2 THE VOYAGE OF H.M.S. CHALLENGER. 



from the Forth near Inchkeith. This observer, besides giving a faithful account of the 

 external appearance of the animals, described more or less completely the integu- 

 mentary, muscular, vascular, and alimentarjr systems, as will be more particularly 

 alluded to under each of these heads. 



Next year Professor AUman ' figured and described an example received from the 

 former author. His account of the structure corresponds generally with Dr. Wright's. 

 Moreover, while pointing out the affinities of Pkoronis in certain aspects with the 

 Polyzoa, he was inclined to view it as Annelidan (Gephyrean) in its relationships. 



Dr. T. S. Cobbold in 1857" procured in the Forth, near Portobello, a species of 

 Actinotrocha (the larva of Phoronis, compare p. 22). This he seems at first to have 

 associated with the Polyzoa, from its prominent cephalic lobe (his epistome) and the 

 lophophoi'e, though certain structural objections were pointed out by Professor AUman. 

 The late Dr. Carpenter also, who had found Actinotrocha abundantly off the Isle of 

 Arran, drew the author's attention to J. MuUer's original description.^ Dr. Cobbold found 

 that his species, which differed from Miiller's, adhered by the larvah posterior extremity. 



In the following year Prof. P. J. Van Beneden described a Phoronis allied to 

 P. hi2ypocre2')ia under the name of Crejmia gracilis.* He gave a general account of its 

 structure — noting that the skin of both body and tentacles is covered with palpocils but 

 has no cilia ; that the perivisceral space has fluid but no corpuscles ; that the vascular 

 system has contractile vessels and nucleated red corpuscles. In each tentacle he recog- 

 nised only one blood-vessel ; and he observed the reproduction of the whole tentacular 

 crown. He overlooked the flexure of the alimentary canal, and thought it was simple 

 and straight, with a terminal anus. He considered Crepina [Phoronis) a tubicolar, 

 non-bristled Annelid, allied to the Cephalobranchiates. His specimens occurred in 

 oyster-shells, along with other boring forms. 



Dr. A. Krohn ^ next published an interesting account of the structure and further 

 development of Actinotrocha, in which he corrects certain interpretations of Gegen- 

 baur's, and shows that it is the larval form of a worm (probably a Sipunculid), with 

 tentacles like one of the Terebellacese, and with a body like Echiurus or Thalassema, 

 that is, without bristles, and that its blood is red and corpusculated. 



In 1859 Dr. F. D. Dyster of Tenby published notes on Phoronis hippocrepia, 

 with figures." His examples occurred in tubes (probably bored by themselves) in hard 

 limestone. He somewhat extended the description of the organs given by Dr. Strethill 

 Wright, and appears to have been one of the earliest to observe the discharge of the 

 ova, which issue from the oviducts into the space arched over by the inner tentacles — 

 where they form a compact and adherent white mass by aid of a glutinous secretion. 

 Moreover, he was enabled to watch the development of the ova, though it is probable 



1 Freah-water Polyzoa, p. 55. " Quart. Journ. Micr. Sc!., vol. vi. p. 50, pi. iv. figs. 10-12, 1858. 



» Viiie p. 22. * Ann. d. Sci. Nat., ser. 4, torn. x. pp. 11-23, pi. v. figs. 1-7, 1858. 



^ MuUer's Arcliiv f. Anat. u. PJiysioL, p. 293, 1858. '■ Trans. Linn. Svc. Lund., vol. xxii. p. 251, pi. xliv., 1859. 



