Dr. R. Greeff on Autolytus prolifer. 173 



I cannot understand Dr. W. Thomson's habitat of the two 

 species of Venus's Flower-basket. He says, " The only known 

 specimen of H. speciosuni is that iigured by MM. Quoy & Gai- 

 mard in the ' Voyage de 1' Astrolabe,' and now in the Jardin 

 des Plantes. The specimen is labelled '■ Alcyoncellum corhicida^ 

 Val. Tir^ par 80 brasses de profondeur dans la rade de St. 

 Denis de Bourbon par M. Leschenault, 1819.' " If he will 

 turn to MM. Quoy and Gaimard's work, he will find those 

 authors state that their specimen was given to them by Mr. 

 Merkus, the Governor of the Moluccas. The same specimen 

 cannot have two habitats or be collected by two persons at dif- 

 ferent periods. Does not the label belong to the true Alcyon- 

 cellum corhicula'^ The label is of little importance if Alcyon- 

 cellum speciosum and A. corhicula are one species ! ! 



XXV.— Ow Autolytus prolifer. By Dr. R. Greeff *. 



[Plate VIII.] 



In the year 1850, Grubef established, under the name of 

 Autolytus^ a new genus of Annelids, previously regarded as 

 forming a species of Syllis. Autolytus, indeed, has characters 

 so definite and so different from those of Syllis, as is shown 

 by even a cm'sory comparison, that this separation must be 

 indicated as not only perfectly just, but actually necessary. 

 For the actual establishment of this idea, however, we are 

 indebted to A. Krohn, who, in his classical memoir " On 

 the Phenomena of Beproduction in Syllis jjrolifera and Auto- 

 lytus jpTolifer^'' first distinctly pointed out the distinctive cha- 

 racters of the two genera t. The interesting processes in the 

 reproduction of Syllis prolifer a and Autolytus prolifer (which, 

 however, as regards the latter, had certainly already been 

 carefully observed by Leuckart and Frey§) are elucidated in 

 this memoir from careful observation, both as regards what 

 they have in common and what is peculiar in each. With re- 

 gard to Autolytus prolifer, Krohn was able to confirm the 

 results already in part obtained by Leuckart and Frey, al- 

 though those observers still erroneously identified Autolytus 

 prolifer with Syllis prolifera, and therefore also could not 



* Translated by W. S. Dallas, F.L.S., from the ' Arcliiv fiir Natur- 

 geschiclite,' 1866, pp. 352-367. 



t Wiegmann's ArcMv,1850, p. 309, and Tamilien der Auneliden/ 1851, 

 p. 62. 



X Wiegmann's Arcliiv, 1852, p. 66. 



§ 'Beitriige zur Kenntniss wirbelloser Tliiere, &c.,' 1847, p. 91, pi. 2. 

 fig. 1. For the earlier observations of 0. F. Miiller, Milne-Edwards, 

 Quatrefages, Johnston, &c., consult the authors just cited. 



Ann. & Mag. N. Hist. Ser. 4. Vol.i. 13 



