ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 891 



heart, and is connected with the ventral vessel. The heart of BonelUa 

 (Lacaze-Duthiers) is a sac-like expansion of the ventral vessel and is 

 found about the middle of the cavity ; at this point there is in 

 Hamingia a vascular plexus uniting the dorsal and ventral vessels. 

 The nervous system, again, has the pharyngeal ring more typically 

 arranged than in BonelUa. Unlike this form the new genus presents 

 a bisymmetrical arrangement of the uteri. Saccosoma vitreum n. g. 

 et sp. is also an asetous form, which, while it differs in some important 

 points from the other Bonellidae, is personally most remarkable on 

 account of the extreme tenuity of its intestinal walls ; these form 

 merely a " gauzy pellicle," and are so difficult to detect that, for long 

 the authors were in doubt as to whether there was any intestine at all, 

 " conceiving the whole posterior portion of the animal to constitute a 

 receptacle for the faeces." The authors seem to be in great doubt as 

 to whether this form should not be the type of a new family, but un- 

 fortunately a single specimen only was found. The only new family 

 here defined is that of the Epithetosomatidae {EpitJietosoma norvegicum 

 n. g. et sp.). Just behind the base of the proboscis this creature has 

 a cleft or fissure, the bottom of which appears to be pierced with a 

 number of minute apertures ; on the inner surface of the skin, and 

 extending along either side of the anterior end of the body and inside 

 the fissure is a row of rounded apertures (four on each side) ; a kind 

 of sphincter is formed around the orifices which lead to the bottom of 

 the fissure ; at the last point we find a kind of respiratory apparatus, 

 through which the sea water is enabled to commimicate with the peri- 

 visceral cavity, " for the labia of the fissure can evidently expand and 

 contract for the admission and expulsion of the circulating fluid." 

 Only two specimens, both in a bad state of preservation, were obtained, 

 and the authors' account of some of the other organs is consequently 

 imperfect. The presence of the respiratory apparatus just described 

 is, however, a sufficient reason for the establishment of a new family, 

 as it is an arrangement to which there is nothing analogous in other 

 Gephyrea. 



The authors conclude by remarking that, in their opinion, the 

 present arrangement of the Gephyrea into the two orders G. inermia 

 and G. armata is hardly satisfactory ; three genera, here described, are 

 without setfe, but they are nevertheless, on account of their anatomical 

 structure, referred to the armed order ; whereas, if the systematic 

 classification had been strictly followed, they would have been placed 

 among forms with which they have comparatively little in common. 



Hamingia glacialis.* — In describing this new asetal Echiurid, Dr. 

 E. Horst points out that the homologue of the secondary gut, first 

 noticed by Spengel in Ecliiurus, is represented by a canal developed 

 from the wall of the exterior, and connected posteriorly with the 

 hinder portion of the intestine. Like Lankester,| the author is 

 unable to accept Greef's account of the structure and function of the 

 anal tubes. 



* Zool. Anzeig., iv. (18S1) pp. 44S--50. 

 t See this Journal, ante, p. 738. 



