182 



the stone-canal has but a single curve, and in the smallest specimen 

 at hand the stone-canal is nearly quite straight. As the specimens 

 at hand show different degrees of curled stone-canals, correlated 

 with the size of the specimens, I suppose that it is the normal state 

 that the mature specimens in this species have the peculiar curled 

 stone-canal. The gonads are in the large specimens well developed 

 and branched. The intestine has a large loop and on the mesen- 

 teries there are ciliated funnels of the usual size and shape. 



The calcareous deposits in the posterior end of body are nearly 

 quite dissolved by acid in the preserving fluid. In the anterior end 

 of body where the dissolution has not been so great, there are an- 

 chors, anchor-plates and miliary granules. It is interesting to see 

 that the deposits in the posterior end of body seem to be more 

 dissoluble than those from the anterior end; one might be tempted 

 to suggest that this is not really the case, and that the mentioned 

 deposits are also nearly wanting when the specimen is alive. But 

 in the large collection of Synaptids at hand there are not few spec- 

 imens with the deposits partly dissolved, and in these specimens 

 the deposits from the posterior end are always the most attacked. 

 This is especially seen in the specimens at hand of reciprocans, 

 for in these specimens there were good deposits in both ends of 

 body three years ago, and now the deposits from the posterior end 

 have nearly totally disappeared; those from the anterior end are 

 only half dissolved. 



The anchors from the anterior end of the body (Fig. 24. 1) 

 measure ca. 280 /a in length and 200 /n in width. They are of the 

 usual shape with a finely dented stock and with minute knobs on 

 the vertex. The anchor-plates (Fig. 24. 2) measure ca. 200 fi in 

 length and 150 /n in width. The anterior margin of the articular 

 hole as well as the bridge are serrate. In the posterior end of the 

 plates there are three small holes. The miliary granules (Fig. 24. 4) 

 are circles of minute granules. This condition may perhaps be due 

 to a partly dissolution of normal rosettes. 



5. madreporica is the most closely related to psara and denti- 

 calata, but it differs in the exterior as well as in the shape of the 

 calcareous deposits so much from these two species that it would 

 be unjustifiable to refer it to them. 



