12 F. A. SMITT, 



contracted on the sides below the middle." In my former papers '), I have shown the 

 developmental changes, how they are going out from the common origin of all the 

 Membraniporidans. Thus, in their lower stages, the species of this group scarcely will 

 be to distinguish from the preceding; but as the development goes on, through the 

 above-named character, they acqnire sush a peculiarity, as well can deserve its own 

 generical name. For that purpose the name Mollia, first proposed by Lamouroux 2 ), 

 here may be used, because it, by him, inclucled the first of our Floridan species, that 

 belongs to this group. But then, in the following, I must change the name of the 

 escharine genus, which I once 3 ) constituted with that name, while it included those 

 forms, which would best agree with the character given by Lamouroux. 



Of the above-named group, among the Pourtales' collections, we find two very 

 different species. 



Mollia patellaria 4 ) (Pl. II, fig. 72). 



It is one of the smaller bryozoa. The very regular, elliptical zooecia, in their 

 Mollia- (Diachoris-) growth, have a length of about 0,36 mm. From their sharp margin, 

 the finely granular, yellowish hyaline front side very steeply slopes down inwards to 

 a furrow, parallel with the circumference; inside of this it is gently swollen. The 

 subtrifoliate area has the proximal margin concave; its length as well as its greatest 

 breadth I have measured to about 0,1 mm. The sraoothly rounded ooecion developes 

 itself, in the usual manner, at the distal end of a zoeecion, very little raised above 

 the level of the front side of this. Sometimes, in the rows of the zocecia, we find 

 small features of the zooeeial form, which perhaps may be avicularia, althongh, in 

 their dried state, I have seen no true avicularian structure in them. 



This species, in very neat colonies growing on a Nullipora, is taken by Pour- 

 tales, at Florida, from a depth of 36 fathoms. In accordance with Busk, I have iden- 

 tified it with the mediterranean form; although the descriptions by Moll and Heller 

 do not give any surety as to the form of the zooeeial area. 



Mollia antiqua 5 ) (Pl. II, fig. 73). 



To the description and excellent figures of the Madeiran specimen, given by 

 Busk, I will only mention the difference, which perhaps will strike any one, in compa- 

 ring my figure with them. This difference, consisting in the more pointed distal end 

 of the zooecia, only depends on the more highly calcificated constitution of the figured 



] ) Krit. Fört., 1. c, pag. 388, 405 etc. 

 -) Pol. Cor. Flex., pag. 115. 



Since then a new geuus, Diachoris, with almost the same characters, has been constituted by Busk 



(Voy. Rattlesn., pag. 382; Brit. Mus. Cat., Polyz., pag. 53); but as the types of that genus seem to be 



Bugularidan species, it must be used within the limits of that family. 

 '■'■) Bidr. etc, Öfvers. Vet. Akad. Förh. 1867, Bih., pag. 14. 

 4 J Eschara patellaria, Moll, Eschara, p. 68, tab. IV, fig. 20. 



Diachoris simplex, Heller, Bryoz. Adr. Meeres, Verh. d. k. k. zool.-bot. Gesellsch. Wien, Bd. XVII 



(1867) p. 94 (p. 18 sep.), tab. I, fig. 4. 

 ') Membranipora antiqua, Busk, Zoophyt.. Quart. Journ. Micv. Se, vol. VI, pag. 262, pl. XX, figs. 1 and 2. 



