FLORIDAN BRYOZOA. 7 



and is now to be registered among the Floridan Bryözoa. Yet, the only specimen, 

 Pourtales has sent me, as found at a depth of 270 fathoms off Havana, was dead 

 when taken. As I can here offer very good figures of it (figs. 11 — 13), it will easily 

 be seen, that it presents all the charaeteristics of the above named species x ), only that 

 the back side (see fig. 13) has löst all its covering ectocyst, so that its striation is 

 gone away and the pores gape wider. 



These pores, which have caused Stoliczka, after D'Orbigny, to separate this spe- 

 cies from the Idmonece, I have sanetimes found 2 ) as abortive zooecia even on the ldm. 

 atlantica; and if it were only for them, I should not adopt the D'Orbigny'an genus 

 Orisina; but the ooecia (ovicells), described by Reuss and Hagenow, on the Crisina disticlia 

 and Cr. lichenoides offer a characteristic for the genus of greater signifieance. This 

 characteristic I have not seen myself, and it is very problematical, if the Crisina Hoi-li- 

 stetteriana will show it. This I can say, because what I described for Idmonea atlan- 

 tica and, after all analogy, declared to be its ooecia 3 ), that structure we find even here, 

 on the Crisina Hochstetteriana, although in a very reduced state. It is a punctated 

 tutnidness, along the front angle of the stem (see figs. 11 and 12), what Stoliczka 

 has named the »Vorderseite in der Mitte stumpfkantig». Now, after this single specimen, 

 I can-not give a scientific judgment, and it seems to me very probable, what Stoliczka 

 has reinarked, that the Crisina!, when b etter known, will show the same developmental 

 relation to the Idmonece, as Hornera shows to Filisparsa. Then, in the Crisina Hoch- 

 stetteriana, we should see one of the first links in such a divergent series; and, indeed, 

 it coraes very near to Idmonea atlantica. 



All these Idmonece as well as the Crisina? are characterized by the greater deve- 

 lopment of the median zooecia, whilst the lateral ones are to be more or less reduced. 

 Another group of this family shows the opposite relation in this respect, and, at the 

 same tiine, of course, the median line of the front side of the stem becomes more and 

 more rounded. In my first treatise on these animals, I had not sufficiently attended 

 to the importance of this point, and there can be no doubt, that these species hold a 

 position very near to Idmonea serpens; but, as Milne Edwards has already pointed 

 ont 4 ), they show a tendency towards the configuration of the Hornerce. Among the 

 species that have been described and, probably, ought to be referred to this group, the 

 ldm. transversa (Lam.) M. Edw. °), ldm. Milneana, D'Orb. 6 ), ldm. Californica, Gabb 

 et Horn '), and ldm. Giebeliana, Stol. 8 ), seem to have almost the same right to be 

 identified with that brought up by Pourtales from 19 — 60 fathoms at Florida and off 



') Nov. Exp., Geol. Th, Bd. 1, p. 113, tab. XVIII, fig. 3. 

 -) Krit. Fört. in Öfvers. Vet.-Akad. Förh. 1866, pag. 441. 



3 ) Krit. Fört., 1. c, pag. 442. 



4 ) Aim. d. Se. nat. 2:de ser., torae IX, pag. 218. 



5 ) 1. c. pag. 217, tab. IX fig. 3 et 3, a. 



6 ) Voy. d. VAmér. mer., Polyp., pag. 20, tab. IX fig. 17 — 21. 



') Monogr. Foss. Polyz. See. Tert. Form. N. Amer., Journ. Acad. Nat. Se. Philadelphia, N. ser., Vol. V, pag. 



168. tab. XXI. fig. 56. 

 8 ) Foss. Bryoz. Orak. B. in Auckland, Nov. Exp., Geol. Th., Bd. I, Abtli. 2, pag. 115, tab. XVIII fig. 4—6 



