Mailer's Arcldv fur Anatomie^ Physiologie, §"c. 467 



M. Alcide D'Orbigny. The species was discovered at Martinique 

 by M. Rang, and is named by its present describer H. Rangii. 



Mailers Archivfur Anatomie Physiologie, ^c 1837- Pfirts 1 and 2. 

 (Contained from Vol. i. p. 587.) 



This number contains a Description of Euchytrseus, a new genus 

 of Annelida, discovered by Dr Henle of Berlin. These animals 

 are found in situations similar to the common earthworm, generally 

 rolled together in pellets of damp soil, amongst which they are not 

 easily seen until they have been detached by dissolving it in water. 

 They are found in the greatest numbers in the inside of flower-pots, 

 on account of which the generic name Euchytraeus (from %iir^oe, a 

 vase,) has been bestowed upon them. They will live about four- 

 teen days immersed in water. In length they vary from two to six 

 lines. The head is pointed and conical and the tail truncated. 

 The body is formed of a series of rings, each being barrel-shaped, or 

 swelling out in the centre. The fifth or sixth nearest the head is 

 proportionally longer than the rest. The number of rings varies 

 greatly in individuals of different length. In twelve specimens, 

 they ranged betwen nineteen and sixty-one. They are covered ex- 

 ternally by an epidermis, beneath which is a muscular skin formed 

 of longitudinal and transverse filaments. The organs of generation 

 are always situate between the eleventh and twelfth rings, from 

 which it is inferred that the growth of the animal takes place either 

 by the addition of new rings, or by the subdivision of those already 

 existing beyond the twelfth. Only one species belonging to this 

 genus has hitherto been discovered, and from its colour the name 

 Euchytroen^ alhidus has been chosen for it. Like the common earth- 

 worm it moves by means of minute bristles, four groups of which 

 are attached to each ring, viz. two on the belly, and one on each 

 side. The average number of bristles on each side is three ; in the 

 earthworm the average is two, and several other points of difference 

 occur between them. In Euchytraeus they are straight and point- 

 ed, and they sometimes seem to be attached to each other by a mem- 

 brane resembling the web of a swimming bird. They take their 

 rise in the inner muscular skin before-mentioned. In the systema- 

 tic arrangement of the Annelidae, Euchytraeus occupies a place next 

 to Lumbricus, from the similarity of its form, its organs of locomo- 

 tion, and its internal structure. Lumbricus rivalis, described by 

 Fabricius in the Fauna Groenl. p. 278, seems to approach the nearest 

 to it, but his description is somewhat vague Remarks upon the 



VOL. II. NO. 11. I i 



b 



