110 



ESSAY ON CLASSIFICATION. 



different genera of the family. Nothing is as yet known of 

 the development of Brachiopods. The Gasteropoda 1 ex- 



1 CARFS, (C. G.,) Von den aussern 

 Lebensbedingungen der weiss- und 

 kaltbliitigen Thiere ; Leipzig, 1824, 

 4to., fig. PEEVOST, (J. L.,) De la 

 gen6ration chez le Lymnee, Mem. Soc. 

 Phys., Geneve, vol. 5, p. 119. SARS, 

 (M.,) Zur Entwickelungsgeschichte 

 der Mollusken und Zoophyten ; 

 Wiegm. Arch., 1837, 1., p. 402; 1840, 1, 

 p. 196. Zusatze zu der von mir gege- 

 benen Dartstellung der Entwickelung 

 der Nudibranchien ; Wiegm. Arch., 



1845, I, p. 4. QUATREFAGES (ARM. 



DE,) Memoire sur 1'Einbryogenie des 

 Planorbes et des Lyrnnees; Ann. Sc. 

 Nat.,2de ser., vol. 2, p. 107. VAN BE- 

 NEDEN, (P. J.,) Recherches sur le de- 

 veloppernent des Aplysies ; Ann. Sc. 

 Nat., 2de ser., vol. 15, p. 123. VAN 

 BENEDEN, (P. J.,) et WINDISCHMAN, 

 (On.,) Recherches sur FEmbryogenie 

 des Limaces, Mem. ; Ac. Brux., 1841. 

 JACQUEMIN, (En.,) Sur le deve- 

 loppement des Planorbes ; Ann. Sc. 

 Nat., vol. 5, p. 117 ; Nov. Act. Nat. 

 Cur., vol. 18. DUMORTIER, (B. C.,) 

 Memoire sur les evolutions de I'em- 

 bryon dans les Mollusques Gastero- 

 podes, Mem. ; Ac. Brux., 1836, vol. 

 10. LAURENT, (J. L. M.,) Observa- 

 tions sur le developpernent de 1'ccuf 

 des Limaces ; Ann. Sc. Nat., vol. 4, 

 p. 248. POUCHET, (P. A.,) Sur le de- 

 veloppement de 1'embryon des Lym- 

 nees ; Ann. Sc. Nat., 2de ser., vol. 10, 

 p. 63. VOGT, (C.,) Recherches sur 

 1'Embryologie de I'Actseon ; Ann. Sc. 

 Nat. 3e ser., 1846, vol. 6, p. 5. 

 Beitrag zur Entwickelungsgeschichte 

 eines Cephalophoren ; Zeitsch. f. wiss. 

 Zool., 1855, vol. 7, p. 162. SCHULTZE, 

 (M.,) Ueber die Entwickelung des 

 Tergipes lacinulatus; Wiegm. Arch., 

 1849, I., p. 268. WARNECK, (N. A.,) 

 Ueber die Bildung und Entwickelung 

 des Embryo bei Gasteropoden, Bull. 

 Soc. Imp. ; Moscou, 1850, vol. 23, I., 

 p. 90. SCHMIDT, (0.,) Ueber die Eut- 

 wickelung von Limax agrestis, Miil- 

 ler's Arch., 1851, p. 278. LEYDIG, 

 (F.,) Ueber Paludina vivipara^ ein 



Beitrag zur nahern Kenntniss dieses 

 Thieres in embryologischer,anatomis- 

 cher und histologischer Beziehung, 

 Zeitsch. f. wiss. Zool., 1850, vol. 2, p. 

 125. KOLLIKER, (A.,) q. a., Zeitsch, 

 f. wiss. Zool., vol. 4, p. 333 and 369. 

 MULLER, (J.,) Ueber verschiedene 

 Formen von Seethieren, Mviller's 

 Arch., 1854, p. 69. Ueber Synapta 

 digitata und iiber die Erzeugung von 

 Schnecken in Holothurien ; Berlin, 



1852, 4to. fig. The remarkable case 

 described in this paper admits of an 

 explanation which Muller has not 

 considered. It is known that fishes 

 (Ophidium) penetrate into the cavity 

 of the body of Holothurisa, through 

 its posterior opening. (DE BOSSET, 

 Notice, etc., Mem. Soc. Sc. Nat., 

 Neuch., 1839, vol. 2, 4to. I have 

 observed the fact myself in Florida.) 

 The similarity of Entoconcha mira- 

 bilis with the embryonic shell of 

 various species of Littorinae, such as 

 Lacuna vincta, the development of 

 which I had an opportunity of study- 

 ing, suggests the possibility, that 

 some species of this family, of which 

 there are many very small ones, se- 

 lect the Synapta as their breeding 

 place, and leave it after depositing 

 their eggs, which may become con- 

 nected with the Synapta, as our 

 Mistletoe or the Orobanche and many 

 other parasitic plants with the plants 

 upon which they grow. GEGEN- 

 BAUER, (C.,) Beitriige zur Entwickel- 

 ungsgeschichte der Landgasteropo- 

 den, Zeitsch, f. wiss. Zool., 1852, vol. 

 3, p. 371. Untersuchungen iiber 

 Pteropoden und Heteropoden ; Leip- 

 zig, 1855, 1 vol., 4to. fig. KOREN, 

 (J.,) und DANIELSSEN, (D. C.,) Bitrag 

 til Pectinibranchiernes Udviklings- 

 historie, Bergen, 1851, 4to. ; French 

 Sc. Nat., 1852, vol. 18, p. 257, and 



1853, vol. 19, p. 89 ; also Germ, in 

 Wiegm. Arch., 1853, p. 173 ; see also 

 Fauna littoralis Norvegias 2de livr. 

 NORDMANN, (AL. V.,) Versuch einer 

 Monographic von Tergipes Edwardsii; 



