360 DR. W. B. CARPENTER ON TOMOPTERIS ONISCIFORMIS. 



among Heteropodous Mollusks. He would appear to have met with it only in its earlier 

 phase ; for his figure shows no more than twelve pairs of lateral appendages, without any 

 caudal prolongation. 



It seems, however, to have been previously (?) observed by Quoy and Gaimard, who 

 met with it in the Bay of Gibraltar during the voyage of the ' Astrolabe ;' but as their 

 account of it was first published in 1827 (Annales des Sciences Naturelles, tom. x. p. 235), 

 the name Briarea scolopendra, by which they designated it, must yield ia priority to that 

 of Eschscholtz. The specimen which they describe as having been taken ia the Bay of 

 Gibraltar, is stated to have attained a length of 4 inches. If there be no error in this 

 description, it must have been far larger than any that has been elsewhere met with. 

 They speak of it as possessing 24 or 25 pairs of lateral appendages or fin-feet ; of these, 

 however, their figure shows only 21 pairs, of which 17 belong to the body, and 4 to the 

 caudal prolongation. If this figure (which strikes me as in many respects rather an 

 ideal diagram than a true representation) approaches in any degree to the real propor- 

 tions of their specimen, its lateral appendages must have been vei-y much longer than 

 those figured by any of the other naturalists who have described it, their maximum 

 length being in the anterior portion of the body, and a progressive diminution taking 

 place as far as the commencement of the caudal prolongation, behind which they are 

 merely rudimentary. Thus the outside contour of the entire animal is not very dissimilar 

 to that of a boy's kite, the caudal prolongation representing the tail. It is somewhat 

 singular, that, notwithstanding the extreme transparency of this animal, MM. Quoy and 

 Gaimard were unable to make out its alimentary canal, although they described and 

 figvired what they believed to be ova. They considered Briarea to be a MoUusk, nearly 

 allied to Glaucus. 



In Muller's Archiv for 1847, there are a description and a figure of Tomopteris onisci- 

 formis by Busch, who met with it in the North Sea. This figure nearly corresponds, 

 except in the proportional shortness of the lateral appendages, with that of MM. Quoy 

 and Gaimard. The number of these appendages which Busch represents is 18 pairs, the 

 form of all lieing the same, and their size diminishing gradually from the 1st pair to 

 the 18th, which is close to the posterior extremity of the body, there being no distract 

 caudal prolongation. Busch described and figured the ova ia the perivisceral cavity, as 

 Professor Huxley has done subsequently ; and he also noticed other bodies which seem 

 to correspond with what Professor Huxley regarded as bundles of spermatozoa. 



In the succeeding volume of the same Journal (1848) is a very elaborate memoir by 

 Grube on Tomopteris, based on specimens collected by Krohn (probably in the Medi- 

 terranean), and preserved in the Musevim of St. Petersburg. This memoir is specially 

 devoted to the description of some of the minutest details of the structure of the animal, 

 and to the inquiry into its place in the zoological scale. Grube's figure of the entire animal 

 is not only small in scale, but is somewhat rudely sketched ; it represents twenty pairs of 

 lateral appendages, and a caudal prolongation of cylindrical form, apparently without 

 any appendages at aU. In his description, however, the author speaks of this caudal pro- 

 longation as bearing rudimentary fins, ia the form of whitish protuberances ; these, he 

 remarks, are as yet undivided ; whilst the fully-developed appendages of the anterior part 



