Benham. — Further Notes on the Sipunculids of N.Z. 305 



to the tentacular arrangement of that arctic form. Again, in 

 the same text-book, a form named Stephanostoma by Danielssen 

 and Koren is stated to have " six great groups of tentacles " ; 

 but this form is regarded by Selenka as a Phascolosoma and not 

 a Sipunculus. 



The appearance, then, of this tentacular crown will be, when 

 fully everted, very different from that of either Dendrostoma or 

 Physcosoma. 



Internal Anatomy. — The longitudinal muscular coat consists 

 of about twenty-seven distinct bands in the middle of the 

 body : these run independently for considerable distances — i.e., 

 anastomoses are very infrequent ; necessarily they become more 

 frequent posteriorly, where the number of bands decreases. 



There are four retractors, all of the same length, arising from 

 the body- wall about 20 mm. below the base of the introvert. 

 The dorsal retractors arise from four longitudinal muscle-bands, 

 and the ventrals from three of them. 



The intestine, filled with sand, has such a thin wall — probably 

 due to post mortem changes— that it was impossible to trace the 

 coils, or to detect the extent of the spindle muscle, for the wall 

 burst on the slightest touch. The coils were attached to the 

 body-wall by numerous delicate threads. The rectum runs close 

 to the body-wall for a distance of 8 mm., and appears to be 

 adherent thereto. 



I was unable to detect any posterior cceca, nor were the 

 nephridia preserved. 



Remarks. — I have given a new name to this Sipunculus, as it 

 does not agree with the descriptions of any species in the small 

 collection of literature available. Unfortunately I have not 

 access to Selenka's monograph, so that it is possible that this 

 article is a work of supererogation. Judging by the reference to 

 the hook-like tubercles of S. australis, I expected that it would 

 belong to this species ; but the figure and description given by 

 Shipley* do not seem to bear out this idea : it is true neither 

 figure nor description is very detailed, but they are sufficient to 

 indicate general differences. His account says nothing of the 

 great axial cavity of the tubercle, and his figure shows gland 

 and tubercle as distinct things (pi. xviii., fig. 5) ; and the brief 

 diagnosis given by Quatrefagesf does not incline one to refer my 

 specimen to that species. The same negative result follows a 

 comparison of the diagnoses of other Australian species given by 

 the latter author. 



* Willey's Zool. Results : Report on Sipuncidoidea. 

 f Hist. Nat, des Armeies, ii., p. 619. 



20— Trans. 



