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



has thrown much doubt on this notion, yet I think it right to record it, for the sake of 

 the suggestion it may afford to those who may have the opportunity of folloAving up the 

 inquiry. Certain it is, that if all the accounts of it be correct records of actual phe- 

 nomena, and if they all refer (which, for the reasons I have already stated, I can scarcely 

 doubt) to the same specific type, the creature's life-history must vary considerably in 

 different circvmistances. 



Before referring to the published observations, I shall take advantage of the kindness 

 of Prof. Huxley, who has given me permission to append to my own account of Tomo- 

 pteris his descriptive notes and figures of two specimens captured by him in Torres Strait, 

 during the voyage of the ' Rattlesnake,' Aug. 1, 1849 : — 



" Body elongated, perfectly colourless and transparent, with thirty-one pairs of lateral 

 appendages, exclusive of what may be termed the head (fig. 8). The body is transversely 

 wrinkled, but not, properly speaking, annulated, there being a great many rings between 

 every two pairs of appendages, especially anteriorly. Posteriorly the wrinklings become 

 coarser and wider, but they are stUl numerous in proportion to the appendages, and are 

 not true annulations. 



" What may be considered to be the head, on account of its containing the mouth and 

 the organs of sense, is provided with two pairs of appendages. The first pair terminate 

 the anterior extremity of the body, the two appendages being united by their base, and 

 disposed transversely. They give the animal the appearance of a hammer-headed shark. 

 Their anterior edge is thin and delicate, the posterior rounded ; and this part contains a 

 cavity contiauous with that of the body. 



" Behind the first pan- of appendages the body suddenly narrows into a sort of neck, 

 which expands agaui into two other transverse processes stouter than the former. Each 

 of these is prolonged at its extremity into a long, slender, curved process nearly equal to 

 half the length of the body, and this process contains a still more slender cylindrical 

 spine, apparently of a horny nature. The end of the spine, covered by a membrane, pro- 

 jects into the cavity of the wide base of the appendage, and its extremity there gives 

 attachment to several bundles of muscular fibres, which go to be attached to the sides of 

 the cavity, and move the spine on occasion. 



" In the cavity of the body, situated just where the narrow neck expands iato the space 

 which lies between the second pair of appendages, is a transversely elongated mass, which 

 appears to be divided into two parts by a central hne. Towards the outer side of each of 

 these parts, there is, upon the dorsal surface, a rounded mass of black pigment, and, im- 

 bedded in the outer edge of this, a spherical (?), transparent, crystalline body ; these are 

 doubtless eye-spots, and the mass a double ganglion. Two delicate cords connect this 

 double ganglion with the parietes, and I think I could trace a bundle of fibres running 

 down on each side of the mouth ; but I am not certain about this, and I am quite sure 

 there was no chain of ganglia along the ventral surface of the body. 



" In the cavity of the body likewise, and extending between the second pair of append- 

 ages of the head and the first pair of the body, is a narrow, thick-coated, pyriform pha- 

 rynx. It commences in a rounded oval aperture on the ventral surface, and terminates 

 by opening into the wide stomach. This has much thinner walls, and continues as a 



