made during the Voyage of H. M.S. ' Challenger.' 573 



six to seven folds, and is covered with papillae, which towards the mouth 

 change into chitinous protuberances. In each of these one finds some 

 unicellular glands, granulated -cells showing a nucleus and a nucleolus. 

 Unfortunately the posterior portion of its body had been destroyed before 

 we got it. 



The commonest G-ephyrean genus is undoubtedly Sipunculus, in shallow 

 water as well as in deep water ; we got it here three times, in depths 

 from 350 to 2500 fathoms. 



"We have been particularly looking out for Phoronis, but have never 

 been able to find it, and feel now nearly sure that it does not inhabit, as 

 a rule, the great depths. Stemaspis, however, has been got in 1700 

 fathoms of water, and besides this annelid another form (600 fathoms off 

 Gromera), which has an intestine coiled up like that of a Grephyrean, and 

 only three pairs of setigerous feet in the posterior portion of its body. 

 It is in many ways peculiar ; but I am unable as yet to determine its 

 systematical position from want of books of reference. 



Among the tube-building annelids the Clymenidse, TerebellidaB, and 

 Serpulidae are characteristic inhabitants of great depths, and go, like that 

 Myriochele, sp., which I have figured (' Nature,' 1873), to a depth of 

 2900 fathoms. We missed Clicetopterus, Siphonostomum, and Pectinaria, 

 which for various reasons we had expected to find in rather deep water. 

 Of free-living annelids, however, there is a large amount, AphroditidEe, 

 Palmyridae, Eunicinse (Onuphis is very common), and Glycerida3 being 

 the families chiefly represented. I found that sometimes genera which 

 have got eyes in shallow water are represented by a blind species in deep 

 water — an observation which, I think, has also been made by Professor 

 Ehlers. 



Having described shortly before I joined this expedition a northern 

 form of Balanoglossus (B. Kujoferi, from the Oeresund near Copenhagen, 

 14 fathoms), I was of course greatly interested in a large fragment of 

 this peculiar worm which came up near the west coast of Africa from 

 2500 fathoms. Unlike its northern cousins, this species has very bright 

 colours, its head being yellow, its collar bright red, and its body yellowish 

 red. The head alone has a width of 18 and a height of 11 millims. In 

 deep water this genus was seldom again obtained ; and I may therefore 

 now mention that in most tropical places in the Pacific I found this 

 genus to be an inhabitant of the shallow water, as I constantly found the 

 larva known under the name of Tomaria, and sometimes such stages of 

 its development which have been shown by Mecznikon 2 and A. Agassiz to 

 belong to Balanoglossus. 



Parasitical Cirripedia are by no means rare on the shallow-water 

 shrimps, and are found as well among those coming from great depths. 

 We have noticed a Peltogaster here and there, but feel sure that a careful 

 examination of the Macrurous Decapods will show many more cases. 



Both groups of the Cirripedia Thoracica are well known in a fossil state ; 



