212 
MOLLUSCOIDA. 
tinguished j one histological element of the parent thus giving rise to 
all the elements of the descendant. These observations contradict 
Hackel’s theory that in all Metazoa the ectoderm is genetically identical, 
as is likewise the endoderm. Z. wiss. Zool. xxv. suppl. vol. pp. 343-361, 
and pp. 390-402, pis. xxv. & xxvi. 
Chilostomata. 
Cellepora tridens^ sp. n., Kirchenpauer, Ber. Unters. Pommerania, 
p. 188, woodcut ; Bukenf jord, Norway, 106 fathoms. 
Hippothoa divaricata, var. n. carinata, Norman, Ann. N. H. (4) xv. 
p. 171, pi. xii. figs. 4-7, Falmouth and Lisbon cable. 
Flustra. The species of this genus occurring in the Northern seas 
are discussed by Kirchenpauer, Ber. Unters. Pommerania, pp. 175-178, 
and 184 & 185, including F. dichotoma, sp. n.,p. 177, Belt, 10-16 fathoms. 
Caberea ellisi (Flem., as Flustra) = Cellularia hoolceri (Johnst.). 
Critical notes on this, and on Caberea and Canda (Lamx., nec Busk) ; id. 
1. c. p. 182. 
Cyclostomata. - . 
Idmonea, Discoporella^ Crisia, and Hornerq,. Notes on their larval 
stages by Barrois ; 0, R. Ixxxi. p. 1134 ; R. Z. (3) iii. p. Ixvii. 
Ctenostomata. 
Vesicularia ^nd Alcyonidium. Note on their larval stages by Barrois ; 
0. R. 1. c. pp. 288 & 443 ; R. Z. (3) iii. pp. li. & liv. 
Alcyonidium gelatinosum (Pall.) observed at Buenos Ayres; Weyen- 
bergh. Period. Zool. Argent, i. pt. xi. [1874]. 
Lopuopoda. 
Alcyonella fungosa: see Nitsche, swprd, p. 211. Notes on the larval 
stage by Barrois ; C. R. Ixxxi. p. 904 ; R. Z. (3) iii. p. Ixiii. 
EndDpjroota. 
. Loxosoma hefersteini (Clap.), living on Zoobotryon^ agrees in structure 
very much with Pedicellina, but is solitary ; its propagation by budding 
is minutely described, the buds are situated alternately on the right and 
left sides, and are formed only by the ectoderm of the parent, but very 
soon show distinctly ectoderm and endoderm, affording an instance of 
the direct origin of endoderm from ectoderm. The young animal has 
only 10, the adult 14 tentacles. L. neapolitanum (Kowalewsky) much 
resembles this young state. Nitsche, Z. wiss. Zool. xxv. pp. 451-456. 
Loxosoma differs from Pedicellina only by being solitary (as Ascidia 
from Clavelina)^ every individual being therefore provided with a pedal 
gland, and by producing only a few eggs, the breeding pouch of PedU 
cellina being therefore wanting ; Schmidt’s view, that the lateral off- 
spring comes from eggs, is opposed. Id. op. cit. suppl. vol. pp. 361-389. 
Pedicellina. Notes on the larval stage by Barrois ; C. R. Ixxxi. p. 904; 
R. Z. (3) iii. p. Ixiii. 
