66 Prof. P. M. Duncan on the 



VIII. — Remarks on Dr. Hamanri's Researches in the Mor- 

 phology of the Echin&idea. Bj Prof. P. Martin Duncan, 

 F.R.S. &c. 



Dr. Hamann was good enough to send me a copj of his 

 very interesting and valuable " Vorlauiige Mittheilungen zur 

 Morphologic der Echiniden " * ; it arrived whilst I was en- 

 gaged in the studj of the histology of some of the same 

 structures which have been so well described by him, bu^: in 

 another group of genera. I venture to make the following 

 observations on two of the subjects which have especially 

 been considered by Dr. Hamann. 



I. The Glohiferen. 



These organs are a discovery of Dr. Hamann's, and, as 

 might have been expected from his former work on the Holo- 

 thuroidea, they are clearly described and are therefore readily 

 recognized. 



But the diagram given by Dr. Hamann of a globifer of 

 Sphcerechinus granidaris is rather misleading, and the real 

 organs would hardly be recognized therefrom. The three 

 " Driisenballen " are more united at their common base than 

 the diagram indicates, and the upper ends ai-e more or less con- 

 stricted and have very large foramina for the exit of the 

 mucus. The three masses are really continuous by their 

 outer coat at their bases and rest upon a shorter stem than 

 that shown in the figure. In ftict, owing to the diagram I 

 overlooked these organs in the first instance ; and so 

 did a fellow- worker. But when a number of tripartite 

 bodies fixed on short stalks, and which looked like stunted 

 ordinary pedicellari^e globiferte ( = gemmiformes) of Sphcere- 

 chinus j had been sepai-ated from the test and examined, their 

 identity with the organs described by Dr. Hamann and their 

 distinctness from the ordinary pedicellariie became evident. 



There is no glandular enlargement of the shaft in the 

 newly-described structures, and the stem, otherwise like tliat 

 of a pedicellaria, springs from the test and has the usual soft 

 structures at its origin. The head has three parts united at 

 the base, very tumid inferiorly and slightly roundedly angular 

 at the inner part, and much more rounded above than any 



* Sender- Abdruck aus den Sitzuugsbericbten der Jenaiscben Gesell- 

 scbaft fiir Medicin and Naturwissenscbaft, Jabrg. 1886; Ann. & Mag. 

 Nat. Hist. 1886, vol. xvii. pp. 388, 469. 



