Rev. A. M. Norman on a new Echinoderm from Ireland. 113 



This genus is provisionally placed in the family Priapulacidse. 

 In the absence of tentacles around the mouth, and in their pre- 

 sence at the posterior extremity of the animal, Strephenterus 

 resembles Priapulus ; but in the latter genus the anal opening 

 is situated in the filamentous pyramidal tail. 



Strephenterus claviger, n. sp. 



Os infundibuliforme. Corpus in medio glabrum, ad extremitates 

 minutissime corrugatum, postice paucis tuberculis (microscopio 

 mode visendis) sparsum, tentaculisque (20-30) claviformibus in- 

 structum. — Long. 1^ unc., lat. \ unc. 



Habitat sinum Ban try in Hibernia. 



The mouth is funnel-formed. The body is smooth, except at 

 the extremities, which are finely corrugated. On the hinder 

 portion there are also a few microscopic tubercles scattered over 

 the surface, and that extremity is furnished with from twenty to 

 thirty club-shaped tentacular appendages. 



These tentacular appendages are of peculiar construction. 

 The longest and most fully expanded present the appearance of 

 fig. 2. The club is somewhat spathulate ; and about the centre 

 of the upper half is seen a small round aperture, apparently 

 opening into the interior ; below this there are two projecting 

 processes, one of which is larger than the other, and between 

 the bases of these two processes is seen the rudiment of a third. 

 Another state of the tentacles is shown in fig. 3, which is taken 

 from one of the shorter tentacles — shorter because less expanded, 

 or more probably less developed. Here there is no sign of the 

 central opening ; but the head seems to contain several pear- 

 shaped bodies, one of which has a blackish central spot. On 

 subjecting this tentacle to the compressorium, these pear-shaped 

 bodies escaped, and appeared to be composed entirely of granular 

 matter enclosed in thin sacs. 



What purpose in the life of the animal can these posterior 

 tentacles serve ? Professor Forbes called attention to the same 

 question with respect to the filamentous tail of Priapulus, the 

 function of which Sars has suggested to be respiratory ; it 

 seems probable that the tentacles of Strephenterus perform a 

 similar office. The opening in their heads would admit the 

 water through the pedicels into the wide space that exists be- 

 tween the inner and outer tunics of the animal (see fig. 4) j and 

 on examining the inner tunic with the microscope, it is seen to 

 be traversed by veins, while its outer surface (that of the upper 

 portion, at any rate) is clothed with fine cilia calculated to pro- 

 duce currents and cause the water to pass gently over its deli- 

 cate membrane. At the same time, the tentacles themselves 

 may j)ci-haps in some measure act as external branchiae. 



