1887. J PROF. F. J BELL ON HOLOTHUROIDS. 531 



its use may be it is impossible to state at present, but that it plays 

 some important part in the economy of the Marsupial can hardly 

 be doubted. 



The appearance of the patch of integument is not unlike that 

 figured by Garrod ' in Doreopsis luctuosa, but its position is very 

 different in the two forms. 



With this possible exception I am not able to compare the 

 glandular patch of Myrmecobius to any structure in any other 

 Marsupial ; the result of the present paper therefore must be the 

 addition of a new character to the diagnosis of Myrmecobius. 



3. Studies in the Holothuroidea. — VI. Descriptions of 

 new Species. By F. Jeffrey Bell, M.A.^ Sec. R.M.S., 

 Professor of Comparative Anatomy and Zoology in 

 King's College ^ 



[Eeceived June 21, 1887.] 



(Plate XLV.) 



During the somewhat protracted period in which I have been 

 engaged in determining the large collection of Holothurians in the 

 British Museum, I have noticed a few species of no interest suf- 

 ficient to justify immediate description, but which, being as yet 

 undescribed, may (on the completion of my work) have their 

 characteristics published. The date on which this paper is read 

 will explain why some of the species are named as they are. 



CucuMARiA sANCTi-joHANNis, sp. uov. (Plate XLV. fig. 1.) 



Body considerably elongated ; suckers highly retractile, confined 

 to ambulacra and arranged in irregular double rows ; no anal teeth. 



Calcareous oesophageal ring greatly reduced, the radial piece 

 small, slightly notched posteriorly, completely covered by the 

 insertion of the retractor muscle ; the interradial piece a fine fila- 

 ment. The retractors of extraordinary length, extending along two 

 thirds of the whole length of the body, with a broad belly of 

 insertion and long tendon-like band of origin. Stone-canal and 

 several Polian vesicles long. The genital tubes long, simple, and 

 numerous; the Cuvierian organs are apparently wanting. 



The spicules (Plate XLV. fig. 1) are numerous and exceedingly 

 simple ; at the narrow end there is a tendency to produce a spine ; 

 spicules of various stages are shown in the figure. 



Two specimens, measuring 50 and 95 millim. respectively, appear 

 each to have a greatest width of about 13 millim. 



Ojica, Goto Islands. Collected by Capt. St. John, R.N., H.M.S. 

 ' Sylvia.' 



This species is really remarkable ; not only for the reduction of the 

 oesophageal ring, which, it may be remembered, is quite aborted in 



' r. Z. S. 1875, p. IS, pi. viii. 2 p. Z. S. 1884, p. 563. 



