84 I. IJIMA : HEXACTINELLIDA. I. 



body- wall. Remarkable was tbe case of a specimen of medium 

 size in whicb the body, instead of being tubular, was more like 

 a compressed sac, — probably brought about in consequence of 

 tearing and other injuries sustained by the wall at several points. 

 The upper end of this specimen was closed by a sieve-plate 

 wliich bore the appearance of having been secondarily formed 

 after the loss of the original one. It would be superfluous to 

 enumerate all the other cases of malformations due to similar 

 causes. 



Once a specimen was obtained which was normal in all 

 respects except in bearing on one side near the upper end a 

 second shorter tube, connected with the first by means of a short, 

 solid, lateral bridge, through which the parenchymalia of the 

 one tube passed into the other. The smaller tube thus appended 

 looked very much like the upper torn end of a distinct indivi- 

 dual, having a regular sieve- plate above but being closed by 

 regenerated tissues at the opposite end. In fact I do not know 

 how to explain this abnormality unless it be that we really have 

 to do with such a portion of a separate individual which came 

 into fusion with its neighbor previous to its becoming cut off 

 from its basal region. 



Finally a few words about the commensal inmates. It is 

 interesting to note that the two species of Euplectella occurring 

 in the Sagami Sea, viz., E. imjwrlalis and E. 7/iarshaIli, have 

 each a special macrurous Crustacea as inmate in the gastral 

 cavity. For the first named species, this was a species which 

 unfortunately could not be satisfactorily identified, although 

 Dr. KisHiNOUYE for my sake kindly made efforts at its deter- 

 mination. It conies nearest to both Alpheidte and Ilyppolyt- 



