15 



respectively by the presence or absence of protective appendages to the 

 ocelli, or what are considered as such ; and as this distinctive character 

 also appears to imply important differences in other respects in the 

 structure of the animals, it is to be regarded as of the highest utility. 

 Prof. Forbes's monograph embraces those pulmograde Medusa which 

 have no protective appendages to the ocelli, and are from that 

 circumstance termed " naked-eyed," or the Gymnophthalmata. It is 

 to two species only of this family that the following observations 

 refer. These two species belong to two genera differing very widely 

 from each other, and of which one may be regarded as representing 

 the highest form of development in this class of Medusa, and the 

 other, perhaps, the lowest or most simple. The species which op- 

 portunity rather than choice has caused me to select for observation, 

 are Turris neglecta and a species of Thaumantias, which I am un- 

 able to name with certainty. Both species, with numerous others, 

 occurred abundantly in the sea around the northern and eastern 

 shores of the Isle of Wight, and also in Portsmouth Harbour ; and 

 the observations were made in the month of September last (1848). 



In Prof. E. Forbes's work the genus Turris is thus denned : — 

 " Umbrella subcylindrical or mitrate ; ovaries four, double, dense, 

 convoluted, lining the cavity of the peduncle ; vessels simple ; mar- 

 gin of the umbrella with numerous tentacula ; muscles of the disk 

 conspicuous and highly developed ; mouth of the peduncle fimbri- 

 ated." And the species T. neglecta as follows: — "The umbrella 

 transparent, smooth, and subhemispheric, inclining to conical ; sum- 

 mit slightly pointed ; subumbrella reaching to little more than half the 

 height of the former, slightly pyramidal with a truncated summit ; the 

 muscular bands are distinctly seen striping its sides ; peduncle large, 

 of a substantial aspect, in consequence of the compact masses of rich 

 crimson or vermilion convoluted and fimbriated ovaries which oc- 

 cupy its broader and upper half: the peduncle terminates in four 

 lips, fimbriated at their edges and highly muscular ; radiating vessels 

 four, simple ; marginal tentacles close set, more than sixty in num- 

 ber (16x 4 + 4), very contractile, being sometimes elongated into 

 hair-like filaments, and at others contracted into little knobs ; each 

 tentacle has a large bulbous base, the upper part of which bears a 

 brilliant ocellus, consisting of crimson pigment-cells, and there is 

 another speck, probably the site of an otolitic mass below." Coloured 

 figures also of the animal and of certain portions of its anatomy 

 magnified, are given in Plate III. of the same work. As my own 

 observations with respect to some of the anatomical and structural 



