typical form of this, but the opercular apparatus is transformed to a 

 pointed, prominent rostrum, with a narrow, produced, pointed mandible. Another dif- 

 ference consists in the mode of connexion between the branches of the stem, accom- 

 plished by a knöt of intricated radical tubes (fig. 57), what connexion I never have 

 seen on the typical Cellaria, fistulösa. The ooecia (ovicells, fig. 59) of the C. tenuirostris 

 develop themselves in the same manner as on C. fistulösa, though they are not so 

 much immersed; and very often they present a feeble longitudinal ridge över their 

 front-side. Their opening is in the beginning round and broad, but after their full 



1 ) The Irue sionification of this mode of calcification, I can not study on died and dried specimens. Further 

 down, in a yet more complicated form, we shall see it upon a Microporidan species. 



2 ) Salicornaria tenuirostris, Busk, Brit. Mus. Cat. Polyz., p. 17, tab. LXIII, fig. 4. 



