QBPHYREA, ANNULATA. Vevm, 9 
rative ducts do not seem to be modified segmental organs. There are 
four natural orders of the Annelides : (1) Hirudinea^ (2) Oligochoeta, 
(3) Polychceta, (4) Gephyrea. The two former are derived from the 
Discodriliday and the two latter from Sternaspis ; the common ancestor 
of all is to be found in the Turhellaria. The larvas of Chcetopoda and 
Gephyrea are formed on the same type. 
Rietsch’s (46) papers are preliminary to a complete monograph. 
Andreas (41) describes the tegumentary glands of Sipunculus nudus 2 i.% 
being bi- or multi-cellular ; the large ppace connected with the ventral 
nerve-cord is an essential part of the same, and is not a blood-vessel. 
Sluiter (47) was usually able to find in fresh forms that there was an 
opening into the coelom just beside the posterior end of the brown tube ; in 
only one case was the orifice anterior. In forms in which the longitudinal 
musculature was not differentiated, no internal orifice could be made out. 
There appears to be an essential resemblance between the male and female 
organs. 
Andreae (41), like Greef [see Zool. Rec. xvii. Verm. p. 9], divides the 
Gephyrea into the Echiurida and Sipunculida ; on the other hand, 
Danielssen & Keren (42) do not regard as satisfactory the division of 
the order into G. armata and G. inermia ; they refer to the former three 
asetal genera, which agree with the G. armata in all the essential points 
of their anatomy. 
Echiurm unicinctuSy sp. n., Drasche (43). 
Hamingia glacialiSy sp. n., Horst (44). 
Aspidosiphon fuscuSy sp. n., Sluiter (see Zool. Anz. iv. p. 444). 
ANNULATA. 
60. Darwin, C. The Formation of Vegetable Mould through the Action 
of Worms, with observations on their habits. London : 1881, 8vo, 
326 pp. 
On part of this subject see M. Braun, SB. Ges. Dorp.vi.i. pp. 186-188. 
51. Eisig, H. tiber das Vorkommen eines schwimmblasenahnlichen 
Organs bei Anneliden. MT. z. Stat. Neap. ii. pp. 255-301, pis. 
xii.-xiv. 
52. Horst, R. Sur la fecundation et le developpement de 1’ Hermella 
alveolata. Bull. Sci. Nord. iv. pp. 1-4 ; see also Yersl. Ak. Arast. 
(2) xvi. pp. 207-214, 1 pi. 
63. . Die Anneliden gesammelt wahrend der Fahrten des “ Willem 
Barents.” Niedorl. Arch. Zool. Suppl. i. 1, pp. 1-26, 1 pi. 
54. . Bijdrage tot de Kennis der Anneliden van onzoKust. Tijdschr. 
Nederl. Dierk. Yer. 1881, pp. 120-130, pi. ii. {Arenicola piscatorum). 
55. Mau, W. Ueber Scoloplos armiger, O. F. Muller. Beitrag zur 
Kenntniss der Anatomie und Histologie der Anneliden. Z. wiss. 
Zool. xxxvi. pp. 389-432, pis. xxvi. & xxvii. 
