244 



SCIENCE. 



[N. S. Vol. III. No. 59. 



intimately associated with the failing health of 

 Prof. Huxley, whd after making a splendid 

 series of anatomical drawings, illustrating 

 nearly every detail of the gross anatomy, felt 

 himself unable to supply the text. He there- 

 fore placed his notes and drawings at the dis- 

 position of Dr. Pelseneer who has furnished a 

 description of them, together with some addi- 

 tional details drawn from his examination of 

 two other specimens submitted to him by Prof. 

 Giard. 



It is probable that there were reasons why 

 the work was not made more complete which do 

 not appear in the preface, and in this way the 

 absence of histological details may be accounted 

 for. As regards the gross anatomy there is, 

 doubtless, little left for future anatomists now 

 that Huxley has cleared the path, and the pres- 

 ent monograph will remain for the future the 

 standard of reference for this genus. This be- 

 ing the case, the rarity of the animal being 

 considered, it is perhaps worth while to point 

 out wherein Dr. Pelseneer has come to too 

 hasty and even erroneous conclusions from the 

 data he possessed. The U. S. National Museum 

 possesses a nearly perfect specimen of Spirula 

 taken from the mouth of a deep-sea fish trawled 

 in the Gulf of Mexico, and also a fragment 

 found at Palm Beach, Florida. The possession 

 of the former enables me to correct certain de- 

 tails of the monograph. 



Spirula is a remarkable animal for a cuttle- 

 fish. It is short and stout, with the posterior 

 (caudal) end blunt, truncate and furnished with 

 what looks like a sucking disk nearly as large 

 as the diameter of the animal's body. In the 

 cavity of this organ is seen a central prominence 

 of cartilaginous consistency, the homologue of 

 the terminal cone of Belemnites or Onychoteuthis 

 robusta. On each side the ' fins ' or lateral ex- 

 pansions of the mantle occupy a dorso-ventral 

 plane and lateral and terminal position instead 

 of being, as in the quickly swimming forms, in 

 the dorsal plane or parallel to it. In short, they 

 look as if they were adapted to serve as but- 

 tresses if the animal should fasten itself to some 

 hard object by its terminal disk, with its body 

 in a vertical attitude, like a sea anemone. 



Spirula is extremely rare in collections, though 

 its siphunculated shell is abundant on the 



beaches or floating on the sea in certain regions. 

 Nearly all the specimens which have been taken 

 with soft parts more or less preserved are of two 

 sorts; one has the cylindrical muscular cortical 

 portion complete and uninjured, but the head 

 and viscera are missing, leaving the rest buoyed 

 up by the shell. The other sort has the viscera 

 and terminal portions in a perfect state, but the 

 outer layers of the cortex lacerated or removed. 

 The National Museum specimen is of the latter 

 kind; the epithelium, chromatophoric layer and 

 part of the strong muscular layer below it, are 

 scraped off" and partly hang in strings scratched 

 longitudinally from the tail end forward to the 

 margin of the cylinder. The delicate outer 

 layer over the posterior end is perfectly intact, 

 as are the fins. There can be no reasonable 

 doubt that this scraping is due to the teeth of 

 the fish in whose mouth it was found. Both 

 the Challenger and the Blake specimens were 

 in this condition, and Prof. Giard' s were also 

 incomplete, though to what extent Pelseneer 

 does not state. The aboral disk is strongly at- 

 tached to the shell, and when the specimen is 

 iresh and elastic, if the end of the finger is 

 pressed upon the disk and withdrawn, a distinct 

 sensation of suction is felt, though the harden- 

 ing effect of the alcohol puts an end to this after 

 a time. 



Now, the only hjrpothesis which seems to 

 reconcile all the facts in the case is that the 

 aboral disk may serve as a means of attachment 

 to hard bodies, so that the Spirula, while not 

 unable to swim, is in general sedentary. This 

 explains why living specimens are not taken 

 free in the ocean. When alive, on this hypo- 

 thesis, it usually adheres to hard bodies. If it 

 relaxes its hold, through disease or weakness, 

 it slowly rises by the gas contained in the 

 chambers of the shell, and the viscera under 

 this condition decay first. If forcibly pulled off 

 from its perch by a fish, the epithelium is 

 likely to be lacerated, something difficult to 

 explain if the animal were taken free swim- 

 ming, as the swimming cephalopods taken 

 from fish stomachs are not lacerated in this 

 manner when small enough to be swallowed 

 whole. It is undoubtedly a deep-water animal. 



The testimony of Rumphius is rightly re- 

 jected by Pelseneer, but we cannot agree with 



