258 Mr. J. E. Gray on the Animal of Spirula. 



I need scarcely make any other remark on the great interest 

 of this animal, than to observe that there is every reason to believe 

 that it is the nearest recent ally of the Ammonites so abundant 

 and so numerous in kinds found in the different fossiliferous 

 strata. 



The animal of this genus has only hitherto been known from 

 a figure in the Atlas of Peron and Lesueur, ' Voyages/ t. 30. f. 4, 

 copied in Blainv. ^Man. Mol.^ t. 4. f. 1, and in Rang. 'Man. 

 Moll.^ t. 1. f. 4. A very slight sketch of it is engraved in the 

 'Encyclopedic Methodique/ t. 465. f. 5, from a drawing made by 

 Lamarck with chalk to illustrate his lectures, and from a shell 

 with part of the skin of the mantle attached to it, which was 

 found by Cranch and brought home from the Congo expedition. 



Lamarck^s figure above-mentioned gives a better general 

 idea of the animal than was expected. Peron and Lesueur's 

 figure on the other hand erroneously represents the animal as 

 having ten arms of unequal length like the Sea-spiders {Octopus); 

 probably in his specimens the long arms had been broken off, as 

 in the one brought home by Mr. Earl, and the peduncles of these 

 arms were mistaken for short arms. CrancVs specimen was so 

 imperfect that it only showed that the skin was like that of other 

 cuttle-fish, and it appears to have an opening at the hinder extre- 

 mity of the body not found in cuttle-fish which could not be un- 

 derstood, but which is explained by Mr. Cuming^s specimen. 



The long arms unfortunately have lost their terminal club. 



The shorter arms are triangular, gradually tapering, flattish, 

 rounded, and without any fin-like edge behind or on the hinder 

 edges. Their inner surface is covered with numerous equidistant, 

 very small, slightly pedicelled, circular acetabula or suckers, 

 strengthened with an entire or very minutely denticulated horny 

 ring, placed in about six longitudinal series, and diminishing in 

 size as the arms become attenuated. They are equidistant, ex- 

 cept the two lower or ventral pair, which are separated by a broad 

 shallow groove on the lower side of the head ; the lower pair on 

 each side are united together by a short membrane on the inner 

 and outer side, which together form a short sheath round the base 

 of the pedicel of the longer arm. 



The animal has all the general external characters of the cuttle- 

 fish ; that is to say, it has a large distinct head with eyes on each 

 side, eight short conical arms with series of small discs on the 

 inner side, two long arms with elongated peduncles, and a bag- 

 like mantle with a process in the middle above, and one on each 

 side of the anal tube below ; but it differs from the cuttle-fish in 

 being entirely destitute of any fins, being rather compressed be- 

 hind, and showing in the specimen under examination a part of 

 the whorls of the shell above and below; but from the ragged edges 



