BY H. LEIGHTON KESTEVEN. 283 



A, pyriformis flerdman. It is described as being "gregarious, 

 •several specimens growing together in one mass "; and it was 

 "found near low-water mark, among rocks" in Port Jackson. 

 Such is the common habit and habitat of the species here 

 associated with the name. That Stimpson collected in a locality 

 affected by this form, is proven for us by the fact that the Holo- 

 thurian, SyaaiDta dolabrifera^ which he described at the same 

 time, is very constantly found in similar situations. Fim^lly, the 

 other two species to which his description might applj^ are rare, 

 this one is extremely common, and Stimpson's stay in Sydney 

 was of very short duration. 



The differences between var. sydneiensis and the typical form 

 have already been noted by Herdman {loo. cit.). I incline to the 

 view that our form should rank as a distinct species, but my 

 European material does not permit me to make satisfactory com- 

 parisons; for that reason I append a description of the form, and 

 content myself with drawing attention to the name which is to 

 'be applied, if that view prove correct. 



External appearance. — The shape is elongate-ovate, somewhat 

 flattened from left to right, roundly truncate posteriorly, tapering 

 anteriorly to the siphons. The atrial siphon, when both 

 are fully extended, is somewhat shorter, and is placed a little 

 further back than the branchial. In preserved specimens both 

 siphons are usually retracted to such an extent that the anterior 

 end is abruptly truncate. In the body taken from the test 

 (PI. xxvii., figs. 13, 15, 16), the atrial siphon may appear the 

 longer, the branchial 'being much more strongly retracted. 

 Specimens from a sandy bottom are attached by the posterior 

 end only, usually several together; and in such cases the tests are 

 quite commonly completely fused. Specimens on the rocks may 

 be attached by the posterior end only, or along the length of the 

 dorsal side; the attachment is usually strengthened by the 

 development of root-like processes of the test. The size and pro- 

 portions are extremely variable. A large specimen will measure 

 as much as 10 centimetres in length, with a maximum diameter 

 of 33 centimetres. The largest specimens are those obtained 



